diff --git a/rust/crates/runtime/src/lib.rs b/rust/crates/runtime/src/lib.rs
index 75c1b9f..b3a43d5 100644
--- a/rust/crates/runtime/src/lib.rs
+++ b/rust/crates/runtime/src/lib.rs
@@ -17,6 +17,7 @@ pub mod sandbox;
 mod session;
 mod sse;
 pub mod task_registry;
+pub mod team_cron_registry;
 mod usage;
 
 pub use bash::{execute_bash, BashCommandInput, BashCommandOutput};
diff --git a/rust/crates/runtime/src/team_cron_registry.rs b/rust/crates/runtime/src/team_cron_registry.rs
new file mode 100644
index 0000000..2fc14cc
--- /dev/null
+++ b/rust/crates/runtime/src/team_cron_registry.rs
@@ -0,0 +1,363 @@
+//! In-memory registries for Team and Cron lifecycle management.
+//!
+//! Provides TeamCreate/Delete and CronCreate/Delete/List runtime backing
+//! to replace the stub implementations in the tools crate.
+
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::{Deserialize, Serialize};
+
+fn now_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}
+
+// ─────────────────────────────────────────────
+// Team registry
+// ─────────────────────────────────────────────
+
+/// A team groups multiple tasks for parallel execution.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Team {
+    pub team_id: String,
+    pub name: String,
+    pub task_ids: Vec<String>,
+    pub status: TeamStatus,
+    pub created_at: u64,
+    pub updated_at: u64,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum TeamStatus {
+    Created,
+    Running,
+    Completed,
+    Deleted,
+}
+
+impl std::fmt::Display for TeamStatus {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Created => write!(f, "created"),
+            Self::Running => write!(f, "running"),
+            Self::Completed => write!(f, "completed"),
+            Self::Deleted => write!(f, "deleted"),
+        }
+    }
+}
+
+/// Thread-safe team registry.
+#[derive(Debug, Clone, Default)]
+pub struct TeamRegistry {
+    inner: Arc<Mutex<TeamInner>>,
+}
+
+#[derive(Debug, Default)]
+struct TeamInner {
+    teams: HashMap<String, Team>,
+    counter: u64,
+}
+
+impl TeamRegistry {
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Create a new team with the given name and task IDs.
+    pub fn create(&self, name: &str, task_ids: Vec<String>) -> Team {
+        let mut inner = self.inner.lock().expect("team registry lock poisoned");
+        inner.counter += 1;
+        let ts = now_secs();
+        let team_id = format!("team_{:08x}_{}", ts, inner.counter);
+        let team = Team {
+            team_id: team_id.clone(),
+            name: name.to_owned(),
+            task_ids,
+            status: TeamStatus::Created,
+            created_at: ts,
+            updated_at: ts,
+        };
+        inner.teams.insert(team_id, team.clone());
+        team
+    }
+
+    /// Get a team by ID.
+    pub fn get(&self, team_id: &str) -> Option<Team> {
+        let inner = self.inner.lock().expect("team registry lock poisoned");
+        inner.teams.get(team_id).cloned()
+    }
+
+    /// List all teams.
+    pub fn list(&self) -> Vec<Team> {
+        let inner = self.inner.lock().expect("team registry lock poisoned");
+        inner.teams.values().cloned().collect()
+    }
+
+    /// Delete a team.
+    pub fn delete(&self, team_id: &str) -> Result<Team, String> {
+        let mut inner = self.inner.lock().expect("team registry lock poisoned");
+        let team = inner
+            .teams
+            .get_mut(team_id)
+            .ok_or_else(|| format!("team not found: {team_id}"))?;
+        team.status = TeamStatus::Deleted;
+        team.updated_at = now_secs();
+        Ok(team.clone())
+    }
+
+    /// Remove a team entirely from the registry.
+    pub fn remove(&self, team_id: &str) -> Option<Team> {
+        let mut inner = self.inner.lock().expect("team registry lock poisoned");
+        inner.teams.remove(team_id)
+    }
+
+    #[must_use]
+    pub fn len(&self) -> usize {
+        let inner = self.inner.lock().expect("team registry lock poisoned");
+        inner.teams.len()
+    }
+
+    #[must_use]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+
+// ─────────────────────────────────────────────
+// Cron registry
+// ─────────────────────────────────────────────
+
+/// A cron entry schedules a prompt to run on a recurring schedule.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct CronEntry {
+    pub cron_id: String,
+    pub schedule: String,
+    pub prompt: String,
+    pub description: Option<String>,
+    pub enabled: bool,
+    pub created_at: u64,
+    pub updated_at: u64,
+    pub last_run_at: Option<u64>,
+    pub run_count: u64,
+}
+
+/// Thread-safe cron registry.
+#[derive(Debug, Clone, Default)]
+pub struct CronRegistry {
+    inner: Arc<Mutex<CronInner>>,
+}
+
+#[derive(Debug, Default)]
+struct CronInner {
+    entries: HashMap<String, CronEntry>,
+    counter: u64,
+}
+
+impl CronRegistry {
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Create a new cron entry.
+    pub fn create(&self, schedule: &str, prompt: &str, description: Option<&str>) -> CronEntry {
+        let mut inner = self.inner.lock().expect("cron registry lock poisoned");
+        inner.counter += 1;
+        let ts = now_secs();
+        let cron_id = format!("cron_{:08x}_{}", ts, inner.counter);
+        let entry = CronEntry {
+            cron_id: cron_id.clone(),
+            schedule: schedule.to_owned(),
+            prompt: prompt.to_owned(),
+            description: description.map(str::to_owned),
+            enabled: true,
+            created_at: ts,
+            updated_at: ts,
+            last_run_at: None,
+            run_count: 0,
+        };
+        inner.entries.insert(cron_id, entry.clone());
+        entry
+    }
+
+    /// Get a cron entry by ID.
+    pub fn get(&self, cron_id: &str) -> Option<CronEntry> {
+        let inner = self.inner.lock().expect("cron registry lock poisoned");
+        inner.entries.get(cron_id).cloned()
+    }
+
+    /// List all cron entries, optionally filtered to enabled only.
+    pub fn list(&self, enabled_only: bool) -> Vec<CronEntry> {
+        let inner = self.inner.lock().expect("cron registry lock poisoned");
+        inner
+            .entries
+            .values()
+            .filter(|e| !enabled_only || e.enabled)
+            .cloned()
+            .collect()
+    }
+
+    /// Delete (remove) a cron entry.
+    pub fn delete(&self, cron_id: &str) -> Result<CronEntry, String> {
+        let mut inner = self.inner.lock().expect("cron registry lock poisoned");
+        inner
+            .entries
+            .remove(cron_id)
+            .ok_or_else(|| format!("cron not found: {cron_id}"))
+    }
+
+    /// Disable a cron entry without removing it.
+    pub fn disable(&self, cron_id: &str) -> Result<(), String> {
+        let mut inner = self.inner.lock().expect("cron registry lock poisoned");
+        let entry = inner
+            .entries
+            .get_mut(cron_id)
+            .ok_or_else(|| format!("cron not found: {cron_id}"))?;
+        entry.enabled = false;
+        entry.updated_at = now_secs();
+        Ok(())
+    }
+
+    /// Record a cron run.
+    pub fn record_run(&self, cron_id: &str) -> Result<(), String> {
+        let mut inner = self.inner.lock().expect("cron registry lock poisoned");
+        let entry = inner
+            .entries
+            .get_mut(cron_id)
+            .ok_or_else(|| format!("cron not found: {cron_id}"))?;
+        entry.last_run_at = Some(now_secs());
+        entry.run_count += 1;
+        entry.updated_at = now_secs();
+        Ok(())
+    }
+
+    #[must_use]
+    pub fn len(&self) -> usize {
+        let inner = self.inner.lock().expect("cron registry lock poisoned");
+        inner.entries.len()
+    }
+
+    #[must_use]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // ── Team tests ──────────────────────────────────────
+
+    #[test]
+    fn creates_and_retrieves_team() {
+        let registry = TeamRegistry::new();
+        let team = registry.create("Alpha Squad", vec!["task_001".into(), "task_002".into()]);
+        assert_eq!(team.name, "Alpha Squad");
+        assert_eq!(team.task_ids.len(), 2);
+        assert_eq!(team.status, TeamStatus::Created);
+
+        let fetched = registry.get(&team.team_id).expect("team should exist");
+        assert_eq!(fetched.team_id, team.team_id);
+    }
+
+    #[test]
+    fn lists_and_deletes_teams() {
+        let registry = TeamRegistry::new();
+        let t1 = registry.create("Team A", vec![]);
+        let t2 = registry.create("Team B", vec![]);
+
+        let all = registry.list();
+        assert_eq!(all.len(), 2);
+
+        let deleted = registry.delete(&t1.team_id).expect("delete should succeed");
+        assert_eq!(deleted.status, TeamStatus::Deleted);
+
+        // Team is still listable (soft delete)
+        let still_there = registry.get(&t1.team_id).unwrap();
+        assert_eq!(still_there.status, TeamStatus::Deleted);
+
+        // Hard remove
+        registry.remove(&t2.team_id);
+        assert_eq!(registry.len(), 1);
+    }
+
+    #[test]
+    fn rejects_missing_team_operations() {
+        let registry = TeamRegistry::new();
+        assert!(registry.delete("nonexistent").is_err());
+        assert!(registry.get("nonexistent").is_none());
+    }
+
+    // ── Cron tests ──────────────────────────────────────
+
+    #[test]
+    fn creates_and_retrieves_cron() {
+        let registry = CronRegistry::new();
+        let entry = registry.create("0 * * * *", "Check status", Some("hourly check"));
+        assert_eq!(entry.schedule, "0 * * * *");
+        assert_eq!(entry.prompt, "Check status");
+        assert!(entry.enabled);
+        assert_eq!(entry.run_count, 0);
+        assert!(entry.last_run_at.is_none());
+
+        let fetched = registry.get(&entry.cron_id).expect("cron should exist");
+        assert_eq!(fetched.cron_id, entry.cron_id);
+    }
+
+    #[test]
+    fn lists_with_enabled_filter() {
+        let registry = CronRegistry::new();
+        let c1 = registry.create("* * * * *", "Task 1", None);
+        let c2 = registry.create("0 * * * *", "Task 2", None);
+        registry
+            .disable(&c1.cron_id)
+            .expect("disable should succeed");
+
+        let all = registry.list(false);
+        assert_eq!(all.len(), 2);
+
+        let enabled_only = registry.list(true);
+        assert_eq!(enabled_only.len(), 1);
+        assert_eq!(enabled_only[0].cron_id, c2.cron_id);
+    }
+
+    #[test]
+    fn deletes_cron_entry() {
+        let registry = CronRegistry::new();
+        let entry = registry.create("* * * * *", "To delete", None);
+        let deleted = registry
+            .delete(&entry.cron_id)
+            .expect("delete should succeed");
+        assert_eq!(deleted.cron_id, entry.cron_id);
+        assert!(registry.get(&entry.cron_id).is_none());
+        assert!(registry.is_empty());
+    }
+
+    #[test]
+    fn records_cron_runs() {
+        let registry = CronRegistry::new();
+        let entry = registry.create("*/5 * * * *", "Recurring", None);
+        registry.record_run(&entry.cron_id).unwrap();
+        registry.record_run(&entry.cron_id).unwrap();
+
+        let fetched = registry.get(&entry.cron_id).unwrap();
+        assert_eq!(fetched.run_count, 2);
+        assert!(fetched.last_run_at.is_some());
+    }
+
+    #[test]
+    fn rejects_missing_cron_operations() {
+        let registry = CronRegistry::new();
+        assert!(registry.delete("nonexistent").is_err());
+        assert!(registry.disable("nonexistent").is_err());
+        assert!(registry.record_run("nonexistent").is_err());
+        assert!(registry.get("nonexistent").is_none());
+    }
+}
diff --git a/rust/crates/tools/src/lib.rs b/rust/crates/tools/src/lib.rs
index a9f65ad..34f32fd 100644
--- a/rust/crates/tools/src/lib.rs
+++ b/rust/crates/tools/src/lib.rs
@@ -12,15 +12,28 @@ use plugins::PluginTool;
 use reqwest::blocking::Client;
 use runtime::{
     edit_file, execute_bash, glob_search, grep_search, load_system_prompt, read_file,
-    task_registry::TaskRegistry, write_file, ApiClient, ApiRequest, AssistantEvent,
-    BashCommandInput, ContentBlock, ConversationMessage, ConversationRuntime, GrepSearchInput,
-    MessageRole, PermissionMode, PermissionPolicy, PromptCacheEvent, RuntimeError, Session,
-    ToolError, ToolExecutor,
+    task_registry::TaskRegistry,
+    team_cron_registry::{CronRegistry, TeamRegistry},
+    write_file, ApiClient, ApiRequest, AssistantEvent, BashCommandInput, ContentBlock,
+    ConversationMessage, ConversationRuntime, GrepSearchInput, MessageRole, PermissionMode,
+    PermissionPolicy, PromptCacheEvent, RuntimeError, Session, ToolError, ToolExecutor,
 };
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
 
 /// Global task registry shared across tool invocations within a session.
+fn global_team_registry() -> &'static TeamRegistry {
+    use std::sync::OnceLock;
+    static REGISTRY: OnceLock<TeamRegistry> = OnceLock::new();
+    REGISTRY.get_or_init(TeamRegistry::new)
+}
+
+fn global_cron_registry() -> &'static CronRegistry {
+    use std::sync::OnceLock;
+    static REGISTRY: OnceLock<CronRegistry> = OnceLock::new();
+    REGISTRY.get_or_init(CronRegistry::new)
+}
+
 fn global_task_registry() -> &'static TaskRegistry {
     use std::sync::OnceLock;
     static REGISTRY: OnceLock<TaskRegistry> = OnceLock::new();
@@ -1007,59 +1020,86 @@ fn run_task_output(input: TaskIdInput) -> Result<String, String> {
 
 #[allow(clippy::needless_pass_by_value)]
 fn run_team_create(input: TeamCreateInput) -> Result<String, String> {
-    let team_id = format!(
-        "team_{:08x}",
-        std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs()
-    );
+    let task_ids: Vec<String> = input
+        .tasks
+        .iter()
+        .filter_map(|t| t.get("task_id").and_then(|v| v.as_str()).map(str::to_owned))
+        .collect();
+    let team = global_team_registry().create(&input.name, task_ids);
+    // Register team assignment on each task
+    for task_id in &team.task_ids {
+        let _ = global_task_registry().assign_team(task_id, &team.team_id);
+    }
     to_pretty_json(json!({
-        "team_id": team_id,
-        "name": input.name,
-        "task_count": input.tasks.len(),
-        "status": "created"
+        "team_id": team.team_id,
+        "name": team.name,
+        "task_count": team.task_ids.len(),
+        "task_ids": team.task_ids,
+        "status": team.status,
+        "created_at": team.created_at
     }))
 }
 
 #[allow(clippy::needless_pass_by_value)]
 fn run_team_delete(input: TeamDeleteInput) -> Result<String, String> {
-    to_pretty_json(json!({
-        "team_id": input.team_id,
-        "status": "deleted"
-    }))
+    match global_team_registry().delete(&input.team_id) {
+        Ok(team) => to_pretty_json(json!({
+            "team_id": team.team_id,
+            "name": team.name,
+            "status": team.status,
+            "message": "Team deleted"
+        })),
+        Err(e) => Err(e),
+    }
 }
 
 #[allow(clippy::needless_pass_by_value)]
 fn run_cron_create(input: CronCreateInput) -> Result<String, String> {
-    let cron_id = format!(
-        "cron_{:08x}",
-        std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs()
-    );
+    let entry =
+        global_cron_registry().create(&input.schedule, &input.prompt, input.description.as_deref());
     to_pretty_json(json!({
-        "cron_id": cron_id,
-        "schedule": input.schedule,
-        "prompt": input.prompt,
-        "description": input.description,
-        "status": "created"
+        "cron_id": entry.cron_id,
+        "schedule": entry.schedule,
+        "prompt": entry.prompt,
+        "description": entry.description,
+        "enabled": entry.enabled,
+        "created_at": entry.created_at
     }))
 }
 
 #[allow(clippy::needless_pass_by_value)]
 fn run_cron_delete(input: CronDeleteInput) -> Result<String, String> {
-    to_pretty_json(json!({
-        "cron_id": input.cron_id,
-        "status": "deleted"
-    }))
+    match global_cron_registry().delete(&input.cron_id) {
+        Ok(entry) => to_pretty_json(json!({
+            "cron_id": entry.cron_id,
+            "schedule": entry.schedule,
+            "status": "deleted",
+            "message": "Cron entry removed"
+        })),
+        Err(e) => Err(e),
+    }
 }
 
 fn run_cron_list(_input: Value) -> Result<String, String> {
+    let entries: Vec<_> = global_cron_registry()
+        .list(false)
+        .into_iter()
+        .map(|e| {
+            json!({
+                "cron_id": e.cron_id,
+                "schedule": e.schedule,
+                "prompt": e.prompt,
+                "description": e.description,
+                "enabled": e.enabled,
+                "run_count": e.run_count,
+                "last_run_at": e.last_run_at,
+                "created_at": e.created_at
+            })
+        })
+        .collect();
     to_pretty_json(json!({
-        "crons": [],
-        "message": "No scheduled tasks found"
+        "crons": entries,
+        "count": entries.len()
     }))
 }