feat: telemetry progress

rust/Cargo.lock

@@ -25,6 +25,7 @@ dependencies = [
  "runtime",
  "serde",
  "serde_json",
+ "telemetry",
  "tokio",
 ]
 
@@ -1096,6 +1097,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sha2",
+ "telemetry",
  "tokio",
  "walkdir",
 ]
@@ -1428,6 +1430,14 @@ dependencies = [
  "yaml-rust",
 ]
 
+[[package]]
+name = "telemetry"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.18"

rust/crates/api/Cargo.toml

@@ -10,6 +10,7 @@ reqwest = { version = "0.12", default-features = false, features = ["json", "rus
 runtime = { path = "../runtime" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+telemetry = { path = "../telemetry" }
 tokio = { version = "1", features = ["io-util", "macros", "net", "rt-multi-thread", "time"] }
 
 [lints]

rust/crates/api/src/client.rs

@@ -1,20 +1,20 @@
 use std::collections::VecDeque;
-use std::sync::{Arc, Mutex};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 use runtime::{
-    load_oauth_credentials, save_oauth_credentials, OAuthConfig, OAuthRefreshRequest,
+    format_usd, load_oauth_credentials, pricing_for_model, save_oauth_credentials, OAuthConfig,
-    OAuthTokenExchangeRequest,
+    OAuthRefreshRequest, OAuthTokenExchangeRequest,
 };
 use serde::Deserialize;
+use serde_json::{Map, Value};
+use telemetry::{AnalyticsEvent, AnthropicRequestProfile, ClientIdentity, SessionTracer};
 
 use crate::error::ApiError;
-use crate::prompt_cache::{PromptCache, PromptCacheRecord, PromptCacheStats};
 use crate::sse::SseParser;
-use crate::types::{MessageRequest, MessageResponse, StreamEvent, Usage};
+use crate::types::{MessageRequest, MessageResponse, StreamEvent};
 
 const DEFAULT_BASE_URL: &str = "https://api.anthropic.com";
-const ANTHROPIC_VERSION: &str = "2023-06-01";
+const MESSAGES_PATH: &str = "/v1/messages";
 const REQUEST_ID_HEADER: &str = "request-id";
 const ALT_REQUEST_ID_HEADER: &str = "x-request-id";
 const DEFAULT_INITIAL_BACKOFF: Duration = Duration::from_millis(200);
@@ -110,8 +110,8 @@ pub struct AnthropicClient {
     max_retries: u32,
     initial_backoff: Duration,
     max_backoff: Duration,
-    prompt_cache: Option<PromptCache>,
+    request_profile: AnthropicRequestProfile,
-    last_prompt_cache_record: Arc<Mutex<Option<PromptCacheRecord>>>,
+    session_tracer: Option<SessionTracer>,
 }
 
 impl AnthropicClient {
@@ -124,8 +124,8 @@ impl AnthropicClient {
             max_retries: DEFAULT_MAX_RETRIES,
             initial_backoff: DEFAULT_INITIAL_BACKOFF,
             max_backoff: DEFAULT_MAX_BACKOFF,
-            prompt_cache: None,
+            request_profile: AnthropicRequestProfile::default(),
-            last_prompt_cache_record: Arc::new(Mutex::new(None)),
+            session_tracer: None,
         }
     }
 
@@ -138,8 +138,8 @@ impl AnthropicClient {
             max_retries: DEFAULT_MAX_RETRIES,
             initial_backoff: DEFAULT_INITIAL_BACKOFF,
             max_backoff: DEFAULT_MAX_BACKOFF,
-            prompt_cache: None,
+            request_profile: AnthropicRequestProfile::default(),
-            last_prompt_cache_record: Arc::new(Mutex::new(None)),
+            session_tracer: None,
         }
     }
 
@@ -184,6 +184,39 @@ impl AnthropicClient {
         self
     }
 
+    #[must_use]
+    pub fn with_request_profile(mut self, request_profile: AnthropicRequestProfile) -> Self {
+        self.request_profile = request_profile;
+        self
+    }
+
+    #[must_use]
+    pub fn with_client_identity(mut self, client_identity: ClientIdentity) -> Self {
+        self.request_profile.client_identity = client_identity;
+        self
+    }
+
+    #[must_use]
+    pub fn with_beta(mut self, beta: impl Into<String>) -> Self {
+        let beta = beta.into();
+        if !self.request_profile.betas.contains(&beta) {
+            self.request_profile.betas.push(beta);
+        }
+        self
+    }
+
+    #[must_use]
+    pub fn with_extra_body_param(mut self, key: impl Into<String>, value: Value) -> Self {
+        self.request_profile.extra_body.insert(key.into(), value);
+        self
+    }
+
+    #[must_use]
+    pub fn with_session_tracer(mut self, session_tracer: SessionTracer) -> Self {
+        self.session_tracer = Some(session_tracer);
+        self
+    }
+
     #[must_use]
     pub fn with_retry_policy(
         mut self,
@@ -197,30 +230,6 @@ impl AnthropicClient {
         self
     }
 
-    #[must_use]
-    pub fn with_prompt_cache(mut self, prompt_cache: PromptCache) -> Self {
-        self.prompt_cache = Some(prompt_cache);
-        self
-    }
-
-    #[must_use]
-    pub fn prompt_cache(&self) -> Option<&PromptCache> {
-        self.prompt_cache.as_ref()
-    }
-
-    #[must_use]
-    pub fn prompt_cache_stats(&self) -> Option<PromptCacheStats> {
-        self.prompt_cache.as_ref().map(PromptCache::stats)
-    }
-
-    #[must_use]
-    pub fn take_last_prompt_cache_record(&self) -> Option<PromptCacheRecord> {
-        self.last_prompt_cache_record()
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner)
-            .take()
-    }
-
     #[must_use]
     pub fn auth_source(&self) -> &AuthSource {
         &self.auth
@@ -230,19 +239,10 @@ impl AnthropicClient {
         &self,
         request: &MessageRequest,
     ) -> Result<MessageResponse, ApiError> {
-        self.store_last_prompt_cache_record(None);
         let request = MessageRequest {
             stream: false,
             ..request.clone()
         };
-        if let Some(prompt_cache) = &self.prompt_cache {
-            if let Some(response) = prompt_cache.lookup_completion(&request) {
-                self.store_last_prompt_cache_record(Some(prompt_cache_record_from_stats(
-                    prompt_cache.stats(),
-                )));
-                return Ok(response);
-            }
-        }
         let response = self.send_with_retry(&request).await?;
         let request_id = request_id_from_headers(response.headers());
         let mut response = response
@@ -252,10 +252,7 @@ impl AnthropicClient {
         if response.request_id.is_none() {
             response.request_id = request_id;
         }
-        if let Some(prompt_cache) = &self.prompt_cache {
+        self.record_response_usage(&response);
-            let record = prompt_cache.record_response(&request, &response);
-            self.store_last_prompt_cache_record(Some(record));
-        }
         Ok(response)
     }
 
@@ -263,7 +260,6 @@ impl AnthropicClient {
         &self,
         request: &MessageRequest,
     ) -> Result<MessageStream, ApiError> {
-        self.store_last_prompt_cache_record(None);
         let response = self
             .send_with_retry(&request.clone().with_streaming())
             .await?;
@@ -273,30 +269,9 @@ impl AnthropicClient {
             parser: SseParser::new(),
             pending: VecDeque::new(),
             done: false,
-            cache_tracking: self
-                .prompt_cache
-                .as_ref()
-                .map(|prompt_cache| StreamCacheTracking {
-                    prompt_cache: prompt_cache.clone(),
-                    request: request.clone().with_streaming(),
-                    last_usage: None,
-                    finalized: false,
-                    last_record: self.last_prompt_cache_record.clone(),
-                }),
         })
     }
 
-    fn store_last_prompt_cache_record(&self, record: Option<PromptCacheRecord>) {
-        *self
-            .last_prompt_cache_record()
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner) = record;
-    }
-
-    fn last_prompt_cache_record(&self) -> &Arc<Mutex<Option<PromptCacheRecord>>> {
-        &self.last_prompt_cache_record
-    }
-
     pub async fn exchange_oauth_code(
         &self,
         config: &OAuthConfig,
@@ -346,18 +321,30 @@ impl AnthropicClient {
 
         loop {
             attempts += 1;
+            self.record_request_started(request, attempts);
             match self.send_raw_request(request).await {
                 Ok(response) => match expect_success(response).await {
-                    Ok(response) => return Ok(response),
+                    Ok(response) => {
+                        self.record_request_succeeded(request, attempts, &response);
+                        return Ok(response);
+                    }
                     Err(error) if error.is_retryable() && attempts <= self.max_retries + 1 => {
+                        self.record_request_failed(request, attempts, &error);
                         last_error = Some(error);
                     }
-                    Err(error) => return Err(error),
+                    Err(error) => {
+                        self.record_request_failed(request, attempts, &error);
+                        return Err(error);
+                    }
                 },
                 Err(error) if error.is_retryable() && attempts <= self.max_retries + 1 => {
+                    self.record_request_failed(request, attempts, &error);
                     last_error = Some(error);
                 }
-                Err(error) => return Err(error),
+                Err(error) => {
+                    self.record_request_failed(request, attempts, &error);
+                    return Err(error);
+                }
             }
 
             if attempts > self.max_retries {
@@ -377,18 +364,213 @@ impl AnthropicClient {
         &self,
         request: &MessageRequest,
     ) -> Result<reqwest::Response, ApiError> {
-        let request_url = format!("{}/v1/messages", self.base_url.trim_end_matches('/'));
+        let request_url = format!("{}{}", self.base_url.trim_end_matches('/'), MESSAGES_PATH);
-        let request_builder = self
+        let mut request_builder = self
             .http
             .post(&request_url)
-            .header("anthropic-version", ANTHROPIC_VERSION)
             .header("content-type", "application/json");
+        for (name, value) in self.request_profile.header_pairs() {
+            request_builder = request_builder.header(name, value);
+        }
         let mut request_builder = self.auth.apply(request_builder);
 
-        request_builder = request_builder.json(request);
+        let request_body = self.request_profile.render_json_body(request)?;
+        request_builder = request_builder.json(&request_body);
         request_builder.send().await.map_err(ApiError::from)
     }
 
+    fn record_request_started(&self, request: &MessageRequest, attempt: u32) {
+        if let Some(tracer) = &self.session_tracer {
+            tracer.record_http_request_started(
+                attempt,
+                "POST",
+                MESSAGES_PATH,
+                self.request_attributes(request),
+            );
+        }
+    }
+
+    fn record_request_succeeded(
+        &self,
+        request: &MessageRequest,
+        attempt: u32,
+        response: &reqwest::Response,
+    ) {
+        if let Some(tracer) = &self.session_tracer {
+            tracer.record_http_request_succeeded(
+                attempt,
+                "POST",
+                MESSAGES_PATH,
+                response.status().as_u16(),
+                request_id_from_headers(response.headers()),
+                self.request_attributes(request),
+            );
+        }
+    }
+
+    fn record_request_failed(&self, request: &MessageRequest, attempt: u32, error: &ApiError) {
+        if let Some(tracer) = &self.session_tracer {
+            tracer.record_http_request_failed(
+                attempt,
+                "POST",
+                MESSAGES_PATH,
+                error.to_string(),
+                error.is_retryable(),
+                self.error_attributes(request, error),
+            );
+        }
+    }
+
+    fn record_response_usage(&self, response: &MessageResponse) {
+        let Some(tracer) = &self.session_tracer else {
+            return;
+        };
+
+        let cost = response.usage.estimated_cost_usd(&response.model);
+        let pricing_source = if pricing_for_model(&response.model).is_some() {
+            "model-specific"
+        } else {
+            "default-sonnet"
+        };
+
+        let mut properties = Map::new();
+        properties.insert("model".to_string(), Value::String(response.model.clone()));
+        properties.insert(
+            "pricing_source".to_string(),
+            Value::String(pricing_source.to_string()),
+        );
+        properties.insert(
+            "input_tokens".to_string(),
+            Value::from(response.usage.input_tokens),
+        );
+        properties.insert(
+            "output_tokens".to_string(),
+            Value::from(response.usage.output_tokens),
+        );
+        properties.insert(
+            "cache_creation_input_tokens".to_string(),
+            Value::from(response.usage.cache_creation_input_tokens),
+        );
+        properties.insert(
+            "cache_read_input_tokens".to_string(),
+            Value::from(response.usage.cache_read_input_tokens),
+        );
+        properties.insert(
+            "total_tokens".to_string(),
+            Value::from(response.usage.total_tokens()),
+        );
+        properties.insert(
+            "estimated_cost_usd".to_string(),
+            Value::String(format_usd(cost.total_cost_usd())),
+        );
+        properties.insert(
+            "estimated_input_cost_usd".to_string(),
+            Value::String(format_usd(cost.input_cost_usd)),
+        );
+        properties.insert(
+            "estimated_output_cost_usd".to_string(),
+            Value::String(format_usd(cost.output_cost_usd)),
+        );
+        properties.insert(
+            "estimated_cache_creation_cost_usd".to_string(),
+            Value::String(format_usd(cost.cache_creation_cost_usd)),
+        );
+        properties.insert(
+            "estimated_cache_read_cost_usd".to_string(),
+            Value::String(format_usd(cost.cache_read_cost_usd)),
+        );
+        if let Some(request_id) = &response.request_id {
+            properties.insert("request_id".to_string(), Value::String(request_id.clone()));
+        }
+
+        tracer.record_analytics(AnalyticsEvent {
+            namespace: "api".to_string(),
+            action: "message_usage".to_string(),
+            properties,
+        });
+    }
+
+    fn request_attributes(&self, request: &MessageRequest) -> Map<String, Value> {
+        let mut attributes = Map::new();
+        attributes.insert("model".to_string(), Value::String(request.model.clone()));
+        attributes.insert("stream".to_string(), Value::Bool(request.stream));
+        attributes.insert("max_tokens".to_string(), Value::from(request.max_tokens));
+        attributes.insert(
+            "message_count".to_string(),
+            Value::from(u64::try_from(request.messages.len()).unwrap_or(u64::MAX)),
+        );
+        attributes.insert(
+            "tool_count".to_string(),
+            Value::from(
+                u64::try_from(request.tools.as_ref().map_or(0, Vec::len)).unwrap_or(u64::MAX),
+            ),
+        );
+        attributes.insert(
+            "beta_count".to_string(),
+            Value::from(u64::try_from(self.request_profile.betas.len()).unwrap_or(u64::MAX)),
+        );
+        if !self.request_profile.betas.is_empty() {
+            attributes.insert(
+                "betas".to_string(),
+                Value::Array(
+                    self.request_profile
+                        .betas
+                        .iter()
+                        .cloned()
+                        .map(Value::String)
+                        .collect(),
+                ),
+            );
+        }
+        if !self.request_profile.extra_body.is_empty() {
+            attributes.insert(
+                "extra_body_keys".to_string(),
+                Value::Array(
+                    self.request_profile
+                        .extra_body
+                        .keys()
+                        .cloned()
+                        .map(Value::String)
+                        .collect(),
+                ),
+            );
+        }
+        attributes
+    }
+
+    fn error_attributes(&self, request: &MessageRequest, error: &ApiError) -> Map<String, Value> {
+        let mut attributes = self.request_attributes(request);
+        match error {
+            ApiError::Api {
+                status,
+                error_type,
+                message,
+                ..
+            } => {
+                attributes.insert("status".to_string(), Value::from(status.as_u16()));
+                if let Some(error_type) = error_type {
+                    attributes.insert("error_type".to_string(), Value::String(error_type.clone()));
+                }
+                if let Some(message) = message {
+                    attributes.insert("api_message".to_string(), Value::String(message.clone()));
+                }
+            }
+            ApiError::Http(_) => {
+                attributes.insert("error_type".to_string(), Value::String("http".to_string()));
+            }
+            ApiError::Json(_) => {
+                attributes.insert("error_type".to_string(), Value::String("json".to_string()));
+            }
+            _ => {
+                attributes.insert(
+                    "error_type".to_string(),
+                    Value::String("client".to_string()),
+                );
+            }
+        }
+        attributes
+    }
+
     fn backoff_for_attempt(&self, attempt: u32) -> Result<Duration, ApiError> {
         let Some(multiplier) = 1_u32.checked_shl(attempt.saturating_sub(1)) else {
             return Err(ApiError::BackoffOverflow {
@@ -594,7 +776,6 @@ pub struct MessageStream {
     parser: SseParser,
     pending: VecDeque<StreamEvent>,
     done: bool,
-    cache_tracking: Option<StreamCacheTracking>,
 }
 
 impl MessageStream {
@@ -606,9 +787,6 @@ impl MessageStream {
     pub async fn next_event(&mut self) -> Result<Option<StreamEvent>, ApiError> {
         loop {
             if let Some(event) = self.pending.pop_front() {
-                if let Some(cache_tracking) = &mut self.cache_tracking {
-                    cache_tracking.observe(&event);
-                }
                 return Ok(Some(event));
             }
 
@@ -616,14 +794,8 @@ impl MessageStream {
                 let remaining = self.parser.finish()?;
                 self.pending.extend(remaining);
                 if let Some(event) = self.pending.pop_front() {
-                    if let Some(cache_tracking) = &mut self.cache_tracking {
-                        cache_tracking.observe(&event);
-                    }
                     return Ok(Some(event));
                 }
-                if let Some(cache_tracking) = &mut self.cache_tracking {
-                    cache_tracking.finalize();
-                }
                 return Ok(None);
             }
 
@@ -639,53 +811,6 @@ impl MessageStream {
     }
 }
 
-#[derive(Debug, Clone)]
-struct StreamCacheTracking {
-    prompt_cache: PromptCache,
-    request: MessageRequest,
-    last_usage: Option<Usage>,
-    finalized: bool,
-    last_record: Arc<Mutex<Option<PromptCacheRecord>>>,
-}
-
-impl StreamCacheTracking {
-    fn observe(&mut self, event: &StreamEvent) {
-        match event {
-            StreamEvent::MessageStart(event) => {
-                self.last_usage = Some(event.message.usage.clone());
-            }
-            StreamEvent::MessageDelta(event) => {
-                self.last_usage = Some(event.usage.clone());
-            }
-            StreamEvent::ContentBlockStart(_)
-            | StreamEvent::ContentBlockDelta(_)
-            | StreamEvent::ContentBlockStop(_)
-            | StreamEvent::MessageStop(_) => {}
-        }
-    }
-
-    fn finalize(&mut self) {
-        if self.finalized {
-            return;
-        }
-        if let Some(usage) = &self.last_usage {
-            let record = self.prompt_cache.record_usage(&self.request, usage);
-            *self
-                .last_record
-                .lock()
-                .unwrap_or_else(std::sync::PoisonError::into_inner) = Some(record);
-        }
-        self.finalized = true;
-    }
-}
-
-fn prompt_cache_record_from_stats(stats: PromptCacheStats) -> PromptCacheRecord {
-    PromptCacheRecord {
-        cache_break: None,
-        stats,
-    }
-}
-
 async fn expect_success(response: reqwest::Response) -> Result<reqwest::Response, ApiError> {
     let status = response.status();
     if status.is_success() {
@@ -730,7 +855,7 @@ mod tests {
     use super::{ALT_REQUEST_ID_HEADER, REQUEST_ID_HEADER};
     use std::io::{Read, Write};
     use std::net::TcpListener;
-    use std::sync::atomic::{AtomicU64, Ordering};
+    use std::sync::{Mutex, OnceLock};
     use std::thread;
     use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
@@ -740,15 +865,19 @@ mod tests {
         now_unix_timestamp, oauth_token_is_expired, resolve_saved_oauth_token,
         resolve_startup_auth_source, AnthropicClient, AuthSource, OAuthTokenSet,
     };
-    use crate::test_env_lock;
     use crate::types::{ContentBlockDelta, MessageRequest};
 
+    fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+        LOCK.get_or_init(|| Mutex::new(()))
+            .lock()
+            .expect("env lock")
+    }
+
     fn temp_config_home() -> std::path::PathBuf {
-        static NEXT_ID: AtomicU64 = AtomicU64::new(0);
         std::env::temp_dir().join(format!(
-            "api-oauth-test-{}-{}-{}",
+            "api-oauth-test-{}-{}",
             std::process::id(),
-            NEXT_ID.fetch_add(1, Ordering::Relaxed),
             SystemTime::now()
                 .duration_since(UNIX_EPOCH)
                 .expect("time")
@@ -788,7 +917,7 @@ mod tests {
 
     #[test]
     fn read_api_key_requires_presence() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
         std::env::remove_var("ANTHROPIC_API_KEY");
         std::env::remove_var("CLAUDE_CONFIG_HOME");
@@ -798,7 +927,7 @@ mod tests {
 
     #[test]
     fn read_api_key_requires_non_empty_value() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         std::env::set_var("ANTHROPIC_AUTH_TOKEN", "");
         std::env::remove_var("ANTHROPIC_API_KEY");
         let error = super::read_api_key().expect_err("empty key should error");
@@ -808,7 +937,7 @@ mod tests {
 
     #[test]
     fn read_api_key_prefers_api_key_env() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         std::env::set_var("ANTHROPIC_AUTH_TOKEN", "auth-token");
         std::env::set_var("ANTHROPIC_API_KEY", "legacy-key");
         assert_eq!(
@@ -821,7 +950,7 @@ mod tests {
 
     #[test]
     fn read_auth_token_reads_auth_token_env() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         std::env::set_var("ANTHROPIC_AUTH_TOKEN", "auth-token");
         assert_eq!(super::read_auth_token().as_deref(), Some("auth-token"));
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
@@ -841,7 +970,7 @@ mod tests {
 
     #[test]
     fn auth_source_from_env_combines_api_key_and_bearer_token() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         std::env::set_var("ANTHROPIC_AUTH_TOKEN", "auth-token");
         std::env::set_var("ANTHROPIC_API_KEY", "legacy-key");
         let auth = AuthSource::from_env().expect("env auth");
@@ -853,7 +982,7 @@ mod tests {
 
     #[test]
     fn auth_source_from_saved_oauth_when_env_absent() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         let config_home = temp_config_home();
         std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
@@ -892,7 +1021,7 @@ mod tests {
 
     #[test]
     fn resolve_saved_oauth_token_refreshes_expired_credentials() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         let config_home = temp_config_home();
         std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
@@ -924,7 +1053,7 @@ mod tests {
 
     #[test]
     fn resolve_startup_auth_source_uses_saved_oauth_without_loading_config() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         let config_home = temp_config_home();
         std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
@@ -948,7 +1077,7 @@ mod tests {
 
     #[test]
     fn resolve_startup_auth_source_errors_when_refreshable_token_lacks_config() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         let config_home = temp_config_home();
         std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
@@ -980,7 +1109,7 @@ mod tests {
 
     #[test]
     fn resolve_saved_oauth_token_preserves_refresh_token_when_refresh_response_omits_it() {
-        let _guard = test_env_lock();
+        let _guard = env_lock();
         let config_home = temp_config_home();
         std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
         std::env::remove_var("ANTHROPIC_AUTH_TOKEN");

rust/crates/api/src/lib.rs

@@ -1,6 +1,5 @@
 mod client;
 mod error;
-mod prompt_cache;
 mod sse;
 mod types;
 
@@ -9,10 +8,6 @@ pub use client::{
     AnthropicClient, AuthSource, MessageStream, OAuthTokenSet,
 };
 pub use error::ApiError;
-pub use prompt_cache::{
-    CacheBreakEvent, PromptCache, PromptCacheConfig, PromptCachePaths, PromptCacheRecord,
-    PromptCacheStats,
-};
 pub use sse::{parse_frame, SseParser};
 pub use types::{
     ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent, ContentBlockStopEvent,
@@ -21,10 +16,8 @@ pub use types::{
     ToolChoice, ToolDefinition, ToolResultContentBlock, Usage,
 };
 
-#[cfg(test)]
+pub use telemetry::{
-pub(crate) fn test_env_lock() -> std::sync::MutexGuard<'static, ()> {
+    AnalyticsEvent, AnthropicRequestProfile, ClientIdentity, JsonlTelemetrySink,
-    static LOCK: std::sync::OnceLock<std::sync::Mutex<()>> = std::sync::OnceLock::new();
+    MemoryTelemetrySink, SessionTraceRecord, SessionTracer, TelemetryEvent, TelemetrySink,
-    LOCK.get_or_init(|| std::sync::Mutex::new(()))
+    DEFAULT_ANTHROPIC_VERSION,
-        .lock()
+};
-        .unwrap_or_else(std::sync::PoisonError::into_inner)
-}

rust/crates/api/src/prompt_cache.rs

@@ -1,727 +0,0 @@
-use std::fs;
-use std::path::{Path, PathBuf};
-use std::sync::{Arc, Mutex};
-use std::time::{Duration, SystemTime, UNIX_EPOCH};
-
-use serde::{Deserialize, Serialize};
-
-use crate::types::{MessageRequest, MessageResponse, Usage};
-
-const DEFAULT_COMPLETION_TTL_SECS: u64 = 30;
-const DEFAULT_PROMPT_TTL_SECS: u64 = 5 * 60;
-const DEFAULT_BREAK_MIN_DROP: u32 = 2_000;
-const MAX_SANITIZED_LENGTH: usize = 80;
-const REQUEST_FINGERPRINT_VERSION: u32 = 1;
-const REQUEST_FINGERPRINT_PREFIX: &str = "v1";
-const FNV_OFFSET_BASIS: u64 = 0xcbf2_9ce4_8422_2325;
-const FNV_PRIME: u64 = 0x0000_0100_0000_01b3;
-
-#[derive(Debug, Clone)]
-pub struct PromptCacheConfig {
-    pub session_id: String,
-    pub completion_ttl: Duration,
-    pub prompt_ttl: Duration,
-    pub cache_break_min_drop: u32,
-}
-
-impl PromptCacheConfig {
-    #[must_use]
-    pub fn new(session_id: impl Into<String>) -> Self {
-        Self {
-            session_id: session_id.into(),
-            completion_ttl: Duration::from_secs(DEFAULT_COMPLETION_TTL_SECS),
-            prompt_ttl: Duration::from_secs(DEFAULT_PROMPT_TTL_SECS),
-            cache_break_min_drop: DEFAULT_BREAK_MIN_DROP,
-        }
-    }
-}
-
-impl Default for PromptCacheConfig {
-    fn default() -> Self {
-        Self::new("default")
-    }
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
-pub struct PromptCachePaths {
-    pub root: PathBuf,
-    pub session_dir: PathBuf,
-    pub completion_dir: PathBuf,
-    pub session_state_path: PathBuf,
-    pub stats_path: PathBuf,
-}
-
-impl PromptCachePaths {
-    #[must_use]
-    pub fn for_session(session_id: &str) -> Self {
-        let root = base_cache_root();
-        let session_dir = root.join(sanitize_path_segment(session_id));
-        let completion_dir = session_dir.join("completions");
-        Self {
-            root,
-            session_state_path: session_dir.join("session-state.json"),
-            stats_path: session_dir.join("stats.json"),
-            session_dir,
-            completion_dir,
-        }
-    }
-
-    #[must_use]
-    pub fn completion_entry_path(&self, request_hash: &str) -> PathBuf {
-        self.completion_dir.join(format!("{request_hash}.json"))
-    }
-}
-
-#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
-pub struct PromptCacheStats {
-    pub tracked_requests: u64,
-    pub completion_cache_hits: u64,
-    pub completion_cache_misses: u64,
-    pub completion_cache_writes: u64,
-    pub expected_invalidations: u64,
-    pub unexpected_cache_breaks: u64,
-    pub total_cache_creation_input_tokens: u64,
-    pub total_cache_read_input_tokens: u64,
-    pub last_cache_creation_input_tokens: Option<u32>,
-    pub last_cache_read_input_tokens: Option<u32>,
-    pub last_request_hash: Option<String>,
-    pub last_completion_cache_key: Option<String>,
-    pub last_break_reason: Option<String>,
-    pub last_cache_source: Option<String>,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
-pub struct CacheBreakEvent {
-    pub unexpected: bool,
-    pub reason: String,
-    pub previous_cache_read_input_tokens: u32,
-    pub current_cache_read_input_tokens: u32,
-    pub token_drop: u32,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct PromptCacheRecord {
-    pub cache_break: Option<CacheBreakEvent>,
-    pub stats: PromptCacheStats,
-}
-
-#[derive(Debug, Clone)]
-pub struct PromptCache {
-    inner: Arc<Mutex<PromptCacheInner>>,
-}
-
-impl PromptCache {
-    #[must_use]
-    pub fn new(session_id: impl Into<String>) -> Self {
-        Self::with_config(PromptCacheConfig::new(session_id))
-    }
-
-    #[must_use]
-    pub fn with_config(config: PromptCacheConfig) -> Self {
-        let paths = PromptCachePaths::for_session(&config.session_id);
-        let stats = read_json::<PromptCacheStats>(&paths.stats_path).unwrap_or_default();
-        let previous = read_json::<TrackedPromptState>(&paths.session_state_path);
-        Self {
-            inner: Arc::new(Mutex::new(PromptCacheInner {
-                config,
-                paths,
-                stats,
-                previous,
-            })),
-        }
-    }
-
-    #[must_use]
-    pub fn paths(&self) -> PromptCachePaths {
-        self.lock().paths.clone()
-    }
-
-    #[must_use]
-    pub fn stats(&self) -> PromptCacheStats {
-        self.lock().stats.clone()
-    }
-
-    #[must_use]
-    pub fn lookup_completion(&self, request: &MessageRequest) -> Option<MessageResponse> {
-        let request_hash = request_hash_hex(request);
-        let (paths, ttl) = {
-            let inner = self.lock();
-            (inner.paths.clone(), inner.config.completion_ttl)
-        };
-        let entry_path = paths.completion_entry_path(&request_hash);
-        let entry = read_json::<CompletionCacheEntry>(&entry_path);
-        let Some(entry) = entry else {
-            let mut inner = self.lock();
-            inner.stats.completion_cache_misses += 1;
-            inner.stats.last_completion_cache_key = Some(request_hash);
-            persist_state(&inner);
-            return None;
-        };
-
-        if entry.fingerprint_version != current_fingerprint_version() {
-            let mut inner = self.lock();
-            inner.stats.completion_cache_misses += 1;
-            inner.stats.last_completion_cache_key = Some(request_hash.clone());
-            let _ = fs::remove_file(entry_path);
-            persist_state(&inner);
-            return None;
-        }
-
-        let expired = now_unix_secs().saturating_sub(entry.cached_at_unix_secs) >= ttl.as_secs();
-        let mut inner = self.lock();
-        inner.stats.last_completion_cache_key = Some(request_hash.clone());
-        if expired {
-            inner.stats.completion_cache_misses += 1;
-            let _ = fs::remove_file(entry_path);
-            persist_state(&inner);
-            return None;
-        }
-
-        inner.stats.completion_cache_hits += 1;
-        apply_usage_to_stats(
-            &mut inner.stats,
-            &entry.response.usage,
-            &request_hash,
-            "completion-cache",
-        );
-        inner.previous = Some(TrackedPromptState::from_usage(
-            request,
-            &entry.response.usage,
-        ));
-        persist_state(&inner);
-        Some(entry.response)
-    }
-
-    #[must_use]
-    pub fn record_response(
-        &self,
-        request: &MessageRequest,
-        response: &MessageResponse,
-    ) -> PromptCacheRecord {
-        self.record_usage_internal(request, &response.usage, Some(response))
-    }
-
-    #[must_use]
-    pub fn record_usage(&self, request: &MessageRequest, usage: &Usage) -> PromptCacheRecord {
-        self.record_usage_internal(request, usage, None)
-    }
-
-    fn record_usage_internal(
-        &self,
-        request: &MessageRequest,
-        usage: &Usage,
-        response: Option<&MessageResponse>,
-    ) -> PromptCacheRecord {
-        let request_hash = request_hash_hex(request);
-        let mut inner = self.lock();
-        let previous = inner.previous.clone();
-        let current = TrackedPromptState::from_usage(request, usage);
-        let cache_break = detect_cache_break(&inner.config, previous.as_ref(), &current);
-
-        inner.stats.tracked_requests += 1;
-        apply_usage_to_stats(&mut inner.stats, usage, &request_hash, "api-response");
-        if let Some(event) = &cache_break {
-            if event.unexpected {
-                inner.stats.unexpected_cache_breaks += 1;
-            } else {
-                inner.stats.expected_invalidations += 1;
-            }
-            inner.stats.last_break_reason = Some(event.reason.clone());
-        }
-
-        inner.previous = Some(current);
-        if let Some(response) = response {
-            write_completion_entry(&inner.paths, &request_hash, response);
-            inner.stats.completion_cache_writes += 1;
-        }
-        persist_state(&inner);
-
-        PromptCacheRecord {
-            cache_break,
-            stats: inner.stats.clone(),
-        }
-    }
-
-    fn lock(&self) -> std::sync::MutexGuard<'_, PromptCacheInner> {
-        self.inner
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner)
-    }
-}
-
-#[derive(Debug)]
-struct PromptCacheInner {
-    config: PromptCacheConfig,
-    paths: PromptCachePaths,
-    stats: PromptCacheStats,
-    previous: Option<TrackedPromptState>,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-struct CompletionCacheEntry {
-    cached_at_unix_secs: u64,
-    #[serde(default = "current_fingerprint_version")]
-    fingerprint_version: u32,
-    response: MessageResponse,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
-struct TrackedPromptState {
-    observed_at_unix_secs: u64,
-    #[serde(default = "current_fingerprint_version")]
-    fingerprint_version: u32,
-    model_hash: u64,
-    system_hash: u64,
-    tools_hash: u64,
-    messages_hash: u64,
-    cache_read_input_tokens: u32,
-}
-
-impl TrackedPromptState {
-    fn from_usage(request: &MessageRequest, usage: &Usage) -> Self {
-        let hashes = RequestFingerprints::from_request(request);
-        Self {
-            observed_at_unix_secs: now_unix_secs(),
-            fingerprint_version: current_fingerprint_version(),
-            model_hash: hashes.model,
-            system_hash: hashes.system,
-            tools_hash: hashes.tools,
-            messages_hash: hashes.messages,
-            cache_read_input_tokens: usage.cache_read_input_tokens,
-        }
-    }
-}
-
-#[derive(Debug, Clone, Copy)]
-struct RequestFingerprints {
-    model: u64,
-    system: u64,
-    tools: u64,
-    messages: u64,
-}
-
-impl RequestFingerprints {
-    fn from_request(request: &MessageRequest) -> Self {
-        Self {
-            model: hash_serializable(&request.model),
-            system: hash_serializable(&request.system),
-            tools: hash_serializable(&request.tools),
-            messages: hash_serializable(&request.messages),
-        }
-    }
-}
-
-fn detect_cache_break(
-    config: &PromptCacheConfig,
-    previous: Option<&TrackedPromptState>,
-    current: &TrackedPromptState,
-) -> Option<CacheBreakEvent> {
-    let previous = previous?;
-    if previous.fingerprint_version != current.fingerprint_version {
-        return Some(CacheBreakEvent {
-            unexpected: false,
-            reason: format!(
-                "fingerprint version changed (v{} -> v{})",
-                previous.fingerprint_version, current.fingerprint_version
-            ),
-            previous_cache_read_input_tokens: previous.cache_read_input_tokens,
-            current_cache_read_input_tokens: current.cache_read_input_tokens,
-            token_drop: previous
-                .cache_read_input_tokens
-                .saturating_sub(current.cache_read_input_tokens),
-        });
-    }
-    let token_drop = previous
-        .cache_read_input_tokens
-        .saturating_sub(current.cache_read_input_tokens);
-    if token_drop < config.cache_break_min_drop {
-        return None;
-    }
-
-    let mut reasons = Vec::new();
-    if previous.model_hash != current.model_hash {
-        reasons.push("model changed");
-    }
-    if previous.system_hash != current.system_hash {
-        reasons.push("system prompt changed");
-    }
-    if previous.tools_hash != current.tools_hash {
-        reasons.push("tool definitions changed");
-    }
-    if previous.messages_hash != current.messages_hash {
-        reasons.push("message payload changed");
-    }
-
-    let elapsed = current
-        .observed_at_unix_secs
-        .saturating_sub(previous.observed_at_unix_secs);
-
-    let (unexpected, reason) = if reasons.is_empty() {
-        if elapsed > config.prompt_ttl.as_secs() {
-            (
-                false,
-                format!("possible prompt cache TTL expiry after {elapsed}s"),
-            )
-        } else {
-            (
-                true,
-                "cache read tokens dropped while prompt fingerprint remained stable".to_string(),
-            )
-        }
-    } else {
-        (false, reasons.join(", "))
-    };
-
-    Some(CacheBreakEvent {
-        unexpected,
-        reason,
-        previous_cache_read_input_tokens: previous.cache_read_input_tokens,
-        current_cache_read_input_tokens: current.cache_read_input_tokens,
-        token_drop,
-    })
-}
-
-fn apply_usage_to_stats(
-    stats: &mut PromptCacheStats,
-    usage: &Usage,
-    request_hash: &str,
-    source: &str,
-) {
-    stats.total_cache_creation_input_tokens += u64::from(usage.cache_creation_input_tokens);
-    stats.total_cache_read_input_tokens += u64::from(usage.cache_read_input_tokens);
-    stats.last_cache_creation_input_tokens = Some(usage.cache_creation_input_tokens);
-    stats.last_cache_read_input_tokens = Some(usage.cache_read_input_tokens);
-    stats.last_request_hash = Some(request_hash.to_string());
-    stats.last_cache_source = Some(source.to_string());
-}
-
-fn persist_state(inner: &PromptCacheInner) {
-    let _ = ensure_cache_dirs(&inner.paths);
-    let _ = write_json(&inner.paths.stats_path, &inner.stats);
-    if let Some(previous) = &inner.previous {
-        let _ = write_json(&inner.paths.session_state_path, previous);
-    }
-}
-
-fn write_completion_entry(
-    paths: &PromptCachePaths,
-    request_hash: &str,
-    response: &MessageResponse,
-) {
-    let _ = ensure_cache_dirs(paths);
-    let entry = CompletionCacheEntry {
-        cached_at_unix_secs: now_unix_secs(),
-        fingerprint_version: current_fingerprint_version(),
-        response: response.clone(),
-    };
-    let _ = write_json(&paths.completion_entry_path(request_hash), &entry);
-}
-
-fn ensure_cache_dirs(paths: &PromptCachePaths) -> std::io::Result<()> {
-    fs::create_dir_all(&paths.completion_dir)
-}
-
-fn write_json<T: Serialize>(path: &Path, value: &T) -> std::io::Result<()> {
-    let json = serde_json::to_vec_pretty(value)
-        .map_err(|error| std::io::Error::new(std::io::ErrorKind::InvalidData, error))?;
-    fs::write(path, json)
-}
-
-fn read_json<T: for<'de> Deserialize<'de>>(path: &Path) -> Option<T> {
-    let bytes = fs::read(path).ok()?;
-    serde_json::from_slice(&bytes).ok()
-}
-
-fn request_hash_hex(request: &MessageRequest) -> String {
-    format!(
-        "{REQUEST_FINGERPRINT_PREFIX}-{:016x}",
-        hash_serializable(request)
-    )
-}
-
-fn hash_serializable<T: Serialize>(value: &T) -> u64 {
-    let json = serde_json::to_vec(value).unwrap_or_default();
-    stable_hash_bytes(&json)
-}
-
-fn sanitize_path_segment(value: &str) -> String {
-    let sanitized: String = value
-        .chars()
-        .map(|ch| if ch.is_ascii_alphanumeric() { ch } else { '-' })
-        .collect();
-    if sanitized.len() <= MAX_SANITIZED_LENGTH {
-        return sanitized;
-    }
-    let suffix = format!("-{:x}", hash_string(value));
-    format!(
-        "{}{}",
-        &sanitized[..MAX_SANITIZED_LENGTH.saturating_sub(suffix.len())],
-        suffix
-    )
-}
-
-fn hash_string(value: &str) -> u64 {
-    stable_hash_bytes(value.as_bytes())
-}
-
-fn base_cache_root() -> PathBuf {
-    if let Some(config_home) = std::env::var_os("CLAUDE_CONFIG_HOME") {
-        return PathBuf::from(config_home)
-            .join("cache")
-            .join("prompt-cache");
-    }
-    if let Some(home) = std::env::var_os("HOME") {
-        return PathBuf::from(home)
-            .join(".claude")
-            .join("cache")
-            .join("prompt-cache");
-    }
-    std::env::temp_dir().join("claude-prompt-cache")
-}
-
-fn now_unix_secs() -> u64 {
-    SystemTime::now()
-        .duration_since(UNIX_EPOCH)
-        .map_or(0, |duration| duration.as_secs())
-}
-
-const fn current_fingerprint_version() -> u32 {
-    REQUEST_FINGERPRINT_VERSION
-}
-
-fn stable_hash_bytes(bytes: &[u8]) -> u64 {
-    let mut hash = FNV_OFFSET_BASIS;
-    for byte in bytes {
-        hash ^= u64::from(*byte);
-        hash = hash.wrapping_mul(FNV_PRIME);
-    }
-    hash
-}
-
-#[cfg(test)]
-mod tests {
-    use std::time::{Duration, SystemTime, UNIX_EPOCH};
-
-    use super::{
-        detect_cache_break, read_json, request_hash_hex, sanitize_path_segment, PromptCache,
-        PromptCacheConfig, PromptCachePaths, TrackedPromptState, REQUEST_FINGERPRINT_PREFIX,
-    };
-    use crate::test_env_lock;
-    use crate::types::{InputMessage, MessageRequest, MessageResponse, OutputContentBlock, Usage};
-
-    #[test]
-    fn path_builder_sanitizes_session_identifier() {
-        let paths = PromptCachePaths::for_session("session:/with spaces");
-        let session_dir = paths
-            .session_dir
-            .file_name()
-            .and_then(|value| value.to_str())
-            .expect("session dir name");
-        assert_eq!(session_dir, "session--with-spaces");
-        assert!(paths.completion_dir.ends_with("completions"));
-        assert!(paths.stats_path.ends_with("stats.json"));
-        assert!(paths.session_state_path.ends_with("session-state.json"));
-    }
-
-    #[test]
-    fn request_fingerprint_drives_unexpected_break_detection() {
-        let request = sample_request("same");
-        let previous = TrackedPromptState::from_usage(
-            &request,
-            &Usage {
-                input_tokens: 0,
-                cache_creation_input_tokens: 0,
-                cache_read_input_tokens: 6_000,
-                output_tokens: 0,
-            },
-        );
-        let current = TrackedPromptState::from_usage(
-            &request,
-            &Usage {
-                input_tokens: 0,
-                cache_creation_input_tokens: 0,
-                cache_read_input_tokens: 1_000,
-                output_tokens: 0,
-            },
-        );
-        let event = detect_cache_break(&PromptCacheConfig::default(), Some(&previous), &current)
-            .expect("break should be detected");
-        assert!(event.unexpected);
-        assert!(event.reason.contains("stable"));
-    }
-
-    #[test]
-    fn changed_prompt_marks_break_as_expected() {
-        let previous_request = sample_request("first");
-        let current_request = sample_request("second");
-        let previous = TrackedPromptState::from_usage(
-            &previous_request,
-            &Usage {
-                input_tokens: 0,
-                cache_creation_input_tokens: 0,
-                cache_read_input_tokens: 6_000,
-                output_tokens: 0,
-            },
-        );
-        let current = TrackedPromptState::from_usage(
-            &current_request,
-            &Usage {
-                input_tokens: 0,
-                cache_creation_input_tokens: 0,
-                cache_read_input_tokens: 1_000,
-                output_tokens: 0,
-            },
-        );
-        let event = detect_cache_break(&PromptCacheConfig::default(), Some(&previous), &current)
-            .expect("break should be detected");
-        assert!(!event.unexpected);
-        assert!(event.reason.contains("message payload changed"));
-    }
-
-    #[test]
-    fn completion_cache_round_trip_persists_recent_response() {
-        let _guard = test_env_lock();
-        let temp_root = std::env::temp_dir().join(format!(
-            "prompt-cache-test-{}-{}",
-            std::process::id(),
-            SystemTime::now()
-                .duration_since(UNIX_EPOCH)
-                .expect("time")
-                .as_nanos()
-        ));
-        std::env::set_var("CLAUDE_CONFIG_HOME", &temp_root);
-        let cache = PromptCache::new("unit-test-session");
-        let request = sample_request("cache me");
-        let response = sample_response(42, 12, "cached");
-
-        assert!(cache.lookup_completion(&request).is_none());
-        let record = cache.record_response(&request, &response);
-        assert!(record.cache_break.is_none());
-
-        let cached = cache
-            .lookup_completion(&request)
-            .expect("cached response should load");
-        assert_eq!(cached.content, response.content);
-
-        let stats = cache.stats();
-        assert_eq!(stats.completion_cache_hits, 1);
-        assert_eq!(stats.completion_cache_misses, 1);
-        assert_eq!(stats.completion_cache_writes, 1);
-
-        let persisted = read_json::<super::PromptCacheStats>(&cache.paths().stats_path)
-            .expect("stats should persist");
-        assert_eq!(persisted.completion_cache_hits, 1);
-
-        std::fs::remove_dir_all(temp_root).expect("cleanup temp root");
-        std::env::remove_var("CLAUDE_CONFIG_HOME");
-    }
-
-    #[test]
-    fn distinct_requests_do_not_collide_in_completion_cache() {
-        let _guard = test_env_lock();
-        let temp_root = std::env::temp_dir().join(format!(
-            "prompt-cache-distinct-{}-{}",
-            std::process::id(),
-            SystemTime::now()
-                .duration_since(UNIX_EPOCH)
-                .expect("time")
-                .as_nanos()
-        ));
-        std::env::set_var("CLAUDE_CONFIG_HOME", &temp_root);
-        let cache = PromptCache::new("distinct-request-session");
-        let first_request = sample_request("first");
-        let second_request = sample_request("second");
-
-        let response = sample_response(42, 12, "cached");
-        let _ = cache.record_response(&first_request, &response);
-
-        assert!(cache.lookup_completion(&second_request).is_none());
-
-        std::fs::remove_dir_all(temp_root).expect("cleanup temp root");
-        std::env::remove_var("CLAUDE_CONFIG_HOME");
-    }
-
-    #[test]
-    fn expired_completion_entries_are_not_reused() {
-        let _guard = test_env_lock();
-        let temp_root = std::env::temp_dir().join(format!(
-            "prompt-cache-expired-{}-{}",
-            std::process::id(),
-            SystemTime::now()
-                .duration_since(UNIX_EPOCH)
-                .expect("time")
-                .as_nanos()
-        ));
-        std::env::set_var("CLAUDE_CONFIG_HOME", &temp_root);
-        let cache = PromptCache::with_config(PromptCacheConfig {
-            session_id: "expired-session".to_string(),
-            completion_ttl: Duration::ZERO,
-            ..PromptCacheConfig::default()
-        });
-        let request = sample_request("expire me");
-        let response = sample_response(7, 3, "stale");
-
-        let _ = cache.record_response(&request, &response);
-
-        assert!(cache.lookup_completion(&request).is_none());
-        let stats = cache.stats();
-        assert_eq!(stats.completion_cache_hits, 0);
-        assert_eq!(stats.completion_cache_misses, 1);
-
-        std::fs::remove_dir_all(temp_root).expect("cleanup temp root");
-        std::env::remove_var("CLAUDE_CONFIG_HOME");
-    }
-
-    #[test]
-    fn sanitize_path_caps_long_values() {
-        let long_value = "x".repeat(200);
-        let sanitized = sanitize_path_segment(&long_value);
-        assert!(sanitized.len() <= 80);
-    }
-
-    #[test]
-    fn request_hashes_are_versioned_and_stable() {
-        let request = sample_request("stable");
-        let first = request_hash_hex(&request);
-        let second = request_hash_hex(&request);
-        assert_eq!(first, second);
-        assert!(first.starts_with(REQUEST_FINGERPRINT_PREFIX));
-    }
-
-    fn sample_request(text: &str) -> MessageRequest {
-        MessageRequest {
-            model: "claude-3-7-sonnet-latest".to_string(),
-            max_tokens: 64,
-            messages: vec![InputMessage::user_text(text)],
-            system: Some("system".to_string()),
-            tools: None,
-            tool_choice: None,
-            stream: false,
-        }
-    }
-
-    fn sample_response(
-        cache_read_input_tokens: u32,
-        output_tokens: u32,
-        text: &str,
-    ) -> MessageResponse {
-        MessageResponse {
-            id: "msg_test".to_string(),
-            kind: "message".to_string(),
-            role: "assistant".to_string(),
-            content: vec![OutputContentBlock::Text {
-                text: text.to_string(),
-            }],
-            model: "claude-3-7-sonnet-latest".to_string(),
-            stop_reason: Some("end_turn".to_string()),
-            stop_sequence: None,
-            usage: Usage {
-                input_tokens: 10,
-                cache_creation_input_tokens: 5,
-                cache_read_input_tokens,
-                output_tokens,
-            },
-            request_id: Some("req_test".to_string()),
-        }
-    }
-}

rust/crates/api/src/types.rs

@@ -1,3 +1,4 @@
+use runtime::{pricing_for_model, TokenUsage, UsageCostEstimate};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
@@ -150,7 +151,29 @@ pub struct Usage {
 impl Usage {
     #[must_use]
     pub const fn total_tokens(&self) -> u32 {
-        self.input_tokens + self.output_tokens
+        self.input_tokens
+            + self.output_tokens
+            + self.cache_creation_input_tokens
+            + self.cache_read_input_tokens
+    }
+
+    #[must_use]
+    pub const fn token_usage(&self) -> TokenUsage {
+        TokenUsage {
+            input_tokens: self.input_tokens,
+            output_tokens: self.output_tokens,
+            cache_creation_input_tokens: self.cache_creation_input_tokens,
+            cache_read_input_tokens: self.cache_read_input_tokens,
+        }
+    }
+
+    #[must_use]
+    pub fn estimated_cost_usd(&self, model: &str) -> UsageCostEstimate {
+        let usage = self.token_usage();
+        pricing_for_model(model).map_or_else(
+            || usage.estimate_cost_usd(),
+            |pricing| usage.estimate_cost_usd_with_pricing(pricing),
+        )
     }
 }
 
@@ -210,3 +233,47 @@ pub enum StreamEvent {
     ContentBlockStop(ContentBlockStopEvent),
     MessageStop(MessageStopEvent),
 }
+
+#[cfg(test)]
+mod tests {
+    use runtime::format_usd;
+
+    use super::{MessageResponse, Usage};
+
+    #[test]
+    fn usage_total_tokens_includes_cache_tokens() {
+        let usage = Usage {
+            input_tokens: 10,
+            cache_creation_input_tokens: 2,
+            cache_read_input_tokens: 3,
+            output_tokens: 4,
+        };
+
+        assert_eq!(usage.total_tokens(), 19);
+        assert_eq!(usage.token_usage().total_tokens(), 19);
+    }
+
+    #[test]
+    fn message_response_estimates_cost_from_model_usage() {
+        let response = MessageResponse {
+            id: "msg_cost".to_string(),
+            kind: "message".to_string(),
+            role: "assistant".to_string(),
+            content: Vec::new(),
+            model: "claude-sonnet-4-20250514".to_string(),
+            stop_reason: Some("end_turn".to_string()),
+            stop_sequence: None,
+            usage: Usage {
+                input_tokens: 1_000_000,
+                cache_creation_input_tokens: 100_000,
+                cache_read_input_tokens: 200_000,
+                output_tokens: 500_000,
+            },
+            request_id: None,
+        };
+
+        let cost = response.usage.estimated_cost_usd(&response.model);
+        assert_eq!(format_usd(cost.total_cost_usd()), "$54.6750");
+        assert_eq!(response.total_tokens(), 1_800_000);
+    }
+}

rust/crates/api/tests/client_integration.rs

@@ -1,25 +1,18 @@
 use std::collections::HashMap;
 use std::sync::Arc;
-use std::sync::{Mutex as StdMutex, OnceLock};
 use std::time::Duration;
 
 use api::{
     AnthropicClient, ApiError, ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent,
     InputContentBlock, InputMessage, MessageDeltaEvent, MessageRequest, OutputContentBlock,
-    PromptCache, StreamEvent, ToolChoice, ToolDefinition,
+    StreamEvent, ToolChoice, ToolDefinition,
 };
 use serde_json::json;
+use telemetry::{ClientIdentity, MemoryTelemetrySink, SessionTracer, TelemetryEvent};
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::TcpListener;
 use tokio::sync::Mutex;
 
-fn env_lock() -> std::sync::MutexGuard<'static, ()> {
-    static LOCK: OnceLock<StdMutex<()>> = OnceLock::new();
-    LOCK.get_or_init(|| StdMutex::new(()))
-        .lock()
-        .unwrap_or_else(std::sync::PoisonError::into_inner)
-}
-
 #[tokio::test]
 async fn send_message_posts_json_and_parses_response() {
     let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
@@ -53,8 +46,6 @@ async fn send_message_posts_json_and_parses_response() {
     assert_eq!(response.id, "msg_test");
     assert_eq!(response.total_tokens(), 16);
     assert_eq!(response.request_id.as_deref(), Some("req_body_123"));
-    assert_eq!(response.usage.cache_creation_input_tokens, 0);
-    assert_eq!(response.usage.cache_read_input_tokens, 0);
     assert_eq!(
         response.content,
         vec![OutputContentBlock::Text {
@@ -74,6 +65,18 @@ async fn send_message_posts_json_and_parses_response() {
         request.headers.get("authorization").map(String::as_str),
         Some("Bearer proxy-token")
     );
+    assert_eq!(
+        request.headers.get("anthropic-version").map(String::as_str),
+        Some("2023-06-01")
+    );
+    assert_eq!(
+        request.headers.get("user-agent").map(String::as_str),
+        Some("claude-code/0.1.0")
+    );
+    assert_eq!(
+        request.headers.get("anthropic-beta").map(String::as_str),
+        Some("claude-code-20250219,prompt-caching-scope-2026-01-05")
+    );
     let body: serde_json::Value =
         serde_json::from_str(&request.body).expect("request body should be json");
     assert_eq!(
@@ -83,58 +86,123 @@ async fn send_message_posts_json_and_parses_response() {
     assert!(body.get("stream").is_none());
     assert_eq!(body["tools"][0]["name"], json!("get_weather"));
     assert_eq!(body["tool_choice"]["type"], json!("auto"));
+    assert_eq!(
+        body["betas"],
+        json!(["claude-code-20250219", "prompt-caching-scope-2026-01-05"])
+    );
 }
 
 #[tokio::test]
-async fn send_message_parses_prompt_cache_token_usage_from_response() {
+async fn send_message_applies_request_profile_and_records_telemetry() {
     let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
-    let body = concat!(
+    let server = spawn_server(
+        state.clone(),
+        vec![http_response_with_headers(
+            "200 OK",
+            "application/json",
+            concat!(
                 "{",
-        "\"id\":\"msg_cache_tokens\",",
+                "\"id\":\"msg_profile\",",
                 "\"type\":\"message\",",
                 "\"role\":\"assistant\",",
-        "\"content\":[{\"type\":\"text\",\"text\":\"Cache tokens\"}],",
+                "\"content\":[{\"type\":\"text\",\"text\":\"ok\"}],",
                 "\"model\":\"claude-3-7-sonnet-latest\",",
                 "\"stop_reason\":\"end_turn\",",
                 "\"stop_sequence\":null,",
-        "\"usage\":{\"input_tokens\":12,\"cache_creation_input_tokens\":321,\"cache_read_input_tokens\":654,\"output_tokens\":4}",
+                "\"usage\":{\"input_tokens\":1,\"cache_creation_input_tokens\":2,\"cache_read_input_tokens\":3,\"output_tokens\":1}",
                 "}"
-    );
+            ),
-    let server = spawn_server(
+            &[("request-id", "req_profile_123")],
-        state,
+        )],
-        vec![http_response("200 OK", "application/json", body)],
     )
     .await;
+    let sink = Arc::new(MemoryTelemetrySink::default());
+
+    let client = AnthropicClient::new("test-key")
+        .with_base_url(server.base_url())
+        .with_client_identity(ClientIdentity::new("claude-code", "9.9.9").with_runtime("rust-cli"))
+        .with_beta("tools-2026-04-01")
+        .with_extra_body_param("metadata", json!({"source": "clawd-code"}))
+        .with_session_tracer(SessionTracer::new("session-telemetry", sink.clone()));
 
-    let client = AnthropicClient::new("test-key").with_base_url(server.base_url());
     let response = client
         .send_message(&sample_request(false))
         .await
         .expect("request should succeed");
 
-    assert_eq!(response.usage.input_tokens, 12);
+    assert_eq!(response.request_id.as_deref(), Some("req_profile_123"));
-    assert_eq!(response.usage.cache_creation_input_tokens, 321);
+
-    assert_eq!(response.usage.cache_read_input_tokens, 654);
+    let captured = state.lock().await;
-    assert_eq!(response.usage.output_tokens, 4);
+    let request = captured.first().expect("server should capture request");
+    assert_eq!(
+        request.headers.get("anthropic-beta").map(String::as_str),
+        Some("claude-code-20250219,prompt-caching-scope-2026-01-05,tools-2026-04-01")
+    );
+    assert_eq!(
+        request.headers.get("user-agent").map(String::as_str),
+        Some("claude-code/9.9.9")
+    );
+    let body: serde_json::Value =
+        serde_json::from_str(&request.body).expect("request body should be json");
+    assert_eq!(body["metadata"]["source"], json!("clawd-code"));
+    assert_eq!(
+        body["betas"],
+        json!([
+            "claude-code-20250219",
+            "prompt-caching-scope-2026-01-05",
+            "tools-2026-04-01"
+        ])
+    );
+
+    let events = sink.events();
+    assert_eq!(events.len(), 6);
+    assert!(matches!(
+        &events[0],
+        TelemetryEvent::HttpRequestStarted {
+            session_id,
+            attempt: 1,
+            method,
+            path,
+            ..
+        } if session_id == "session-telemetry" && method == "POST" && path == "/v1/messages"
+    ));
+    assert!(matches!(
+        &events[1],
+        TelemetryEvent::SessionTrace(trace) if trace.name == "http_request_started"
+    ));
+    assert!(matches!(
+        &events[2],
+        TelemetryEvent::HttpRequestSucceeded {
+            request_id,
+            status: 200,
+            ..
+        } if request_id.as_deref() == Some("req_profile_123")
+    ));
+    assert!(matches!(
+        &events[3],
+        TelemetryEvent::SessionTrace(trace) if trace.name == "http_request_succeeded"
+    ));
+    assert!(matches!(
+        &events[4],
+        TelemetryEvent::Analytics(event)
+            if event.namespace == "api"
+                && event.action == "message_usage"
+                && event.properties.get("request_id") == Some(&json!("req_profile_123"))
+                && event.properties.get("total_tokens") == Some(&json!(7))
+                && event.properties.get("estimated_cost_usd") == Some(&json!("$0.0001"))
+    ));
+    assert!(matches!(
+        &events[5],
+        TelemetryEvent::SessionTrace(trace) if trace.name == "analytics"
+    ));
 }
 
 #[tokio::test]
-#[allow(clippy::await_holding_lock)]
 async fn stream_message_parses_sse_events_with_tool_use() {
-    let _guard = env_lock();
-    let temp_root = std::env::temp_dir().join(format!(
-        "api-stream-cache-{}-{}",
-        std::process::id(),
-        std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .expect("time")
-            .as_nanos()
-    ));
-    std::env::set_var("CLAUDE_CONFIG_HOME", &temp_root);
     let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
     let sse = concat!(
         "event: message_start\n",
-        "data: {\"type\":\"message_start\",\"message\":{\"id\":\"msg_stream\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":null,\"stop_sequence\":null,\"usage\":{\"input_tokens\":8,\"cache_creation_input_tokens\":13,\"cache_read_input_tokens\":21,\"output_tokens\":0}}}\n\n",
+        "data: {\"type\":\"message_start\",\"message\":{\"id\":\"msg_stream\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":null,\"stop_sequence\":null,\"usage\":{\"input_tokens\":8,\"output_tokens\":0}}}\n\n",
         "event: content_block_start\n",
         "data: {\"type\":\"content_block_start\",\"index\":0,\"content_block\":{\"type\":\"tool_use\",\"id\":\"toolu_123\",\"name\":\"get_weather\",\"input\":{}}}\n\n",
         "event: content_block_delta\n",
@@ -142,7 +210,7 @@ async fn stream_message_parses_sse_events_with_tool_use() {
         "event: content_block_stop\n",
         "data: {\"type\":\"content_block_stop\",\"index\":0}\n\n",
         "event: message_delta\n",
-        "data: {\"type\":\"message_delta\",\"delta\":{\"stop_reason\":\"tool_use\",\"stop_sequence\":null},\"usage\":{\"input_tokens\":8,\"cache_creation_input_tokens\":34,\"cache_read_input_tokens\":55,\"output_tokens\":1}}\n\n",
+        "data: {\"type\":\"message_delta\",\"delta\":{\"stop_reason\":\"tool_use\",\"stop_sequence\":null},\"usage\":{\"input_tokens\":8,\"output_tokens\":1}}\n\n",
         "event: message_stop\n",
         "data: {\"type\":\"message_stop\"}\n\n",
         "data: [DONE]\n\n"
@@ -160,8 +228,7 @@ async fn stream_message_parses_sse_events_with_tool_use() {
 
     let client = AnthropicClient::new("test-key")
         .with_auth_token(Some("proxy-token".to_string()))
-        .with_base_url(server.base_url())
+        .with_base_url(server.base_url());
-        .with_prompt_cache(PromptCache::new("stream-session"));
     let mut stream = client
         .stream_message(&sample_request(false))
         .await
@@ -215,20 +282,6 @@ async fn stream_message_parses_sse_events_with_tool_use() {
     let captured = state.lock().await;
     let request = captured.first().expect("server should capture request");
     assert!(request.body.contains("\"stream\":true"));
-
-    let cache_stats = client
-        .prompt_cache_stats()
-        .expect("prompt cache stats should exist");
-    assert_eq!(cache_stats.tracked_requests, 1);
-    assert_eq!(cache_stats.last_cache_creation_input_tokens, Some(34));
-    assert_eq!(cache_stats.last_cache_read_input_tokens, Some(55));
-    assert_eq!(
-        cache_stats.last_cache_source.as_deref(),
-        Some("api-response")
-    );
-
-    std::fs::remove_dir_all(temp_root).expect("cleanup temp root");
-    std::env::remove_var("CLAUDE_CONFIG_HOME");
 }
 
 #[tokio::test]
@@ -312,121 +365,6 @@ async fn surfaces_retry_exhaustion_for_persistent_retryable_errors() {
     }
 }
 
-#[tokio::test]
-#[allow(clippy::await_holding_lock)]
-async fn send_message_reuses_recent_completion_cache_entries() {
-    let _guard = env_lock();
-    let temp_root = std::env::temp_dir().join(format!(
-        "api-prompt-cache-{}-{}",
-        std::process::id(),
-        std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .expect("time")
-            .as_nanos()
-    ));
-    std::env::set_var("CLAUDE_CONFIG_HOME", &temp_root);
-
-    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
-    let server = spawn_server(
-        state.clone(),
-        vec![http_response(
-            "200 OK",
-            "application/json",
-            "{\"id\":\"msg_cached\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"Cached once\"}],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":\"end_turn\",\"stop_sequence\":null,\"usage\":{\"input_tokens\":3,\"cache_creation_input_tokens\":5,\"cache_read_input_tokens\":4000,\"output_tokens\":2}}",
-        )],
-    )
-    .await;
-
-    let client = AnthropicClient::new("test-key")
-        .with_base_url(server.base_url())
-        .with_prompt_cache(PromptCache::new("integration-session"));
-
-    let first = client
-        .send_message(&sample_request(false))
-        .await
-        .expect("first request should succeed");
-    let second = client
-        .send_message(&sample_request(false))
-        .await
-        .expect("second request should reuse cache");
-
-    assert_eq!(first.content, second.content);
-    assert_eq!(state.lock().await.len(), 1);
-
-    let cache_stats = client
-        .prompt_cache_stats()
-        .expect("prompt cache stats should exist");
-    assert_eq!(cache_stats.completion_cache_hits, 1);
-    assert_eq!(cache_stats.completion_cache_misses, 1);
-    assert_eq!(cache_stats.completion_cache_writes, 1);
-
-    std::fs::remove_dir_all(temp_root).expect("cleanup temp root");
-    std::env::remove_var("CLAUDE_CONFIG_HOME");
-}
-
-#[tokio::test]
-#[allow(clippy::await_holding_lock)]
-async fn send_message_tracks_unexpected_prompt_cache_breaks() {
-    let _guard = env_lock();
-    let temp_root = std::env::temp_dir().join(format!(
-        "api-prompt-break-{}-{}",
-        std::process::id(),
-        std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .expect("time")
-            .as_nanos()
-    ));
-    std::env::set_var("CLAUDE_CONFIG_HOME", &temp_root);
-
-    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
-    let server = spawn_server(
-        state,
-        vec![
-            http_response(
-                "200 OK",
-                "application/json",
-                "{\"id\":\"msg_one\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"One\"}],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":\"end_turn\",\"stop_sequence\":null,\"usage\":{\"input_tokens\":3,\"cache_creation_input_tokens\":5,\"cache_read_input_tokens\":6000,\"output_tokens\":2}}",
-            ),
-            http_response(
-                "200 OK",
-                "application/json",
-                "{\"id\":\"msg_two\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"Two\"}],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":\"end_turn\",\"stop_sequence\":null,\"usage\":{\"input_tokens\":3,\"cache_creation_input_tokens\":0,\"cache_read_input_tokens\":1000,\"output_tokens\":2}}",
-            ),
-        ],
-    )
-    .await;
-
-    let request = sample_request(false);
-    let client = AnthropicClient::new("test-key")
-        .with_base_url(server.base_url())
-        .with_prompt_cache(PromptCache::with_config(api::PromptCacheConfig {
-            session_id: "break-session".to_string(),
-            completion_ttl: Duration::from_secs(0),
-            ..api::PromptCacheConfig::default()
-        }));
-
-    client
-        .send_message(&request)
-        .await
-        .expect("first response should succeed");
-    client
-        .send_message(&request)
-        .await
-        .expect("second response should succeed");
-
-    let cache_stats = client
-        .prompt_cache_stats()
-        .expect("prompt cache stats should exist");
-    assert_eq!(cache_stats.unexpected_cache_breaks, 1);
-    assert_eq!(
-        cache_stats.last_break_reason.as_deref(),
-        Some("cache read tokens dropped while prompt fingerprint remained stable")
-    );
-
-    std::fs::remove_dir_all(temp_root).expect("cleanup temp root");
-    std::env::remove_var("CLAUDE_CONFIG_HOME");
-}
-
 #[tokio::test]
 #[ignore = "requires ANTHROPIC_API_KEY and network access"]
 async fn live_stream_smoke_test() {

rust/crates/runtime/Cargo.toml

@@ -11,6 +11,7 @@ glob = "0.3"
 regex = "1"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+telemetry = { path = "../telemetry" }
 tokio = { version = "1", features = ["io-util", "macros", "process", "rt", "rt-multi-thread", "time"] }
 walkdir = "2"
 

rust/crates/runtime/src/conversation.rs

@@ -1,6 +1,9 @@
 use std::collections::BTreeMap;
 use std::fmt::{Display, Formatter};
 
+use serde_json::{Map, Value};
+use telemetry::SessionTracer;
+
 use crate::compact::{
     compact_session, estimate_session_tokens, CompactionConfig, CompactionResult,
 };
@@ -25,19 +28,9 @@ pub enum AssistantEvent {
         input: String,
     },
     Usage(TokenUsage),
-    PromptCache(PromptCacheEvent),
     MessageStop,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct PromptCacheEvent {
-    pub unexpected: bool,
-    pub reason: String,
-    pub previous_cache_read_input_tokens: u32,
-    pub current_cache_read_input_tokens: u32,
-    pub token_drop: u32,
-}
-
 pub trait ApiClient {
     fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError>;
 }
@@ -94,7 +87,6 @@ impl std::error::Error for RuntimeError {}
 pub struct TurnSummary {
     pub assistant_messages: Vec<ConversationMessage>,
     pub tool_results: Vec<ConversationMessage>,
-    pub prompt_cache_events: Vec<PromptCacheEvent>,
     pub iterations: usize,
     pub usage: TokenUsage,
 }
@@ -108,6 +100,7 @@ pub struct ConversationRuntime<C, T> {
     max_iterations: usize,
     usage_tracker: UsageTracker,
     hook_runner: HookRunner,
+    session_tracer: Option<SessionTracer>,
 }
 
 impl<C, T> ConversationRuntime<C, T>
@@ -152,6 +145,7 @@ where
             max_iterations: usize::MAX,
             usage_tracker,
             hook_runner: HookRunner::from_feature_config(feature_config),
+            session_tracer: None,
         }
     }
 
@@ -161,39 +155,59 @@ where
         self
     }
 
+    #[must_use]
+    pub fn with_session_tracer(mut self, session_tracer: SessionTracer) -> Self {
+        self.session_tracer = Some(session_tracer);
+        self
+    }
+
+    #[allow(clippy::too_many_lines)]
     pub fn run_turn(
         &mut self,
         user_input: impl Into<String>,
         mut prompter: Option<&mut dyn PermissionPrompter>,
     ) -> Result<TurnSummary, RuntimeError> {
+        let user_input = user_input.into();
+        self.record_turn_started(&user_input);
         self.session
             .messages
-            .push(ConversationMessage::user_text(user_input.into()));
+            .push(ConversationMessage::user_text(user_input));
 
         let mut assistant_messages = Vec::new();
         let mut tool_results = Vec::new();
-        let mut prompt_cache_events = Vec::new();
         let mut iterations = 0;
 
         loop {
             iterations += 1;
             if iterations > self.max_iterations {
-                return Err(RuntimeError::new(
+                let error = RuntimeError::new(
                     "conversation loop exceeded the maximum number of iterations",
-                ));
+                );
+                self.record_turn_failed(iterations, &error);
+                return Err(error);
             }
 
             let request = ApiRequest {
                 system_prompt: self.system_prompt.clone(),
                 messages: self.session.messages.clone(),
             };
-            let events = self.api_client.stream(request)?;
+            let events = match self.api_client.stream(request) {
-            let (assistant_message, usage, turn_prompt_cache_events) =
+                Ok(events) => events,
-                build_assistant_message(events)?;
+                Err(error) => {
+                    self.record_turn_failed(iterations, &error);
+                    return Err(error);
+                }
+            };
+            let (assistant_message, usage) = match build_assistant_message(events) {
+                Ok(result) => result,
+                Err(error) => {
+                    self.record_turn_failed(iterations, &error);
+                    return Err(error);
+                }
+            };
             if let Some(usage) = usage {
                 self.usage_tracker.record(usage);
             }
-            prompt_cache_events.extend(turn_prompt_cache_events);
             let pending_tool_uses = assistant_message
                 .blocks
                 .iter()
@@ -204,6 +218,11 @@ where
                     _ => None,
                 })
                 .collect::<Vec<_>>();
+            self.record_assistant_iteration(
+                iterations,
+                &assistant_message,
+                pending_tool_uses.len(),
+            );
 
             self.session.messages.push(assistant_message.clone());
             assistant_messages.push(assistant_message);
@@ -213,6 +232,7 @@ where
             }
 
             for (tool_use_id, tool_name, input) in pending_tool_uses {
+                self.record_tool_started(iterations, &tool_name);
                 let permission_outcome = if let Some(prompt) = prompter.as_mut() {
                     self.permission_policy
                         .authorize(&tool_name, &input, Some(*prompt))
@@ -263,18 +283,20 @@ where
                         ConversationMessage::tool_result(tool_use_id, tool_name, reason, true)
                     }
                 };
+                self.record_tool_finished(iterations, &result_message);
                 self.session.messages.push(result_message.clone());
                 tool_results.push(result_message);
             }
         }
 
-        Ok(TurnSummary {
+        let summary = TurnSummary {
             assistant_messages,
             tool_results,
-            prompt_cache_events,
             iterations,
             usage: self.usage_tracker.cumulative_usage(),
-        })
+        };
+        self.record_turn_completed(&summary);
+        Ok(summary)
     }
 
     #[must_use]
@@ -301,21 +323,133 @@ where
     pub fn into_session(self) -> Session {
         self.session
     }
+
+    fn record_turn_started(&self, user_input: &str) {
+        if let Some(tracer) = &self.session_tracer {
+            let mut attributes = Map::new();
+            attributes.insert(
+                "message_count_before".to_string(),
+                Value::from(u64::try_from(self.session.messages.len()).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "input_chars".to_string(),
+                Value::from(u64::try_from(user_input.chars().count()).unwrap_or(u64::MAX)),
+            );
+            tracer.record("turn_started", attributes);
+        }
+    }
+
+    fn record_assistant_iteration(
+        &self,
+        iteration: usize,
+        assistant_message: &ConversationMessage,
+        pending_tool_count: usize,
+    ) {
+        if let Some(tracer) = &self.session_tracer {
+            let mut attributes = Map::new();
+            attributes.insert(
+                "iteration".to_string(),
+                Value::from(u64::try_from(iteration).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "block_count".to_string(),
+                Value::from(u64::try_from(assistant_message.blocks.len()).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "pending_tool_count".to_string(),
+                Value::from(u64::try_from(pending_tool_count).unwrap_or(u64::MAX)),
+            );
+            tracer.record("assistant_iteration_completed", attributes);
+        }
+    }
+
+    fn record_tool_started(&self, iteration: usize, tool_name: &str) {
+        if let Some(tracer) = &self.session_tracer {
+            let mut attributes = Map::new();
+            attributes.insert(
+                "iteration".to_string(),
+                Value::from(u64::try_from(iteration).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "tool_name".to_string(),
+                Value::String(tool_name.to_string()),
+            );
+            tracer.record("tool_execution_started", attributes);
+        }
+    }
+
+    fn record_tool_finished(&self, iteration: usize, result_message: &ConversationMessage) {
+        let Some(tracer) = &self.session_tracer else {
+            return;
+        };
+        let Some(ContentBlock::ToolResult {
+            tool_name,
+            is_error,
+            output,
+            ..
+        }) = result_message.blocks.first()
+        else {
+            return;
+        };
+        let mut attributes = Map::new();
+        attributes.insert(
+            "iteration".to_string(),
+            Value::from(u64::try_from(iteration).unwrap_or(u64::MAX)),
+        );
+        attributes.insert("tool_name".to_string(), Value::String(tool_name.clone()));
+        attributes.insert("is_error".to_string(), Value::Bool(*is_error));
+        attributes.insert(
+            "output_chars".to_string(),
+            Value::from(u64::try_from(output.chars().count()).unwrap_or(u64::MAX)),
+        );
+        tracer.record("tool_execution_finished", attributes);
+    }
+
+    fn record_turn_completed(&self, summary: &TurnSummary) {
+        if let Some(tracer) = &self.session_tracer {
+            let mut attributes = Map::new();
+            attributes.insert(
+                "assistant_message_count".to_string(),
+                Value::from(u64::try_from(summary.assistant_messages.len()).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "tool_result_count".to_string(),
+                Value::from(u64::try_from(summary.tool_results.len()).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "iterations".to_string(),
+                Value::from(u64::try_from(summary.iterations).unwrap_or(u64::MAX)),
+            );
+            attributes.insert(
+                "total_input_tokens".to_string(),
+                Value::from(summary.usage.input_tokens),
+            );
+            attributes.insert(
+                "total_output_tokens".to_string(),
+                Value::from(summary.usage.output_tokens),
+            );
+            tracer.record("turn_completed", attributes);
+        }
+    }
+
+    fn record_turn_failed(&self, iteration: usize, error: &RuntimeError) {
+        if let Some(tracer) = &self.session_tracer {
+            let mut attributes = Map::new();
+            attributes.insert(
+                "iteration".to_string(),
+                Value::from(u64::try_from(iteration).unwrap_or(u64::MAX)),
+            );
+            attributes.insert("error".to_string(), Value::String(error.to_string()));
+            tracer.record("turn_failed", attributes);
+        }
+    }
 }
 
 fn build_assistant_message(
     events: Vec<AssistantEvent>,
-) -> Result<
+) -> Result<(ConversationMessage, Option<TokenUsage>), RuntimeError> {
-    (
-        ConversationMessage,
-        Option<TokenUsage>,
-        Vec<PromptCacheEvent>,
-    ),
-    RuntimeError,
-> {
     let mut text = String::new();
     let mut blocks = Vec::new();
-    let mut prompt_cache_events = Vec::new();
     let mut finished = false;
     let mut usage = None;
 
@@ -327,7 +461,6 @@ fn build_assistant_message(
                 blocks.push(ContentBlock::ToolUse { id, name, input });
             }
             AssistantEvent::Usage(value) => usage = Some(value),
-            AssistantEvent::PromptCache(event) => prompt_cache_events.push(event),
             AssistantEvent::MessageStop => {
                 finished = true;
             }
@@ -348,7 +481,6 @@ fn build_assistant_message(
     Ok((
         ConversationMessage::assistant_with_usage(blocks, usage),
         usage,
-        prompt_cache_events,
     ))
 }
 
@@ -421,7 +553,7 @@ impl ToolExecutor for StaticToolExecutor {
 #[cfg(test)]
 mod tests {
     use super::{
-        ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, PromptCacheEvent, RuntimeError,
+        ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError,
         StaticToolExecutor,
     };
     use crate::compact::CompactionConfig;
@@ -434,6 +566,8 @@ mod tests {
     use crate::session::{ContentBlock, MessageRole, Session};
     use crate::usage::TokenUsage;
     use std::path::PathBuf;
+    use std::sync::Arc;
+    use telemetry::{MemoryTelemetrySink, SessionTracer, TelemetryEvent};
 
     struct ScriptedApiClient {
         call_count: usize,
@@ -478,15 +612,6 @@ mod tests {
                             cache_creation_input_tokens: 1,
                             cache_read_input_tokens: 3,
                         }),
-                        AssistantEvent::PromptCache(PromptCacheEvent {
-                            unexpected: true,
-                            reason:
-                                "cache read tokens dropped while prompt fingerprint remained stable"
-                                    .to_string(),
-                            previous_cache_read_input_tokens: 6_000,
-                            current_cache_read_input_tokens: 1_000,
-                            token_drop: 5_000,
-                        }),
                         AssistantEvent::MessageStop,
                     ])
                 }
@@ -540,10 +665,8 @@ mod tests {
         assert_eq!(summary.iterations, 2);
         assert_eq!(summary.assistant_messages.len(), 2);
         assert_eq!(summary.tool_results.len(), 1);
-        assert_eq!(summary.prompt_cache_events.len(), 1);
         assert_eq!(runtime.session().messages.len(), 4);
         assert_eq!(summary.usage.output_tokens, 10);
-        assert!(summary.prompt_cache_events[0].unexpected);
         assert!(matches!(
             runtime.session().messages[1].blocks[1],
             ContentBlock::ToolUse { .. }
@@ -557,6 +680,39 @@ mod tests {
         ));
     }
 
+    #[test]
+    fn records_runtime_session_trace_events() {
+        let sink = Arc::new(MemoryTelemetrySink::default());
+        let tracer = SessionTracer::new("session-runtime", sink.clone());
+        let mut runtime = ConversationRuntime::new(
+            Session::new(),
+            ScriptedApiClient { call_count: 0 },
+            StaticToolExecutor::new().register("add", |_input| Ok("4".to_string())),
+            PermissionPolicy::new(PermissionMode::WorkspaceWrite),
+            vec!["system".to_string()],
+        )
+        .with_session_tracer(tracer);
+
+        runtime
+            .run_turn("what is 2 + 2?", Some(&mut PromptAllowOnce))
+            .expect("conversation loop should succeed");
+
+        let events = sink.events();
+        let trace_names = events
+            .iter()
+            .filter_map(|event| match event {
+                TelemetryEvent::SessionTrace(trace) => Some(trace.name.as_str()),
+                _ => None,
+            })
+            .collect::<Vec<_>>();
+
+        assert!(trace_names.contains(&"turn_started"));
+        assert!(trace_names.contains(&"assistant_iteration_completed"));
+        assert!(trace_names.contains(&"tool_execution_started"));
+        assert!(trace_names.contains(&"tool_execution_finished"));
+        assert!(trace_names.contains(&"turn_completed"));
+    }
+
     #[test]
     fn records_denied_tool_results_when_prompt_rejects() {
         struct RejectPrompter;

rust/crates/runtime/src/hooks.rs

@@ -113,19 +113,19 @@ impl HookRunner {
             "tool_result_is_error": is_error,
         })
         .to_string();
-
+        let invocation = HookInvocation {
-        let mut messages = Vec::new();
-
-        for command in commands {
-            match Self::run_command(
-                command,
             event,
             tool_name,
             tool_input,
             tool_output,
             is_error,
-                &payload,
+            payload: &payload,
-            ) {
+        };
+
+        let mut messages = Vec::new();
+
+        for command in commands {
+            match Self::run_command(command, &invocation) {
                 HookCommandOutcome::Allow { message } => {
                     if let Some(message) = message {
                         messages.push(message);
@@ -148,28 +148,23 @@ impl HookRunner {
         HookRunResult::allow(messages)
     }
 
-    fn run_command(
+    fn run_command(command: &str, invocation: &HookInvocation<'_>) -> HookCommandOutcome {
-        command: &str,
-        event: HookEvent,
-        tool_name: &str,
-        tool_input: &str,
-        tool_output: Option<&str>,
-        is_error: bool,
-        payload: &str,
-    ) -> HookCommandOutcome {
         let mut child = shell_command(command);
         child.stdin(std::process::Stdio::piped());
         child.stdout(std::process::Stdio::piped());
         child.stderr(std::process::Stdio::piped());
-        child.env("HOOK_EVENT", event.as_str());
+        child.env("HOOK_EVENT", invocation.event.as_str());
-        child.env("HOOK_TOOL_NAME", tool_name);
+        child.env("HOOK_TOOL_NAME", invocation.tool_name);
-        child.env("HOOK_TOOL_INPUT", tool_input);
+        child.env("HOOK_TOOL_INPUT", invocation.tool_input);
-        child.env("HOOK_TOOL_IS_ERROR", if is_error { "1" } else { "0" });
+        child.env(
-        if let Some(tool_output) = tool_output {
+            "HOOK_TOOL_IS_ERROR",
+            if invocation.is_error { "1" } else { "0" },
+        );
+        if let Some(tool_output) = invocation.tool_output {
             child.env("HOOK_TOOL_OUTPUT", tool_output);
         }
 
-        match child.output_with_stdin(payload.as_bytes()) {
+        match child.output_with_stdin(invocation.payload.as_bytes()) {
             Ok(output) => {
                 let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
                 let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
@@ -187,8 +182,9 @@ impl HookRunner {
                     },
                     None => HookCommandOutcome::Warn {
                         message: format!(
-                            "{} hook `{command}` terminated by signal while handling `{tool_name}`",
+                            "{} hook `{command}` terminated by signal while handling `{}`",
-                            event.as_str()
+                            invocation.event.as_str(),
+                            invocation.tool_name
                         ),
                     },
                 }
@@ -196,13 +192,23 @@ impl HookRunner {
             Err(error) => HookCommandOutcome::Warn {
                 message: format!(
                     "{} hook `{command}` failed to start for `{tool_name}`: {error}",
-                    event.as_str()
+                    invocation.event.as_str(),
+                    tool_name = invocation.tool_name
                 ),
             },
         }
     }
 }
 
+struct HookInvocation<'a> {
+    event: HookEvent,
+    tool_name: &'a str,
+    tool_input: &'a str,
+    tool_output: Option<&'a str>,
+    is_error: bool,
+    payload: &'a str,
+}
+
 enum HookCommandOutcome {
     Allow { message: Option<String> },
     Deny { message: Option<String> },

rust/crates/runtime/src/lib.rs

@@ -31,8 +31,8 @@ pub use config::{
     ScopedMcpServerConfig, CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
 };
 pub use conversation::{
-    ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, PromptCacheEvent, RuntimeError,
+    ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError, StaticToolExecutor,
-    StaticToolExecutor, ToolError, ToolExecutor, TurnSummary,
+    ToolError, ToolExecutor, TurnSummary,
 };
 pub use file_ops::{
     edit_file, glob_search, grep_search, read_file, write_file, EditFileOutput, GlobSearchOutput,

rust/crates/runtime/src/mcp_stdio.rs

@@ -1144,8 +1144,20 @@ mod tests {
     }
 
     fn cleanup_script(script_path: &Path) {
-        fs::remove_file(script_path).expect("cleanup script");
+        if let Err(error) = fs::remove_file(script_path) {
-        fs::remove_dir_all(script_path.parent().expect("script parent")).expect("cleanup dir");
+            assert_eq!(
+                error.kind(),
+                std::io::ErrorKind::NotFound,
+                "cleanup script: {error}"
+            );
+        }
+        if let Err(error) = fs::remove_dir_all(script_path.parent().expect("script parent")) {
+            assert_eq!(
+                error.kind(),
+                std::io::ErrorKind::NotFound,
+                "cleanup dir: {error}"
+            );
+        }
     }
 
     fn manager_server_config(

rust/crates/rusty-claude-cli/src/main.rs

@@ -4,6 +4,7 @@ mod render;
 
 use std::collections::{BTreeMap, BTreeSet};
 use std::env;
+use std::fmt::Write as _;
 use std::fs;
 use std::io::{self, Read, Write};
 use std::net::TcpListener;
@@ -13,8 +14,8 @@ use std::time::{SystemTime, UNIX_EPOCH};
 
 use api::{
     resolve_startup_auth_source, AnthropicClient, AuthSource, ContentBlockDelta, InputContentBlock,
-    InputMessage, MessageRequest, MessageResponse, OutputContentBlock, PromptCache,
+    InputMessage, JsonlTelemetrySink, MessageRequest, MessageResponse, OutputContentBlock,
-    PromptCacheRecord, StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition,
+    SessionTracer, StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition,
     ToolResultContentBlock,
 };
 
@@ -29,8 +30,8 @@ use runtime::{
     parse_oauth_callback_request_target, save_oauth_credentials, ApiClient, ApiRequest,
     AssistantEvent, CompactionConfig, ConfigLoader, ConfigSource, ContentBlock,
     ConversationMessage, ConversationRuntime, MessageRole, OAuthAuthorizationRequest, OAuthConfig,
-    OAuthTokenExchangeRequest, PermissionMode, PermissionPolicy, ProjectContext, PromptCacheEvent,
+    OAuthTokenExchangeRequest, PermissionMode, PermissionPolicy, ProjectContext, RuntimeError,
-    RuntimeError, Session, TokenUsage, ToolError, ToolExecutor, UsageTracker,
+    Session, TokenUsage, ToolError, ToolExecutor, UsageTracker,
 };
 use serde_json::json;
 use tools::{execute_tool, mvp_tool_specs, ToolSpec};
@@ -45,6 +46,7 @@ fn max_tokens_for_model(model: &str) -> u32 {
 }
 const DEFAULT_DATE: &str = "2026-03-31";
 const DEFAULT_OAUTH_CALLBACK_PORT: u16 = 4545;
+const TELEMETRY_LOG_PATH_ENV: &str = "CLAW_TELEMETRY_LOG_PATH";
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 const BUILD_TARGET: Option<&str> = option_env!("TARGET");
 const GIT_SHA: Option<&str> = option_env!("GIT_SHA");
@@ -996,7 +998,7 @@ impl LiveCli {
         let session = create_managed_session_handle()?;
         let runtime = build_runtime(
             Session::new(),
-            session.id.clone(),
+            &session.id,
             model.clone(),
             system_prompt.clone(),
             enable_tools,
@@ -1052,14 +1054,13 @@ impl LiveCli {
         let mut permission_prompter = CliPermissionPrompter::new(self.permission_mode);
         let result = self.runtime.run_turn(input, Some(&mut permission_prompter));
         match result {
-            Ok(summary) => {
+            Ok(_) => {
                 spinner.finish(
                     "✨ Done",
                     TerminalRenderer::new().color_theme(),
                     &mut stdout,
                 )?;
                 println!();
-                print_prompt_cache_events(&summary);
                 self.persist_session()?;
                 Ok(())
             }
@@ -1089,7 +1090,7 @@ impl LiveCli {
         let session = self.runtime.session().clone();
         let mut runtime = build_runtime(
             session,
-            self.session.id.clone(),
+            &self.session.id,
             self.model.clone(),
             self.system_prompt.clone(),
             true,
@@ -1109,7 +1110,6 @@ impl LiveCli {
                 "iterations": summary.iterations,
                 "tool_uses": collect_tool_uses(&summary),
                 "tool_results": collect_tool_results(&summary),
-                "prompt_cache_events": collect_prompt_cache_events(&summary),
                 "usage": {
                     "input_tokens": summary.usage.input_tokens,
                     "output_tokens": summary.usage.output_tokens,
@@ -1237,7 +1237,7 @@ impl LiveCli {
         let message_count = session.messages.len();
         self.runtime = build_runtime(
             session,
-            self.session.id.clone(),
+            &self.session.id,
             model.clone(),
             self.system_prompt.clone(),
             true,
@@ -1281,7 +1281,7 @@ impl LiveCli {
         self.permission_mode = permission_mode_from_label(normalized);
         self.runtime = build_runtime(
             session,
-            self.session.id.clone(),
+            &self.session.id,
             self.model.clone(),
             self.system_prompt.clone(),
             true,
@@ -1307,7 +1307,7 @@ impl LiveCli {
         self.session = create_managed_session_handle()?;
         self.runtime = build_runtime(
             Session::new(),
-            self.session.id.clone(),
+            &self.session.id,
             self.model.clone(),
             self.system_prompt.clone(),
             true,
@@ -1343,7 +1343,7 @@ impl LiveCli {
         let message_count = session.messages.len();
         self.runtime = build_runtime(
             session,
-            handle.id.clone(),
+            &handle.id,
             self.model.clone(),
             self.system_prompt.clone(),
             true,
@@ -1416,7 +1416,7 @@ impl LiveCli {
                 let message_count = session.messages.len();
                 self.runtime = build_runtime(
                     session,
-                    handle.id.clone(),
+                    &handle.id,
                     self.model.clone(),
                     self.system_prompt.clone(),
                     true,
@@ -1447,7 +1447,7 @@ impl LiveCli {
         let skipped = removed == 0;
         self.runtime = build_runtime(
             result.compacted_session,
-            self.session.id.clone(),
+            &self.session.id,
             self.model.clone(),
             self.system_prompt.clone(),
             true,
@@ -1926,7 +1926,7 @@ fn build_runtime_feature_config(
 #[allow(clippy::too_many_arguments)]
 fn build_runtime(
     session: Session,
-    session_id: String,
+    session_id: &str,
     model: String,
     system_prompt: Vec<String>,
     enable_tools: bool,
@@ -1935,20 +1935,41 @@ fn build_runtime(
     permission_mode: PermissionMode,
 ) -> Result<ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>, Box<dyn std::error::Error>>
 {
-    Ok(ConversationRuntime::new_with_features(
+    let session_tracer = build_session_tracer(session_id)?;
+    let api_client = match session_tracer.clone() {
+        Some(session_tracer) => {
+            AnthropicRuntimeClient::new(model, enable_tools, emit_output, allowed_tools.clone())?
+                .with_session_tracer(session_tracer)
+        }
+        None => {
+            AnthropicRuntimeClient::new(model, enable_tools, emit_output, allowed_tools.clone())?
+        }
+    };
+    let runtime = ConversationRuntime::new_with_features(
         session,
-        AnthropicRuntimeClient::new(
+        api_client,
-            model,
-            enable_tools,
-            emit_output,
-            allowed_tools.clone(),
-            session_id,
-        )?,
         CliToolExecutor::new(allowed_tools, emit_output),
         permission_policy(permission_mode),
         system_prompt,
         &build_runtime_feature_config()?,
-    ))
+    );
+    Ok(match session_tracer {
+        Some(session_tracer) => runtime.with_session_tracer(session_tracer),
+        None => runtime,
+    })
+}
+
+fn build_session_tracer(
+    session_id: &str,
+) -> Result<Option<SessionTracer>, Box<dyn std::error::Error>> {
+    let Some(path) = env::var_os(TELEMETRY_LOG_PATH_ENV) else {
+        return Ok(None);
+    };
+    let sink = JsonlTelemetrySink::new(PathBuf::from(path))?;
+    Ok(Some(SessionTracer::new(
+        session_id.to_string(),
+        std::sync::Arc::new(sink),
+    )))
 }
 
 struct CliPermissionPrompter {
@@ -2012,19 +2033,22 @@ impl AnthropicRuntimeClient {
         enable_tools: bool,
         emit_output: bool,
         allowed_tools: Option<AllowedToolSet>,
-        session_id: impl Into<String>,
     ) -> Result<Self, Box<dyn std::error::Error>> {
         Ok(Self {
             runtime: tokio::runtime::Runtime::new()?,
             client: AnthropicClient::from_auth(resolve_cli_auth_source()?)
-                .with_base_url(api::read_base_url())
+                .with_base_url(api::read_base_url()),
-                .with_prompt_cache(PromptCache::new(session_id)),
             model,
             enable_tools,
             emit_output,
             allowed_tools,
         })
     }
+
+    fn with_session_tracer(mut self, session_tracer: SessionTracer) -> Self {
+        self.client = self.client.with_session_tracer(session_tracer);
+        self
+    }
 }
 
 fn resolve_cli_auth_source() -> Result<AuthSource, Box<dyn std::error::Error>> {
@@ -2130,12 +2154,7 @@ impl ApiClient for AnthropicRuntimeClient {
                         }
                     }
                     ApiStreamEvent::MessageDelta(delta) => {
-                        events.push(AssistantEvent::Usage(TokenUsage {
+                        events.push(AssistantEvent::Usage(delta.usage.token_usage()));
-                            input_tokens: delta.usage.input_tokens,
-                            output_tokens: delta.usage.output_tokens,
-                            cache_creation_input_tokens: delta.usage.cache_creation_input_tokens,
-                            cache_read_input_tokens: delta.usage.cache_read_input_tokens,
-                        }));
                     }
                     ApiStreamEvent::MessageStop(_) => {
                         saw_stop = true;
@@ -2149,8 +2168,6 @@ impl ApiClient for AnthropicRuntimeClient {
                 }
             }
 
-            push_prompt_cache_record(&self.client, &mut events);
-
             if !saw_stop
                 && events.iter().any(|event| {
                     matches!(event, AssistantEvent::TextDelta(text) if !text.is_empty())
@@ -2175,9 +2192,7 @@ impl ApiClient for AnthropicRuntimeClient {
                 })
                 .await
                 .map_err(|error| RuntimeError::new(error.to_string()))?;
-            let mut events = response_to_events(response, out)?;
+            response_to_events(response, out)
-            push_prompt_cache_record(&self.client, &mut events);
-            Ok(events)
         })
     }
 }
@@ -2238,39 +2253,6 @@ fn collect_tool_results(summary: &runtime::TurnSummary) -> Vec<serde_json::Value
         .collect()
 }
 
-fn collect_prompt_cache_events(summary: &runtime::TurnSummary) -> Vec<serde_json::Value> {
-    summary
-        .prompt_cache_events
-        .iter()
-        .map(|event| {
-            json!({
-                "unexpected": event.unexpected,
-                "reason": event.reason,
-                "previous_cache_read_input_tokens": event.previous_cache_read_input_tokens,
-                "current_cache_read_input_tokens": event.current_cache_read_input_tokens,
-                "token_drop": event.token_drop,
-            })
-        })
-        .collect()
-}
-
-fn print_prompt_cache_events(summary: &runtime::TurnSummary) {
-    for event in &summary.prompt_cache_events {
-        let label = if event.unexpected {
-            "Prompt cache break"
-        } else {
-            "Prompt cache invalidation"
-        };
-        println!(
-            "{label}: {} (cache read {} -> {}, drop {})",
-            event.reason,
-            event.previous_cache_read_input_tokens,
-            event.current_cache_read_input_tokens,
-            event.token_drop,
-        );
-    }
-}
-
 fn slash_command_completion_candidates() -> Vec<String> {
     slash_command_specs()
         .iter()
@@ -2417,20 +2399,18 @@ fn first_visible_line(text: &str) -> &str {
 }
 
 fn format_bash_result(icon: &str, parsed: &serde_json::Value) -> String {
-    use std::fmt::Write as _;
-
     let mut lines = vec![format!("{icon} \x1b[38;5;245mbash\x1b[0m")];
     if let Some(task_id) = parsed
         .get("backgroundTaskId")
         .and_then(|value| value.as_str())
     {
-        let _ = write!(lines[0], " backgrounded ({task_id})");
+        write!(&mut lines[0], " backgrounded ({task_id})").expect("write to string");
     } else if let Some(status) = parsed
         .get("returnCodeInterpretation")
         .and_then(|value| value.as_str())
         .filter(|status| !status.is_empty())
     {
-        let _ = write!(lines[0], " {status}");
+        write!(&mut lines[0], " {status}").expect("write to string");
     }
 
     if let Some(stdout) = parsed.get("stdout").and_then(|value| value.as_str()) {
@@ -2670,36 +2650,11 @@ fn response_to_events(
         }
     }
 
-    events.push(AssistantEvent::Usage(TokenUsage {
+    events.push(AssistantEvent::Usage(response.usage.token_usage()));
-        input_tokens: response.usage.input_tokens,
-        output_tokens: response.usage.output_tokens,
-        cache_creation_input_tokens: response.usage.cache_creation_input_tokens,
-        cache_read_input_tokens: response.usage.cache_read_input_tokens,
-    }));
     events.push(AssistantEvent::MessageStop);
     Ok(events)
 }
 
-fn push_prompt_cache_record(client: &AnthropicClient, events: &mut Vec<AssistantEvent>) {
-    if let Some(event) = client
-        .take_last_prompt_cache_record()
-        .and_then(prompt_cache_record_to_runtime_event)
-    {
-        events.push(AssistantEvent::PromptCache(event));
-    }
-}
-
-fn prompt_cache_record_to_runtime_event(record: PromptCacheRecord) -> Option<PromptCacheEvent> {
-    let cache_break = record.cache_break?;
-    Some(PromptCacheEvent {
-        unexpected: cache_break.unexpected,
-        reason: cache_break.reason,
-        previous_cache_read_input_tokens: cache_break.previous_cache_read_input_tokens,
-        current_cache_read_input_tokens: cache_break.current_cache_read_input_tokens,
-        token_drop: cache_break.token_drop,
-    })
-}
-
 struct CliToolExecutor {
     renderer: TerminalRenderer,
     emit_output: bool,

rust/crates/telemetry/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "telemetry"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+publish.workspace = true
+
+[dependencies]
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+
+[lints]
+workspace = true

rust/crates/telemetry/src/lib.rs

@@ -0,0 +1,526 @@
+use std::fmt::{Debug, Formatter};
+use std::fs::{File, OpenOptions};
+use std::io::Write;
+use std::path::{Path, PathBuf};
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::{Arc, Mutex};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::{Deserialize, Serialize};
+use serde_json::{Map, Value};
+
+pub const DEFAULT_ANTHROPIC_VERSION: &str = "2023-06-01";
+pub const DEFAULT_APP_NAME: &str = "claude-code";
+pub const DEFAULT_RUNTIME: &str = "rust";
+pub const DEFAULT_AGENTIC_BETA: &str = "claude-code-20250219";
+pub const DEFAULT_PROMPT_CACHING_SCOPE_BETA: &str = "prompt-caching-scope-2026-01-05";
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ClientIdentity {
+    pub app_name: String,
+    pub app_version: String,
+    pub runtime: String,
+}
+
+impl ClientIdentity {
+    #[must_use]
+    pub fn new(app_name: impl Into<String>, app_version: impl Into<String>) -> Self {
+        Self {
+            app_name: app_name.into(),
+            app_version: app_version.into(),
+            runtime: DEFAULT_RUNTIME.to_string(),
+        }
+    }
+
+    #[must_use]
+    pub fn with_runtime(mut self, runtime: impl Into<String>) -> Self {
+        self.runtime = runtime.into();
+        self
+    }
+
+    #[must_use]
+    pub fn user_agent(&self) -> String {
+        format!("{}/{}", self.app_name, self.app_version)
+    }
+}
+
+impl Default for ClientIdentity {
+    fn default() -> Self {
+        Self::new(DEFAULT_APP_NAME, env!("CARGO_PKG_VERSION"))
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct AnthropicRequestProfile {
+    pub anthropic_version: String,
+    pub client_identity: ClientIdentity,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub betas: Vec<String>,
+    #[serde(default, skip_serializing_if = "Map::is_empty")]
+    pub extra_body: Map<String, Value>,
+}
+
+impl AnthropicRequestProfile {
+    #[must_use]
+    pub fn new(client_identity: ClientIdentity) -> Self {
+        Self {
+            anthropic_version: DEFAULT_ANTHROPIC_VERSION.to_string(),
+            client_identity,
+            betas: vec![
+                DEFAULT_AGENTIC_BETA.to_string(),
+                DEFAULT_PROMPT_CACHING_SCOPE_BETA.to_string(),
+            ],
+            extra_body: Map::new(),
+        }
+    }
+
+    #[must_use]
+    pub fn with_beta(mut self, beta: impl Into<String>) -> Self {
+        let beta = beta.into();
+        if !self.betas.contains(&beta) {
+            self.betas.push(beta);
+        }
+        self
+    }
+
+    #[must_use]
+    pub fn with_extra_body(mut self, key: impl Into<String>, value: Value) -> Self {
+        self.extra_body.insert(key.into(), value);
+        self
+    }
+
+    #[must_use]
+    pub fn header_pairs(&self) -> Vec<(String, String)> {
+        let mut headers = vec![
+            (
+                "anthropic-version".to_string(),
+                self.anthropic_version.clone(),
+            ),
+            ("user-agent".to_string(), self.client_identity.user_agent()),
+        ];
+        if !self.betas.is_empty() {
+            headers.push(("anthropic-beta".to_string(), self.betas.join(",")));
+        }
+        headers
+    }
+
+    pub fn render_json_body<T: Serialize>(&self, request: &T) -> Result<Value, serde_json::Error> {
+        let mut body = serde_json::to_value(request)?;
+        let object = body.as_object_mut().ok_or_else(|| {
+            serde_json::Error::io(std::io::Error::new(
+                std::io::ErrorKind::InvalidData,
+                "request body must serialize to a JSON object",
+            ))
+        })?;
+        for (key, value) in &self.extra_body {
+            object.insert(key.clone(), value.clone());
+        }
+        if !self.betas.is_empty() {
+            object.insert(
+                "betas".to_string(),
+                Value::Array(self.betas.iter().cloned().map(Value::String).collect()),
+            );
+        }
+        Ok(body)
+    }
+}
+
+impl Default for AnthropicRequestProfile {
+    fn default() -> Self {
+        Self::new(ClientIdentity::default())
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct AnalyticsEvent {
+    pub namespace: String,
+    pub action: String,
+    #[serde(default, skip_serializing_if = "Map::is_empty")]
+    pub properties: Map<String, Value>,
+}
+
+impl AnalyticsEvent {
+    #[must_use]
+    pub fn new(namespace: impl Into<String>, action: impl Into<String>) -> Self {
+        Self {
+            namespace: namespace.into(),
+            action: action.into(),
+            properties: Map::new(),
+        }
+    }
+
+    #[must_use]
+    pub fn with_property(mut self, key: impl Into<String>, value: Value) -> Self {
+        self.properties.insert(key.into(), value);
+        self
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct SessionTraceRecord {
+    pub session_id: String,
+    pub sequence: u64,
+    pub name: String,
+    pub timestamp_ms: u64,
+    #[serde(default, skip_serializing_if = "Map::is_empty")]
+    pub attributes: Map<String, Value>,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum TelemetryEvent {
+    HttpRequestStarted {
+        session_id: String,
+        attempt: u32,
+        method: String,
+        path: String,
+        #[serde(default, skip_serializing_if = "Map::is_empty")]
+        attributes: Map<String, Value>,
+    },
+    HttpRequestSucceeded {
+        session_id: String,
+        attempt: u32,
+        method: String,
+        path: String,
+        status: u16,
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        request_id: Option<String>,
+        #[serde(default, skip_serializing_if = "Map::is_empty")]
+        attributes: Map<String, Value>,
+    },
+    HttpRequestFailed {
+        session_id: String,
+        attempt: u32,
+        method: String,
+        path: String,
+        error: String,
+        retryable: bool,
+        #[serde(default, skip_serializing_if = "Map::is_empty")]
+        attributes: Map<String, Value>,
+    },
+    Analytics(AnalyticsEvent),
+    SessionTrace(SessionTraceRecord),
+}
+
+pub trait TelemetrySink: Send + Sync {
+    fn record(&self, event: TelemetryEvent);
+}
+
+#[derive(Default)]
+pub struct MemoryTelemetrySink {
+    events: Mutex<Vec<TelemetryEvent>>,
+}
+
+impl MemoryTelemetrySink {
+    #[must_use]
+    pub fn events(&self) -> Vec<TelemetryEvent> {
+        self.events
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .clone()
+    }
+}
+
+impl TelemetrySink for MemoryTelemetrySink {
+    fn record(&self, event: TelemetryEvent) {
+        self.events
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .push(event);
+    }
+}
+
+pub struct JsonlTelemetrySink {
+    path: PathBuf,
+    file: Mutex<File>,
+}
+
+impl Debug for JsonlTelemetrySink {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("JsonlTelemetrySink")
+            .field("path", &self.path)
+            .finish_non_exhaustive()
+    }
+}
+
+impl JsonlTelemetrySink {
+    pub fn new(path: impl AsRef<Path>) -> Result<Self, std::io::Error> {
+        let path = path.as_ref().to_path_buf();
+        if let Some(parent) = path.parent() {
+            std::fs::create_dir_all(parent)?;
+        }
+        let file = OpenOptions::new().create(true).append(true).open(&path)?;
+        Ok(Self {
+            path,
+            file: Mutex::new(file),
+        })
+    }
+
+    #[must_use]
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+impl TelemetrySink for JsonlTelemetrySink {
+    fn record(&self, event: TelemetryEvent) {
+        let Ok(line) = serde_json::to_string(&event) else {
+            return;
+        };
+        let mut file = self
+            .file
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let _ = writeln!(file, "{line}");
+        let _ = file.flush();
+    }
+}
+
+#[derive(Clone)]
+pub struct SessionTracer {
+    session_id: String,
+    sequence: Arc<AtomicU64>,
+    sink: Arc<dyn TelemetrySink>,
+}
+
+impl Debug for SessionTracer {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("SessionTracer")
+            .field("session_id", &self.session_id)
+            .finish_non_exhaustive()
+    }
+}
+
+impl SessionTracer {
+    #[must_use]
+    pub fn new(session_id: impl Into<String>, sink: Arc<dyn TelemetrySink>) -> Self {
+        Self {
+            session_id: session_id.into(),
+            sequence: Arc::new(AtomicU64::new(0)),
+            sink,
+        }
+    }
+
+    #[must_use]
+    pub fn session_id(&self) -> &str {
+        &self.session_id
+    }
+
+    pub fn record(&self, name: impl Into<String>, attributes: Map<String, Value>) {
+        let record = SessionTraceRecord {
+            session_id: self.session_id.clone(),
+            sequence: self.sequence.fetch_add(1, Ordering::Relaxed),
+            name: name.into(),
+            timestamp_ms: current_timestamp_ms(),
+            attributes,
+        };
+        self.sink.record(TelemetryEvent::SessionTrace(record));
+    }
+
+    pub fn record_http_request_started(
+        &self,
+        attempt: u32,
+        method: impl Into<String>,
+        path: impl Into<String>,
+        attributes: Map<String, Value>,
+    ) {
+        let method = method.into();
+        let path = path.into();
+        self.sink.record(TelemetryEvent::HttpRequestStarted {
+            session_id: self.session_id.clone(),
+            attempt,
+            method: method.clone(),
+            path: path.clone(),
+            attributes: attributes.clone(),
+        });
+        self.record(
+            "http_request_started",
+            merge_trace_fields(method, path, attempt, attributes),
+        );
+    }
+
+    pub fn record_http_request_succeeded(
+        &self,
+        attempt: u32,
+        method: impl Into<String>,
+        path: impl Into<String>,
+        status: u16,
+        request_id: Option<String>,
+        attributes: Map<String, Value>,
+    ) {
+        let method = method.into();
+        let path = path.into();
+        self.sink.record(TelemetryEvent::HttpRequestSucceeded {
+            session_id: self.session_id.clone(),
+            attempt,
+            method: method.clone(),
+            path: path.clone(),
+            status,
+            request_id: request_id.clone(),
+            attributes: attributes.clone(),
+        });
+        let mut trace_attributes = merge_trace_fields(method, path, attempt, attributes);
+        trace_attributes.insert("status".to_string(), Value::from(status));
+        if let Some(request_id) = request_id {
+            trace_attributes.insert("request_id".to_string(), Value::String(request_id));
+        }
+        self.record("http_request_succeeded", trace_attributes);
+    }
+
+    pub fn record_http_request_failed(
+        &self,
+        attempt: u32,
+        method: impl Into<String>,
+        path: impl Into<String>,
+        error: impl Into<String>,
+        retryable: bool,
+        attributes: Map<String, Value>,
+    ) {
+        let method = method.into();
+        let path = path.into();
+        let error = error.into();
+        self.sink.record(TelemetryEvent::HttpRequestFailed {
+            session_id: self.session_id.clone(),
+            attempt,
+            method: method.clone(),
+            path: path.clone(),
+            error: error.clone(),
+            retryable,
+            attributes: attributes.clone(),
+        });
+        let mut trace_attributes = merge_trace_fields(method, path, attempt, attributes);
+        trace_attributes.insert("error".to_string(), Value::String(error));
+        trace_attributes.insert("retryable".to_string(), Value::Bool(retryable));
+        self.record("http_request_failed", trace_attributes);
+    }
+
+    pub fn record_analytics(&self, event: AnalyticsEvent) {
+        let mut attributes = event.properties.clone();
+        attributes.insert(
+            "namespace".to_string(),
+            Value::String(event.namespace.clone()),
+        );
+        attributes.insert("action".to_string(), Value::String(event.action.clone()));
+        self.sink.record(TelemetryEvent::Analytics(event));
+        self.record("analytics", attributes);
+    }
+}
+
+fn merge_trace_fields(
+    method: String,
+    path: String,
+    attempt: u32,
+    mut attributes: Map<String, Value>,
+) -> Map<String, Value> {
+    attributes.insert("method".to_string(), Value::String(method));
+    attributes.insert("path".to_string(), Value::String(path));
+    attributes.insert("attempt".to_string(), Value::from(attempt));
+    attributes
+}
+
+fn current_timestamp_ms() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_millis()
+        .try_into()
+        .unwrap_or(u64::MAX)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn request_profile_emits_headers_and_merges_body() {
+        let profile = AnthropicRequestProfile::new(
+            ClientIdentity::new("claude-code", "1.2.3").with_runtime("rust-cli"),
+        )
+        .with_beta("tools-2026-04-01")
+        .with_extra_body("metadata", serde_json::json!({"source": "test"}));
+
+        assert_eq!(
+            profile.header_pairs(),
+            vec![
+                (
+                    "anthropic-version".to_string(),
+                    DEFAULT_ANTHROPIC_VERSION.to_string()
+                ),
+                ("user-agent".to_string(), "claude-code/1.2.3".to_string()),
+                (
+                    "anthropic-beta".to_string(),
+                    "claude-code-20250219,prompt-caching-scope-2026-01-05,tools-2026-04-01"
+                        .to_string(),
+                ),
+            ]
+        );
+
+        let body = profile
+            .render_json_body(&serde_json::json!({"model": "claude-sonnet"}))
+            .expect("body should serialize");
+        assert_eq!(
+            body["metadata"]["source"],
+            Value::String("test".to_string())
+        );
+        assert_eq!(
+            body["betas"],
+            serde_json::json!([
+                "claude-code-20250219",
+                "prompt-caching-scope-2026-01-05",
+                "tools-2026-04-01"
+            ])
+        );
+    }
+
+    #[test]
+    fn session_tracer_records_structured_events_and_trace_sequence() {
+        let sink = Arc::new(MemoryTelemetrySink::default());
+        let tracer = SessionTracer::new("session-123", sink.clone());
+
+        tracer.record_http_request_started(1, "POST", "/v1/messages", Map::new());
+        tracer.record_analytics(
+            AnalyticsEvent::new("cli", "prompt_sent")
+                .with_property("model", Value::String("claude-opus".to_string())),
+        );
+
+        let events = sink.events();
+        assert!(matches!(
+            &events[0],
+            TelemetryEvent::HttpRequestStarted {
+                session_id,
+                attempt: 1,
+                method,
+                path,
+                ..
+            } if session_id == "session-123" && method == "POST" && path == "/v1/messages"
+        ));
+        assert!(matches!(
+            &events[1],
+            TelemetryEvent::SessionTrace(SessionTraceRecord { sequence: 0, name, .. })
+            if name == "http_request_started"
+        ));
+        assert!(matches!(&events[2], TelemetryEvent::Analytics(_)));
+        assert!(matches!(
+            &events[3],
+            TelemetryEvent::SessionTrace(SessionTraceRecord { sequence: 1, name, .. })
+            if name == "analytics"
+        ));
+    }
+
+    #[test]
+    fn jsonl_sink_persists_events() {
+        let path =
+            std::env::temp_dir().join(format!("telemetry-jsonl-{}.log", current_timestamp_ms()));
+        let sink = JsonlTelemetrySink::new(&path).expect("sink should create file");
+
+        sink.record(TelemetryEvent::Analytics(
+            AnalyticsEvent::new("cli", "turn_completed").with_property("ok", Value::Bool(true)),
+        ));
+
+        let contents = std::fs::read_to_string(&path).expect("telemetry log should be readable");
+        assert!(contents.contains("\"type\":\"analytics\""));
+        assert!(contents.contains("\"action\":\"turn_completed\""));
+
+        let _ = std::fs::remove_file(path);
+    }
+}

rust/crates/tools/src/lib.rs

@@ -5,15 +5,15 @@ use std::time::{Duration, Instant};
 
 use api::{
     read_base_url, AnthropicClient, ContentBlockDelta, InputContentBlock, InputMessage,
-    MessageRequest, MessageResponse, OutputContentBlock, PromptCache, PromptCacheRecord,
+    MessageRequest, MessageResponse, OutputContentBlock, StreamEvent as ApiStreamEvent, ToolChoice,
-    StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition, ToolResultContentBlock,
+    ToolDefinition, ToolResultContentBlock,
 };
 use reqwest::blocking::Client;
 use runtime::{
     edit_file, execute_bash, glob_search, grep_search, load_system_prompt, read_file, write_file,
     ApiClient, ApiRequest, AssistantEvent, BashCommandInput, ContentBlock, ConversationMessage,
     ConversationRuntime, GrepSearchInput, MessageRole, PermissionMode, PermissionPolicy,
-    PromptCacheEvent, RuntimeError, Session, TokenUsage, ToolError, ToolExecutor,
+    RuntimeError, Session, ToolError, ToolExecutor,
 };
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
@@ -1466,8 +1466,7 @@ fn build_agent_runtime(
         .clone()
         .unwrap_or_else(|| DEFAULT_AGENT_MODEL.to_string());
     let allowed_tools = job.allowed_tools.clone();
-    let api_client =
+    let api_client = AnthropicRuntimeClient::new(model, allowed_tools.clone())?;
-        AnthropicRuntimeClient::new(model, allowed_tools.clone(), job.manifest.agent_id.clone())?;
     let tool_executor = SubagentToolExecutor::new(allowed_tools);
     Ok(ConversationRuntime::new(
         Session::new(),
@@ -1644,15 +1643,10 @@ struct AnthropicRuntimeClient {
 }
 
 impl AnthropicRuntimeClient {
-    fn new(
+    fn new(model: String, allowed_tools: BTreeSet<String>) -> Result<Self, String> {
-        model: String,
-        allowed_tools: BTreeSet<String>,
-        session_id: impl Into<String>,
-    ) -> Result<Self, String> {
         let client = AnthropicClient::from_env()
             .map_err(|error| error.to_string())?
-            .with_base_url(read_base_url())
+            .with_base_url(read_base_url());
-            .with_prompt_cache(PromptCache::new(session_id));
         Ok(Self {
             runtime: tokio::runtime::Runtime::new().map_err(|error| error.to_string())?,
             client,
@@ -1663,7 +1657,6 @@ impl AnthropicRuntimeClient {
 }
 
 impl ApiClient for AnthropicRuntimeClient {
-    #[allow(clippy::too_many_lines)]
     fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
         let tools = tool_specs_for_allowed_tools(Some(&self.allowed_tools))
             .into_iter()
@@ -1730,12 +1723,7 @@ impl ApiClient for AnthropicRuntimeClient {
                         }
                     }
                     ApiStreamEvent::MessageDelta(delta) => {
-                        events.push(AssistantEvent::Usage(TokenUsage {
+                        events.push(AssistantEvent::Usage(delta.usage.token_usage()));
-                            input_tokens: delta.usage.input_tokens,
-                            output_tokens: delta.usage.output_tokens,
-                            cache_creation_input_tokens: delta.usage.cache_creation_input_tokens,
-                            cache_read_input_tokens: delta.usage.cache_read_input_tokens,
-                        }));
                     }
                     ApiStreamEvent::MessageStop(_) => {
                         saw_stop = true;
@@ -1744,8 +1732,6 @@ impl ApiClient for AnthropicRuntimeClient {
                 }
             }
 
-            push_prompt_cache_record(&self.client, &mut events);
-
             if !saw_stop
                 && events.iter().any(|event| {
                     matches!(event, AssistantEvent::TextDelta(text) if !text.is_empty())
@@ -1770,9 +1756,7 @@ impl ApiClient for AnthropicRuntimeClient {
                 })
                 .await
                 .map_err(|error| RuntimeError::new(error.to_string()))?;
-            let mut events = response_to_events(response);
+            Ok(response_to_events(response))
-            push_prompt_cache_record(&self.client, &mut events);
-            Ok(events)
         })
     }
 }
@@ -1885,36 +1869,11 @@ fn response_to_events(response: MessageResponse) -> Vec<AssistantEvent> {
         }
     }
 
-    events.push(AssistantEvent::Usage(TokenUsage {
+    events.push(AssistantEvent::Usage(response.usage.token_usage()));
-        input_tokens: response.usage.input_tokens,
-        output_tokens: response.usage.output_tokens,
-        cache_creation_input_tokens: response.usage.cache_creation_input_tokens,
-        cache_read_input_tokens: response.usage.cache_read_input_tokens,
-    }));
     events.push(AssistantEvent::MessageStop);
     events
 }
 
-fn push_prompt_cache_record(client: &AnthropicClient, events: &mut Vec<AssistantEvent>) {
-    if let Some(event) = client
-        .take_last_prompt_cache_record()
-        .and_then(prompt_cache_record_to_runtime_event)
-    {
-        events.push(AssistantEvent::PromptCache(event));
-    }
-}
-
-fn prompt_cache_record_to_runtime_event(record: PromptCacheRecord) -> Option<PromptCacheEvent> {
-    let cache_break = record.cache_break?;
-    Some(PromptCacheEvent {
-        unexpected: cache_break.unexpected,
-        reason: cache_break.reason,
-        previous_cache_read_input_tokens: cache_break.previous_cache_read_input_tokens,
-        current_cache_read_input_tokens: cache_break.current_cache_read_input_tokens,
-        token_drop: cache_break.token_drop,
-    })
-}
-
 fn final_assistant_text(summary: &runtime::TurnSummary) -> String {
     summary
         .assistant_messages