Lock in Linux hook stdin BrokenPipe coverage

Latest main already contains the functional BrokenPipe tolerance in
plugins::hooks::CommandWithStdin::output_with_stdin, but the only
coverage for the original CI failure was the higher-level plugin hook
test. Add a deterministic regression that exercises the exact low-level
EPIPE path by spawning a hook child that closes stdin immediately while
the parent writes an oversized payload.

This keeps the real root cause explicit: Linux surfaced BrokenPipe from
the parent's stdin write after the hook child closed fd 0 early. Missing
execute bits were not the primary bug.

Constraint: Keep the change surgical on top of latest main
Rejected: Re-open the production code path | latest main already contains the runtime fix
Rejected: Inflate HookRunner payloads in the regression | HOOK_* env injection hit ARG_MAX before the pipe path
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep BrokenPipe coverage near CommandWithStdin so future refactors do not regress the Linux EPIPE path
Tested: cargo test -p plugins hooks::tests::collects_and_runs_hooks_from_enabled_plugins -- --exact (10x)
Tested: cargo test -p plugins hooks::tests::output_with_stdin_tolerates_broken_pipe_when_child_closes_stdin_early -- --exact (10x)
Tested: cargo test --workspace
Not-tested: GitHub Actions rerun on the PR branch

ROADMAP.md

@@ -194,6 +194,20 @@ Workers should distinguish:
 Acceptance:
 - no more ambiguous "tests passed" messaging
 - merge policy can require the correct green level for the lane type
+- a single hung test must not mask other failures: enforce per-test
+  timeouts in CI (`cargo test --workspace`) so a 6-minute hang in one
+  crate cannot prevent downstream crates from running their suites
+- when a CI job fails because of a hang, the worker must report it as
+  `test.hung` rather than a generic failure, so triage doesn't conflate
+  it with a normal `assertion failed`
+- recorded pinpoint (2026-04-08): `be561bf` swapped the local
+  byte-estimate preflight for a `count_tokens` round-trip and silently
+  returned `Ok(())` on any error, so `send_message_blocks_oversized_*`
+  hung for ~6 minutes per attempt; the resulting workspace job crash
+  hid 6 *separate* pre-existing CLI regressions (compact flag
+  discarded, piped stdin vs permission prompter, legacy session layout,
+  help/prompt assertions, mock harness count) that only became
+  diagnosable after `8c6dfe5` + `5851f2d` restored the fast-fail path
 
 ## Phase 4 — Claws-First Task Execution
 
@@ -307,11 +321,16 @@ Priority order: P0 = blocks CI/green state, P1 = blocks integration wiring, P2 =
 18. **Context-window preflight gap** — **done**: provider request sizing now emits `context_window_blocked` before oversized requests leave the process, using a model-context registry instead of the old naive max-token heuristic.
 19. **Subcommand help falls through into runtime/API path** — **done**: `claw doctor --help`, `claw status --help`, `claw sandbox --help`, and nested `mcp`/`skills` help are now intercepted locally without runtime/provider startup, with regression tests covering the direct CLI paths.
 20. **Session state classification gap (working vs blocked vs finished vs truly stale)** — **done**: agent manifests now derive machine states such as `working`, `blocked_background_job`, `blocked_merge_conflict`, `degraded_mcp`, `interrupted_transport`, `finished_pending_report`, and `finished_cleanable`, and terminal-state persistence records commit provenance plus derived state so downstream monitoring can distinguish quiet progress from truly idle sessions.
-21. **Resumed `/status` JSON parity gap** — dogfooding shows fresh `claw status --output-format json` now emits structured JSON, but resumed slash-command status still leaks through a text-shaped path in at least one dispatch path. Local CI-equivalent repro fails `rust/crates/rusty-claude-cli/tests/resume_slash_commands.rs::resumed_status_command_emits_structured_json_when_requested` with `expected value at line 1 column 1`, so resumed automation can receive text where JSON was explicitly requested. **Action:** unify fresh vs resumed `/status` rendering through one output-format contract and add regression coverage so resumed JSON output is guaranteed valid.
+21. **Resumed `/status` JSON parity gap** — **done**: resolved by the broader "Resumed local-command JSON parity gap" work tracked as #26 below. Re-verified on `main` HEAD `8dc6580` — `cargo test --release -p rusty-claude-cli resumed_status_command_emits_structured_json_when_requested` passes cleanly (1 passed, 0 failed), so resumed `/status --output-format json` now goes through the same structured renderer as the fresh CLI path. The original failure (`expected value at line 1 column 1` because resumed dispatch fell back to prose) no longer reproduces.
 22. **Opaque failure surface for session/runtime crashes** — **done**: `safe_failure_class()` in `error.rs` classifies all API errors into 8 user-safe classes (`provider_auth`, `provider_internal`, `provider_retry_exhausted`, `provider_rate_limit`, `provider_transport`, `provider_error`, `context_window`, `runtime_io`). `format_user_visible_api_error` in `main.rs` attaches session ID + request trace ID to every user-visible error. Coverage in `opaque_provider_wrapper_surfaces_failure_class_session_and_trace` and 3 related tests.
 23. **`doctor --output-format json` check-level structure gap** — **done**: `claw doctor --output-format json` now keeps the human-readable `message`/`report` while also emitting structured per-check diagnostics (`name`, `status`, `summary`, `details`, plus typed fields like workspace paths and sandbox fallback data), with regression coverage in `output_format_contract.rs`.
 24. **Plugin lifecycle init/shutdown test flakes under workspace-parallel execution** — dogfooding surfaced that `build_runtime_runs_plugin_lifecycle_init_and_shutdown` can fail under `cargo test --workspace` while passing in isolation because sibling tests race on tempdir-backed shell init script paths. This is test brittleness rather than a code-path regression, but it still destabilizes CI confidence and wastes diagnosis cycles. **Action:** isolate temp resources per test robustly (unique dirs + no shared cwd assumptions), audit cleanup timing, and add a regression guard so the plugin lifecycle test remains stable under parallel workspace execution.
+25. **`plugins::hooks::collects_and_runs_hooks_from_enabled_plugins` flaked on Linux CI, root cause was a stdin-write race not missing exec bit** — **done at `172a2ad` on 2026-04-08**. Dogfooding reproduced this four times on `main` (CI runs [24120271422](https://github.com/ultraworkers/claw-code/actions/runs/24120271422), [24120538408](https://github.com/ultraworkers/claw-code/actions/runs/24120538408), [24121392171](https://github.com/ultraworkers/claw-code/actions/runs/24121392171), [24121776826](https://github.com/ultraworkers/claw-code/actions/runs/24121776826)), escalating from first-attempt-flake to deterministic-red on the third push. Failure mode was `PostToolUse hook .../hooks/post.sh failed to start for "Read": Broken pipe (os error 32)` surfacing from `HookRunResult`. **Initial diagnosis was wrong.** The first theory (documented in earlier revisions of this entry and in the root-cause note on commit `79da4b8`) was that `write_hook_plugin` in `rust/crates/plugins/src/hooks.rs` was writing the generated `.sh` files without the execute bit and `Command::new(path).spawn()` was racing on fork/exec. An initial chmod-only fix at `4f7b674` was shipped against that theory and **still failed CI on run `24121776826`** with the same `Broken pipe` symptom, falsifying the chmod-only hypothesis. **Actual root cause.** `CommandWithStdin::output_with_stdin` in `rust/crates/plugins/src/hooks.rs` was unconditionally propagating `write_all` errors on the child's stdin pipe, including `std::io::ErrorKind::BrokenPipe`. The test hook scripts run in microseconds (`#!/bin/sh` + a single `printf`), so the child exits and closes its stdin before the parent finishes writing the ~200-byte JSON hook payload. On Linux the pipe raises `EPIPE` immediately; on macOS the pipe happens to buffer the small payload before the child exits, which is why the race only surfaced on ubuntu CI runners. The parent's `write_all` returned `Err(BrokenPipe)`, `output_with_stdin` returned that as a hook failure, and `run_command` classified the hook as "failed to start" even though the child had already run to completion and printed the expected message to stdout. **Fix (commit `172a2ad`, force-pushed over `4f7b674`).** Three parts: (1) **actual fix** — `output_with_stdin` now matches the `write_all` result and swallows `BrokenPipe` specifically, while propagating all other write errors unchanged; after a `BrokenPipe` swallow the code still calls `wait_with_output()` so stdout/stderr/exit code are still captured from the cleanly-exited child. (2) **hygiene hardening** — a new `make_executable` helper sets mode `0o755` on each generated `.sh` via `std::os::unix::fs::PermissionsExt` under `#[cfg(unix)]`. This is defense-in-depth for future non-sh hook runners, not the bug that was biting CI. (3) **regression guard** — new `generated_hook_scripts_are_executable` test under `#[cfg(unix)]` asserts each generated `.sh` file has at least one execute bit set (`mode & 0o111 != 0`) so future tweaks cannot silently regress the hygiene change. **Verification.** `cargo test --release -p plugins` 35 passing, fmt clean, clippy `-D warnings` clean; CI run [24121999385](https://github.com/ultraworkers/claw-code/actions/runs/24121999385) went green on first attempt on `main` for the hotfix commit. **Meta-lesson.** `Broken pipe (os error 32)` from a child-process spawn path is ambiguous between "could not exec" and "exec'd and exited before the parent finished writing stdin." The first theory cargo-culted the "could not exec" reading because the ROADMAP scaffolding anchored on the exec-bit guess; falsification came from empirical CI, not from code inspection. Record the pattern: when a pipe error surfaces on fork/exec, instrument what `wait_with_output()` actually reports on the child before attributing the failure to a permissions or path issue.
 26. **Resumed local-command JSON parity gap** — **done**: direct `claw --output-format json` already had structured renderers for `sandbox`, `mcp`, `skills`, `version`, and `init`, but resumed `claw --output-format json --resume <session> /…` paths still fell back to prose because resumed slash dispatch only emitted JSON for `/status`. Resumed `/sandbox`, `/mcp`, `/skills`, `/version`, and `/init` now reuse the same JSON envelopes as their direct CLI counterparts, with regression coverage in `rust/crates/rusty-claude-cli/tests/resume_slash_commands.rs` and `rust/crates/rusty-claude-cli/tests/output_format_contract.rs`.
+27. **`dev/rust` `cargo test -p rusty-claude-cli` reads host `~/.claude/plugins/installed/` from real `$HOME` and fails parse-time on any half-installed user plugin** — dogfooding on 2026-04-08 (filed from gaebal-gajae's clawhip bullet at message `1491322807026454579` after the provider-matrix branch QA surfaced it) reproduced 11 deterministic failures on clean `dev/rust` HEAD of the form `panicked at crates/rusty-claude-cli/src/main.rs:3953:31: args should parse: "hook path \`/Users/yeongyu/.claude/plugins/installed/sample-hooks-bundled/./hooks/pre.sh\` does not exist; hook path \`...\post.sh\` does not exist"` covering `parses_prompt_subcommand`, `parses_permission_mode_flag`, `defaults_to_repl_when_no_args`, `parses_resume_flag_with_slash_command`, `parses_system_prompt_options`, `parses_bare_prompt_and_json_output_flag`, `rejects_unknown_allowed_tools`, `parses_resume_flag_with_multiple_slash_commands`, `resolves_model_aliases_in_args`, `parses_allowed_tools_flags_with_aliases_and_lists`, `parses_login_and_logout_subcommands`. **Same failures do NOT reproduce on `main`** (re-verified with `cargo test --release -p rusty-claude-cli` against `main` HEAD `79da4b8`, all 156 tests pass). **Root cause is two-layered.** First, on `dev/rust` `parse_args` eagerly walks user-installed plugin manifests under `~/.claude/plugins/installed/` and validates that every declared hook script exists on disk before returning a `CliAction`, so any half-installed plugin in the developer's real `$HOME` (in this case `~/.claude/plugins/installed/sample-hooks-bundled/` whose `.claude-plugin` manifest references `./hooks/pre.sh` and `./hooks/post.sh` but whose `hooks/` subdirectory was deleted) makes argv parsing itself fail. Second, the test harness on `dev/rust` does not redirect `$HOME` or `XDG_CONFIG_HOME` to a fixture for the duration of the test — there is no `env_lock`-style guard equivalent to the one `main` already uses (`grep -n env_lock rust/crates/rusty-claude-cli/src/main.rs` returns 0 hits on `dev/rust` and 30+ hits on `main`). Together those two gaps mean `dev/rust` `cargo test -p rusty-claude-cli` is non-deterministic on every clean clone whose owner happens to have any non-pristine plugin in `~/.claude/`. **Action (two parts).** (a) Backport the `env_lock`-based test isolation pattern from `main` into `dev/rust`'s `rusty-claude-cli` test module so each test runs against a temp `$HOME`/`XDG_CONFIG_HOME` and cannot read host plugin state. (b) Decouple `parse_args` from filesystem hook validation on `dev/rust` (the same decoupling already on `main`, where hook validation happens later in the lifecycle than argv parsing) so even outside tests a partially installed user plugin cannot break basic CLI invocation. **Branch scope.** This is a `dev/rust` catchup against `main`, not a `main` regression. Tracking it here so the dev/rust merge train picks it up before the next dev/rust release rather than rediscovering it in CI.
+
+28. **Auth-provider truth: error copy fails real users at the env-var-vs-header layer** — dogfooded live on 2026-04-08 in #claw-code (Sisyphus Labs guild), two separate new users hit adjacent failure modes within minutes of each other that both trace back to the same root: the `MissingApiKey` / 401 error surface does not teach users how the auth inputs map to HTTP semantics, so a user who sets a "reasonable-looking" env var still hits a hard error with no signpost. **Case 1 (varleg, Norway).** Wanted to use OpenRouter via the OpenAI-compat path. Found a comparison table claiming "provider-agnostic (Claude, OpenAI, local models)" and assumed it Just Worked. Set `OPENAI_API_KEY` to an OpenRouter `sk-or-v1-...` key and a model name without an `openai/` prefix; claw's provider detection fell through to Anthropic first because `ANTHROPIC_API_KEY` was still in the environment. Unsetting `ANTHROPIC_API_KEY` got them `ANTHROPIC_AUTH_TOKEN or ANTHROPIC_API_KEY is not set` instead of a useful hint that the OpenAI path was right there. Fix delivered live as a channel reply: use `main` branch (not `dev/rust`), export `OPENAI_BASE_URL=https://openrouter.ai/api/v1` alongside `OPENAI_API_KEY`, and prefix the model name with `openai/` so the prefix router wins over env-var presence. **Case 2 (stanley078852).** Had set `ANTHROPIC_AUTH_TOKEN="sk-ant-..."` and was getting 401 `Invalid bearer token` from Anthropic. Root cause: `sk-ant-` keys are `x-api-key`-header keys, not bearer tokens. `ANTHROPIC_API_KEY` path in `anthropic.rs` sends the value as `x-api-key`; `ANTHROPIC_AUTH_TOKEN` path sends it as `Authorization: Bearer` (for OAuth access tokens from `claw login`). Setting an `sk-ant-` key in the wrong env var makes claw send it as `Bearer sk-ant-...` which Anthropic rejects at the edge with 401 before it ever reaches the completions endpoint. The error text propagated all the way to the user (`api returned 401 Unauthorized (authentication_error) ... Invalid bearer token`) with zero signal that the problem was env-var choice, not key validity. Fix delivered live as a channel reply: move the `sk-ant-...` key to `ANTHROPIC_API_KEY` and unset `ANTHROPIC_AUTH_TOKEN`. **Pattern.** Both cases are failures at the *auth-intent translation* layer: the user chose an env var that made syntactic sense to them (`OPENAI_API_KEY` for OpenAI, `ANTHROPIC_AUTH_TOKEN` for Anthropic auth) but the actual wire-format routing requires a more specific choice. The error messages surface the HTTP-layer symptom (401, missing-key) without bridging back to "which env var should you have used and why." **Action.** Three concrete improvements, scoped for a single `main`-side PR: (a) In `ApiError::MissingCredentials` Display, when the Anthropic path is the one being reported but `OPENAI_API_KEY`, `XAI_API_KEY`, or `DASHSCOPE_API_KEY` are present in the environment, extend the message with "— but I see `$OTHER_KEY` set; if you meant to use that provider, prefix your model name with `openai/`, `grok`, or `qwen/` respectively so prefix routing selects it." (b) In the 401-from-Anthropic error path in `anthropic.rs`, when the failing auth source is `BearerToken` AND the bearer token starts with `sk-ant-`, append "— looks like you put an `sk-ant-*` API key in `ANTHROPIC_AUTH_TOKEN`, which is the Bearer-header path. Move it to `ANTHROPIC_API_KEY` instead (that env var maps to `x-api-key`, which is the correct header for `sk-ant-*` keys)." Same treatment for OAuth access tokens landing in `ANTHROPIC_API_KEY` (symmetric mis-assignment). (c) In `rust/README.md` on `main` and the matrix section on `dev/rust`, add a short "Which env var goes where" paragraph mapping `sk-ant-*` → `ANTHROPIC_API_KEY` and OAuth access token → `ANTHROPIC_AUTH_TOKEN`, with the one-line explanation of `x-api-key` vs `Authorization: Bearer`. **Verification path.** Both improvements can be tested with unit tests against `ApiError::fmt` output (the prefix-routing hint) and with a targeted integration test that feeds an `sk-ant-*`-shaped token into `BearerToken` and asserts the fmt output surfaces the correction hint (no HTTP call needed). **Source.** Live users in #claw-code at `1491328554598924389` (varleg) and `1491329840706486376` (stanley078852) on 2026-04-08. **Partial landing (`ff1df4c`).** Action parts (a), (b), (c) shipped on `main`: `MissingCredentials` now carries an optional hint field and renders adjacent-provider signals, Anthropic 401 + `sk-ant-*` bearer gets a correction hint, USAGE.md has a "Which env var goes where" section. BUT the copy fix only helps users who fell through to the Anthropic auth path by accident — it does NOT fix the underlying routing bug where the CLI instantiates `AnthropicRuntimeClient` unconditionally and ignores prefix routing at the runtime-client layer. That deeper routing gap is tracked separately as #29 below and was filed within hours of #28 landing when live users still hit `missing Anthropic credentials` with `--model openai/gpt-4`Line truncated
+29. **CLI provider dispatch is hardcoded to Anthropic, ignoring prefix routing** — **done at `8dc6580` on 2026-04-08**. Changed `AnthropicRuntimeClient.client` from concrete `AnthropicClient` to `ApiProviderClient` (the api crate’s `ProviderClient` enum), which dispatches to Anthropic / xAI / OpenAi at construction time based on `detect_provider_kind(&resolved_model)`. 1 file, +59 −7, all 182 rusty-claude-cli tests pass, CI green at run `24125825431`. Users can now run `claw --model openai/gpt-4.1-mini prompt "hello"` with only `OPENAI_API_KEY` set and it routes correctly. **Original filing below for the trace record.** Dogfooded live on 2026-04-08 within hours of ROADMAP #28 landing. Users in #claw-code (nicma at `1491342350960562277`, Jengro at `1491345009021030533`) followed the exact "use main, set OPENAI_API_KEY and OPENAI_BASE_URL, unset ANTHROPIC_*, prefix the model with `openai/`" checklist from the #28 error-copy improvements AND STILL hit `error: missing Anthropic credentials; export ANTHROPIC_AUTH_TOKEN or ANTHROPIC_API_KEY before calling the Anthropic API`. **Reproduction on `main` HEAD `ff1df4c`:** `unset ANTHROPIC_API_KEY ANTHROPIC_AUTH_TOKEN; export OPENAI_API_KEY=sk-...; export OPENAI_BASE_URL=https://api.openai.com/v1; claw --model openai/gpt-4 prompt 'test'` → reproduces the error deterministically. **Root cause (traced).** `rust/crates/rusty-claude-cli/src/main.rs` at `build_runtime_with_plugin_state` (line ~6221) unconditionally builds `AnthropicRuntimeClient::new(session_id, model, ...)` without consulting `providers::detect_provider_kind(&model)`. `BuiltRuntime` at line ~2855 is statically typed as `ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>`, so even if the dispatch logic existed there would be nowhere to slot an alternative client. `providers/mod.rs::metadata_for_model` correctly identifies `openai/gpt-4` as `ProviderKind::OpenAi` at the metadata layer — the routing decision is *computed* correctly, it's just *never used* to pick a runtime client. The result is that the CLI is structurally single-provider (Anthropic only) even though the `api` crate's `openai_compat.rs`, `XAI_ENV_VARS`, `DASHSCOPE_ENV_VARS`, and `send_message_streaming` all exist and are exercised by unit tests inside the `api` crate. The provider matrix in `rust/README.md` is misleading because it describes the api-crate capabilities, not the CLI's actual dispatch behaviour. **Why #28 didn't catch this.** ROADMAP #28 focused on the `MissingCredentials` error *message* (adding hints when adjacent provider env vars are set, or when a bearer token starts with `sk-ant-*`). None of its tests exercised the `build_runtime` code path — they were all unit tests against `ApiError::fmt` output. The routing bug survives #28 because the `Display` improvements fire AFTER the hardcoded Anthropic client has already been constructed and failed. You need the CLI to dispatch to a different client in the first place for the new hints to even surface at the right moment. **Action (single focused commit).** (1) New `OpenAiCompatRuntimeClient` struct in `rust/crates/rusty-claude-cli/src/main.rs` mirroring `AnthropicRuntimeClient` but delegating to `openai_compat::send_message_streaming`. One client type handles OpenAI, xAI, DashScope, and any OpenAI-compat endpoint — they differ only in base URL and auth env var, both of which come from the `ProviderMetadata` returned by `metadata_for_model`. (2) New enum `DynamicApiClient { Anthropic(AnthropicRuntimeClient), OpenAiCompat(OpenAiCompatRuntimeClient) }` that implements `runtime::ApiClient` by matching on the variant and delegating. (3) Retype `BuiltRuntime` from `ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>` to `ConversationRuntime<DynamicApiClient, CliToolExecutor>`, update the Deref/DerefMut/new spots. (4) In `build_runtime_with_plugin_state`, call `detect_provider_kind(&model)` and construct either variant of `DynamicApiClient`. Prefix routing wins over env-var presence (that's the whole point). (5) Integration test using a mock OpenAI-compat server (reuse `mock_parity_harness` pattern from `crates/api/tests/`) that feeds `claw --model openai/gpt-4 prompt 'test'` with `OPENAI_BASE_URL` pointed at the mock and no `ANTHROPIC_*` env vars, asserts the request reaches the mock, and asserts the response round-trips as an `AssistantEvent`. (6) Unit test that `build_runtime_with_plugin_state` with `model="openai/gpt-4"` returns a `BuiltRuntime` whose inner client is the `DynamicApiClient::OpenAiCompat` variant. **Verification.** `cargo test --workspace`, `cargo fmt --all`, `cargo clippy --workspace`. **Source.** Live users nicma (`1491342350960562277`) and Jengro (`1491345009021030533`) in #claw-code on 2026-04-08, within hours of #28 landing.
 
 41. **Phantom completions root cause: global session store has no per-worktree isolation** —
 
@@ -459,3 +478,13 @@ If `ANTHROPIC_API_KEY` was present in the environment (e.g. user has both Anthro
 Model name prefix now wins unconditionally over env-var presence. Regression test locked in: `providers::tests::openai_namespaced_model_routes_to_openai_not_anthropic`.
 
 **Lesson:** Auth-sniffer fallback order is fragile. Any new provider added in the future should be registered in `metadata_for_model` via a model-name prefix, not left to env-var order. This is the canonical extension point.
+
+30. **DashScope model routing in ProviderClient dispatch uses wrong config** — **done at `adcea6b` on 2026-04-08**. `ProviderClient::from_model_with_anthropic_auth` dispatched all `ProviderKind::OpenAi` matches to `OpenAiCompatConfig::openai()` (reads `OPENAI_API_KEY`, points at `api.openai.com`). But DashScope models (`qwen-plus`, `qwen/qwen-max`) return `ProviderKind::OpenAi` because DashScope speaks the OpenAI wire format — they need `OpenAiCompatConfig::dashscope()` (reads `DASHSCOPE_API_KEY`, points at `dashscope.aliyuncs.com/compatible-mode/v1`). Fix: consult `metadata_for_model` in the `OpenAi` dispatch arm and pick `dashscope()` vs `openai()` based on `metadata.auth_env`. Adds regression test + `pub base_url()` accessor. 2 files, +94/−3. Authored by droid (Kimi K2.5 Turbo) via acpx, cleaned up by Jobdori.
+
+31. **`code-on-disk → verified commit lands` depends on undocumented executor quirks** — dogfooded 2026-04-08 during live fix session. Three hidden contracts tripped the "last mile" path when using droid via acpx in the claw-code workspace: **(a) hidden CWD contract** — droid's `terminal/create` rejects `cd /path && cargo build` compound commands with `spawn ENOENT`; callers must pass `--cwd` or split commands; **(b) hidden commit-message transport limit** — embedding a multi-line commit message in a single shell invocation hits `ENAMETOOLONG`; workaround is `git commit -F <file>` but the caller must know to write the file first; **(c) hidden workspace lint/edition contract** — `unsafe_code = "forbid"` workspace-wide with Rust 2021 edition makes `unsafe {}` wrappers incorrect for `set_var`/`remove_var`, but droid generates Rust 2024-style unsafe blocks without inspecting the workspace Cargo.toml or clippy config. Each of these required the orchestrator to learn the constraint by failing, then switching strategies. **Acceptance bar:** a fresh agent should be able to verify/commit/push a correct diff in this workspace without needing to know executor-specific shell trivia ahead of time. **Fix shape:** (1) `run-acpx.sh`-style wrapper that normalizes the commit idiom (always writes to temp file, sets `--cwd`, splits compound commands); (2) inject workspace constraints into the droid/acpx task preamble (edition, lint gates, known shell executor quirks) so the model doesn't have to discover them from failures; (3) or upstream a fix to the executor itself so `cd /path && cmd` chains work correctly.
+
+32. **OpenAI-compatible provider/model-id passthrough is not fully literal** — dogfooded 2026-04-08 via live user in #claw-code who confirmed the exact backend model id works outside claw but fails through claw for an OpenAI-compatible endpoint. The gap: `openai/` prefix is correctly used for **transport selection** (pick the OpenAI-compat client) but the **wire model id** — the string placed in `"model": "..."` in the JSON request body — may not be the literal backend model string the user supplied. Two candidate failure modes: **(a)** `resolve_model_alias()` is called on the model string before it reaches the wire — alias expansion designed for Anthropic/known models corrupts a user-supplied backend-specific id; **(b)** the `openai/` routing prefix may not be stripped before `build_chat_completion_request` packages the body, so backends receive `openai/gpt-4` instead of `gpt-4`. **Fix shape:** cleanly separate transport selection from wire model id. Transport selection uses the prefix; wire model id is the user-supplied string minus only the routing prefix — no alias expansion, no prefix leakage. **Trace path for next session:** (1) find where `resolve_model_alias()` is called relative to the OpenAI-compat dispatch path; (2) inspect what `build_chat_completion_request` puts in `"model"` for an `openai/some-backend-id` input. **Source:** live user in #claw-code 2026-04-08, confirmed exact model id works outside claw, fails through claw for OpenAI-compat backend.
+
+32. **OpenAI-compatible provider/model-id passthrough is not fully literal** — dogfooded 2026-04-08 via live user in #claw-code who confirmed the exact backend model id works outside claw but fails through claw for an OpenAI-compatible endpoint. The gap: `openai/` prefix is correctly used for **transport selection** (pick the OpenAI-compat client) but the **wire model id** — the string placed in `"model": "..."` in the JSON request body — may not be the literal backend model string the user supplied. Two candidate failure modes: **(a)** `resolve_model_alias()` is called on the model string before it reaches the wire — alias expansion designed for Anthropic/known models corrupts a user-supplied backend-specific id; **(b)** the `openai/` routing prefix may not be stripped before `build_chat_completion_request` packages the body, so backends receive `openai/gpt-4` instead of `gpt-4`. **Fix shape:** cleanly separate transport selection from wire model id. Transport selection uses the prefix; wire model id is the user-supplied string minus only the routing prefix — no alias expansion, no prefix leakage. **Trace path for next session:** (1) find where `resolve_model_alias()` is called relative to the OpenAI-compat dispatch path; (2) inspect what `build_chat_completion_request` puts in `"model"` for an `openai/some-backend-id` input. **Source:** live user in #claw-code 2026-04-08, confirmed exact model id works outside claw, fails through claw for OpenAI-compat backend.
+
+32. **OpenAI-compatible provider/model-id passthrough is not fully literal** — dogfooded 2026-04-08 via live user in #claw-code who confirmed the exact backend model id works outside claw but fails through claw for an OpenAI-compatible endpoint. The gap: `openai/` prefix is correctly used for **transport selection** (pick the OpenAI-compat client) but the **wire model id** — the string placed in `"model": "..."` in the JSON request body — may not be the literal backend model string the user supplied. Two candidate failure modes: **(a)** `resolve_model_alias()` is called on the model string before it reaches the wire — alias expansion designed for Anthropic/known models corrupts a user-supplied backend-specific id; **(b)** the `openai/` routing prefix may not be stripped before `build_chat_completion_request` packages the body, so backends receive `openai/gpt-4` instead of `gpt-4`. **Fix shape:** cleanly separate transport selection from wire model id. Transport selection uses the prefix; wire model id is the user-supplied string minus only the routing prefix — no alias expansion, no prefix leakage. **Trace path for next session:** (1) find where `resolve_model_alias()` is called relative to the OpenAI-compat dispatch path; (2) inspect what `build_chat_completion_request` puts in `"model"` for an `openai/some-backend-id` input. **Source:** live user in #claw-code 2026-04-08, confirmed exact model id works outside claw, fails through claw for OpenAI-compat backend.

USAGE.md

@@ -109,6 +109,20 @@ cd rust
 ./target/debug/claw logout
 ```
 
+### Which env var goes where
+
+`claw` accepts two Anthropic credential env vars and they are **not interchangeable** — the HTTP header Anthropic expects differs per credential shape. Putting the wrong value in the wrong slot is the most common 401 we see.
+
+| Credential shape | Env var | HTTP header | Typical source |
+|---|---|---|---|
+| `sk-ant-*` API key | `ANTHROPIC_API_KEY` | `x-api-key: sk-ant-...` | [console.anthropic.com](https://console.anthropic.com) |
+| OAuth access token (opaque) | `ANTHROPIC_AUTH_TOKEN` | `Authorization: Bearer ...` | `claw login` or an Anthropic-compatible proxy that mints Bearer tokens |
+| OpenRouter key (`sk-or-v1-*`) | `OPENAI_API_KEY` + `OPENAI_BASE_URL=https://openrouter.ai/api/v1` | `Authorization: Bearer ...` | [openrouter.ai/keys](https://openrouter.ai/keys) |
+
+**Why this matters:** if you paste an `sk-ant-*` key into `ANTHROPIC_AUTH_TOKEN`, Anthropic's API will return `401 Invalid bearer token` because `sk-ant-*` keys are rejected over the Bearer header. The fix is a one-line env var swap — move the key to `ANTHROPIC_API_KEY`. Recent `claw` builds detect this exact shape (401 + `sk-ant-*` in the Bearer slot) and append a hint to the error message pointing at the fix.
+
+**If you meant a different provider:** if `claw` reports missing Anthropic credentials but you already have `OPENAI_API_KEY`, `XAI_API_KEY`, or `DASHSCOPE_API_KEY` exported, you most likely forgot to prefix the model name with the provider's routing prefix. Use `--model openai/gpt-4.1-mini` (OpenAI-compat / OpenRouter / Ollama), `--model grok` (xAI), or `--model qwen-plus` (DashScope) and the prefix router will select the right backend regardless of the ambient credentials. The error message now includes a hint that names the detected env var.
+
 ## Local Models
 
 `claw` can talk to local servers and provider gateways through either Anthropic-compatible or OpenAI-compatible endpoints. Use `ANTHROPIC_BASE_URL` with `ANTHROPIC_AUTH_TOKEN` for Anthropic-compatible services, or `OPENAI_BASE_URL` with `OPENAI_API_KEY` for OpenAI-compatible services. OAuth is Anthropic-only, so when `OPENAI_BASE_URL` is set you should use API-key style auth instead of `claw login`.

rust/crates/api/src/client.rs

@@ -31,9 +31,18 @@ impl ProviderClient {
             ProviderKind::Xai => Ok(Self::Xai(OpenAiCompatClient::from_env(
                 OpenAiCompatConfig::xai(),
             )?)),
-            ProviderKind::OpenAi => Ok(Self::OpenAi(OpenAiCompatClient::from_env(
-                OpenAiCompatConfig::openai(),
-            )?)),
+            ProviderKind::OpenAi => {
+                // DashScope models (qwen-*) also return ProviderKind::OpenAi because they
+                // speak the OpenAI wire format, but they need the DashScope config which
+                // reads DASHSCOPE_API_KEY and points at dashscope.aliyuncs.com.
+                let config = match providers::metadata_for_model(&resolved_model) {
+                    Some(meta) if meta.auth_env == "DASHSCOPE_API_KEY" => {
+                        OpenAiCompatConfig::dashscope()
+                    }
+                    _ => OpenAiCompatConfig::openai(),
+                };
+                Ok(Self::OpenAi(OpenAiCompatClient::from_env(config)?))
+            }
         }
     }
 
@@ -135,8 +144,21 @@ pub fn read_xai_base_url() -> String {
 
 #[cfg(test)]
 mod tests {
+    use std::sync::{Mutex, OnceLock};
+
+    use super::ProviderClient;
     use crate::providers::{detect_provider_kind, resolve_model_alias, ProviderKind};
 
+    /// Serializes every test in this module that mutates process-wide
+    /// environment variables so concurrent test threads cannot observe
+    /// each other's partially-applied state.
+    fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+        LOCK.get_or_init(|| Mutex::new(()))
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+    }
+
     #[test]
     fn resolves_existing_and_grok_aliases() {
         assert_eq!(resolve_model_alias("opus"), "claude-opus-4-6");
@@ -152,4 +174,68 @@ mod tests {
             ProviderKind::Anthropic
         );
     }
+
+    /// Snapshot-restore guard for a single environment variable. Mirrors
+    /// the pattern used in `providers/mod.rs` tests: captures the original
+    /// value on construction, applies the override, and restores on drop so
+    /// tests leave the process env untouched even when they panic.
+    struct EnvVarGuard {
+        key: &'static str,
+        original: Option<std::ffi::OsString>,
+    }
+
+    impl EnvVarGuard {
+        fn set(key: &'static str, value: Option<&str>) -> Self {
+            let original = std::env::var_os(key);
+            match value {
+                Some(value) => std::env::set_var(key, value),
+                None => std::env::remove_var(key),
+            }
+            Self { key, original }
+        }
+    }
+
+    impl Drop for EnvVarGuard {
+        fn drop(&mut self) {
+            match self.original.take() {
+                Some(value) => std::env::set_var(self.key, value),
+                None => std::env::remove_var(self.key),
+            }
+        }
+    }
+
+    #[test]
+    fn dashscope_model_uses_dashscope_config_not_openai() {
+        // Regression: qwen-plus was being routed to OpenAiCompatConfig::openai()
+        // which reads OPENAI_API_KEY and points at api.openai.com, when it should
+        // use OpenAiCompatConfig::dashscope() which reads DASHSCOPE_API_KEY and
+        // points at dashscope.aliyuncs.com.
+        let _lock = env_lock();
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", Some("test-dashscope-key"));
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", None);
+
+        let client = ProviderClient::from_model("qwen-plus");
+
+        // Must succeed (not fail with "missing OPENAI_API_KEY")
+        assert!(
+            client.is_ok(),
+            "qwen-plus with DASHSCOPE_API_KEY set should build successfully, got: {:?}",
+            client.err()
+        );
+
+        // Verify it's the OpenAi variant pointed at the DashScope base URL.
+        match client.unwrap() {
+            ProviderClient::OpenAi(openai_client) => {
+                assert!(
+                    openai_client.base_url().contains("dashscope.aliyuncs.com"),
+                    "qwen-plus should route to DashScope base URL (contains 'dashscope.aliyuncs.com'), got: {}",
+                    openai_client.base_url()
+                );
+            }
+            other => panic!(
+                "Expected ProviderClient::OpenAi for qwen-plus, got: {:?}",
+                other
+            ),
+        }
+    }
 }

rust/crates/api/src/error.rs

@@ -22,6 +22,11 @@ pub enum ApiError {
     MissingCredentials {
         provider: &'static str,
         env_vars: &'static [&'static str],
+        /// Optional, runtime-computed hint appended to the error Display
+        /// output. Populated when the provider resolver can infer what the
+        /// user probably intended (e.g. an OpenAI key is set but Anthropic
+        /// was selected because no Anthropic credentials exist).
+        hint: Option<String>,
     },
     ContextWindowExceeded {
         model: String,
@@ -66,7 +71,29 @@ impl ApiError {
         provider: &'static str,
         env_vars: &'static [&'static str],
     ) -> Self {
-        Self::MissingCredentials { provider, env_vars }
+        Self::MissingCredentials {
+            provider,
+            env_vars,
+            hint: None,
+        }
+    }
+
+    /// Build a `MissingCredentials` error carrying an extra, runtime-computed
+    /// hint string that the Display impl appends after the canonical "missing
+    /// <provider> credentials" message. Used by the provider resolver to
+    /// suggest the likely fix when the user has credentials for a different
+    /// provider already in the environment.
+    #[must_use]
+    pub fn missing_credentials_with_hint(
+        provider: &'static str,
+        env_vars: &'static [&'static str],
+        hint: impl Into<String>,
+    ) -> Self {
+        Self::MissingCredentials {
+            provider,
+            env_vars,
+            hint: Some(hint.into()),
+        }
     }
 
     /// Build a `Self::Json` enriched with the provider name, the model that
@@ -204,7 +231,11 @@ impl ApiError {
 impl Display for ApiError {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::MissingCredentials { provider, env_vars } => {
+            Self::MissingCredentials {
+                provider,
+                env_vars,
+                hint,
+            } => {
                 write!(
                     f,
                     "missing {provider} credentials; export {} before calling the {provider} API",
@@ -223,6 +254,9 @@ impl Display for ApiError {
                         )?;
                     }
                 }
+                if let Some(hint) = hint {
+                    write!(f, " — hint: {hint}")?;
+                }
                 Ok(())
             }
             Self::ContextWindowExceeded {
@@ -483,4 +517,56 @@ mod tests {
         assert_eq!(error.safe_failure_class(), "context_window");
         assert_eq!(error.request_id(), Some("req_ctx_123"));
     }
+
+    #[test]
+    fn missing_credentials_without_hint_renders_the_canonical_message() {
+        // given
+        let error = ApiError::missing_credentials(
+            "Anthropic",
+            &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"],
+        );
+
+        // when
+        let rendered = error.to_string();
+
+        // then
+        assert!(
+            rendered.starts_with(
+                "missing Anthropic credentials; export ANTHROPIC_AUTH_TOKEN or ANTHROPIC_API_KEY before calling the Anthropic API"
+            ),
+            "rendered error should lead with the canonical missing-credential message: {rendered}"
+        );
+        assert!(
+            !rendered.contains(" — hint: "),
+            "no hint should be appended when none is supplied: {rendered}"
+        );
+    }
+
+    #[test]
+    fn missing_credentials_with_hint_appends_the_hint_after_base_message() {
+        // given
+        let error = ApiError::missing_credentials_with_hint(
+            "Anthropic",
+            &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"],
+            "I see OPENAI_API_KEY is set — if you meant to use the OpenAI-compat provider, prefix your model name with `openai/` so prefix routing selects it.",
+        );
+
+        // when
+        let rendered = error.to_string();
+
+        // then
+        assert!(
+            rendered.starts_with("missing Anthropic credentials;"),
+            "hint should be appended, not replace the base message: {rendered}"
+        );
+        let hint_marker = " — hint: I see OPENAI_API_KEY is set — if you meant to use the OpenAI-compat provider, prefix your model name with `openai/` so prefix routing selects it.";
+        assert!(
+            rendered.ends_with(hint_marker),
+            "rendered error should end with the hint: {rendered}"
+        );
+        // Classification semantics are unaffected by the presence of a hint.
+        assert_eq!(error.safe_failure_class(), "provider_auth");
+        assert!(!error.is_retryable());
+        assert_eq!(error.request_id(), None);
+    }
 }

rust/crates/api/src/providers/anthropic.rs

@@ -16,7 +16,9 @@ use crate::error::ApiError;
 use crate::http_client::build_http_client_or_default;
 use crate::prompt_cache::{PromptCache, PromptCacheRecord, PromptCacheStats};
 
-use super::{model_token_limit, resolve_model_alias, Provider, ProviderFuture};
+use super::{
+    anthropic_missing_credentials, model_token_limit, resolve_model_alias, Provider, ProviderFuture,
+};
 use crate::sse::SseParser;
 use crate::types::{MessageDeltaEvent, MessageRequest, MessageResponse, StreamEvent, Usage};
 
@@ -49,10 +51,7 @@ impl AuthSource {
             }),
             (Some(api_key), None) => Ok(Self::ApiKey(api_key)),
             (None, Some(bearer_token)) => Ok(Self::BearerToken(bearer_token)),
-            (None, None) => Err(ApiError::missing_credentials(
-                "Anthropic",
-                &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"],
-            )),
+            (None, None) => Err(anthropic_missing_credentials()),
         }
     }
 
@@ -436,6 +435,7 @@ impl AnthropicClient {
                         last_error = Some(error);
                     }
                     Err(error) => {
+                        let error = enrich_bearer_auth_error(error, &self.auth);
                         self.record_request_failure(attempts, &error);
                         return Err(error);
                     }
@@ -643,10 +643,7 @@ impl AuthSource {
                 }
             }
             Ok(Some(token_set)) => Ok(Self::BearerToken(token_set.access_token)),
-            Ok(None) => Err(ApiError::missing_credentials(
-                "Anthropic",
-                &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"],
-            )),
+            Ok(None) => Err(anthropic_missing_credentials()),
             Err(error) => Err(error),
         }
     }
@@ -690,10 +687,7 @@ where
     }
 
     let Some(token_set) = load_saved_oauth_token()? else {
-        return Err(ApiError::missing_credentials(
-            "Anthropic",
-            &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"],
-        ));
+        return Err(anthropic_missing_credentials());
     };
     if !oauth_token_is_expired(&token_set) {
         return Ok(AuthSource::BearerToken(token_set.access_token));
@@ -790,10 +784,7 @@ fn read_api_key() -> Result<String, ApiError> {
     auth.api_key()
         .or_else(|| auth.bearer_token())
         .map(ToOwned::to_owned)
-        .ok_or(ApiError::missing_credentials(
-            "Anthropic",
-            &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"],
-        ))
+        .ok_or_else(anthropic_missing_credentials)
 }
 
 #[cfg(test)]
@@ -934,6 +925,85 @@ const fn is_retryable_status(status: reqwest::StatusCode) -> bool {
     matches!(status.as_u16(), 408 | 409 | 429 | 500 | 502 | 503 | 504)
 }
 
+/// Anthropic API keys (`sk-ant-*`) are accepted over the `x-api-key` header
+/// and rejected with HTTP 401 "Invalid bearer token" when sent as a Bearer
+/// token via `ANTHROPIC_AUTH_TOKEN`. This happens often enough in the wild
+/// (users copy-paste an `sk-ant-...` key into `ANTHROPIC_AUTH_TOKEN` because
+/// the env var name sounds auth-related) that a bare 401 error is useless.
+/// When we detect this exact shape, append a hint to the error message that
+/// points the user at the one-line fix.
+const SK_ANT_BEARER_HINT: &str = "sk-ant-* keys go in ANTHROPIC_API_KEY (x-api-key header), not ANTHROPIC_AUTH_TOKEN (Bearer header). Move your key to ANTHROPIC_API_KEY.";
+
+fn enrich_bearer_auth_error(error: ApiError, auth: &AuthSource) -> ApiError {
+    let ApiError::Api {
+        status,
+        error_type,
+        message,
+        request_id,
+        body,
+        retryable,
+    } = error
+    else {
+        return error;
+    };
+    if status.as_u16() != 401 {
+        return ApiError::Api {
+            status,
+            error_type,
+            message,
+            request_id,
+            body,
+            retryable,
+        };
+    }
+    let Some(bearer_token) = auth.bearer_token() else {
+        return ApiError::Api {
+            status,
+            error_type,
+            message,
+            request_id,
+            body,
+            retryable,
+        };
+    };
+    if !bearer_token.starts_with("sk-ant-") {
+        return ApiError::Api {
+            status,
+            error_type,
+            message,
+            request_id,
+            body,
+            retryable,
+        };
+    }
+    // Only append the hint when the AuthSource is pure BearerToken. If both
+    // api_key and bearer_token are present (`ApiKeyAndBearer`), the x-api-key
+    // header is already being sent alongside the Bearer header and the 401
+    // is coming from a different cause — adding the hint would be misleading.
+    if auth.api_key().is_some() {
+        return ApiError::Api {
+            status,
+            error_type,
+            message,
+            request_id,
+            body,
+            retryable,
+        };
+    }
+    let enriched_message = match message {
+        Some(existing) => Some(format!("{existing} — hint: {SK_ANT_BEARER_HINT}")),
+        None => Some(format!("hint: {SK_ANT_BEARER_HINT}")),
+    };
+    ApiError::Api {
+        status,
+        error_type,
+        message: enriched_message,
+        request_id,
+        body,
+        retryable,
+    }
+}
+
 /// Remove beta-only body fields that the standard `/v1/messages` and
 /// `/v1/messages/count_tokens` endpoints reject as `Extra inputs are not
 /// permitted`. The `betas` opt-in is communicated via the `anthropic-beta`
@@ -1538,4 +1608,163 @@ mod tests {
             Some("claude-sonnet-4-6")
         );
     }
+
+    #[test]
+    fn enrich_bearer_auth_error_appends_sk_ant_hint_on_401_with_pure_bearer_token() {
+        // given
+        let auth = AuthSource::BearerToken("sk-ant-api03-deadbeef".to_string());
+        let error = crate::error::ApiError::Api {
+            status: reqwest::StatusCode::UNAUTHORIZED,
+            error_type: Some("authentication_error".to_string()),
+            message: Some("Invalid bearer token".to_string()),
+            request_id: Some("req_varleg_001".to_string()),
+            body: String::new(),
+            retryable: false,
+        };
+
+        // when
+        let enriched = super::enrich_bearer_auth_error(error, &auth);
+
+        // then
+        let rendered = enriched.to_string();
+        assert!(
+            rendered.contains("Invalid bearer token"),
+            "existing provider message should be preserved: {rendered}"
+        );
+        assert!(
+            rendered.contains(
+                "sk-ant-* keys go in ANTHROPIC_API_KEY (x-api-key header), not ANTHROPIC_AUTH_TOKEN (Bearer header). Move your key to ANTHROPIC_API_KEY."
+            ),
+            "rendered error should include the sk-ant-* hint: {rendered}"
+        );
+        assert!(
+            rendered.contains("[trace req_varleg_001]"),
+            "request id should still flow through the enriched error: {rendered}"
+        );
+        match enriched {
+            crate::error::ApiError::Api { status, .. } => {
+                assert_eq!(status, reqwest::StatusCode::UNAUTHORIZED);
+            }
+            other => panic!("expected Api variant, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn enrich_bearer_auth_error_leaves_non_401_errors_unchanged() {
+        // given
+        let auth = AuthSource::BearerToken("sk-ant-api03-deadbeef".to_string());
+        let error = crate::error::ApiError::Api {
+            status: reqwest::StatusCode::INTERNAL_SERVER_ERROR,
+            error_type: Some("api_error".to_string()),
+            message: Some("internal server error".to_string()),
+            request_id: None,
+            body: String::new(),
+            retryable: true,
+        };
+
+        // when
+        let enriched = super::enrich_bearer_auth_error(error, &auth);
+
+        // then
+        let rendered = enriched.to_string();
+        assert!(
+            !rendered.contains("sk-ant-*"),
+            "non-401 errors must not be annotated with the bearer hint: {rendered}"
+        );
+        assert!(
+            rendered.contains("internal server error"),
+            "original message must be preserved verbatim: {rendered}"
+        );
+    }
+
+    #[test]
+    fn enrich_bearer_auth_error_ignores_401_when_bearer_token_is_not_sk_ant() {
+        // given
+        let auth = AuthSource::BearerToken("oauth-access-token-opaque".to_string());
+        let error = crate::error::ApiError::Api {
+            status: reqwest::StatusCode::UNAUTHORIZED,
+            error_type: Some("authentication_error".to_string()),
+            message: Some("Invalid bearer token".to_string()),
+            request_id: None,
+            body: String::new(),
+            retryable: false,
+        };
+
+        // when
+        let enriched = super::enrich_bearer_auth_error(error, &auth);
+
+        // then
+        let rendered = enriched.to_string();
+        assert!(
+            !rendered.contains("sk-ant-*"),
+            "oauth-style bearer tokens must not trigger the sk-ant-* hint: {rendered}"
+        );
+    }
+
+    #[test]
+    fn enrich_bearer_auth_error_skips_hint_when_api_key_header_is_also_present() {
+        // given
+        let auth = AuthSource::ApiKeyAndBearer {
+            api_key: "sk-ant-api03-legitimate".to_string(),
+            bearer_token: "sk-ant-api03-deadbeef".to_string(),
+        };
+        let error = crate::error::ApiError::Api {
+            status: reqwest::StatusCode::UNAUTHORIZED,
+            error_type: Some("authentication_error".to_string()),
+            message: Some("Invalid bearer token".to_string()),
+            request_id: None,
+            body: String::new(),
+            retryable: false,
+        };
+
+        // when
+        let enriched = super::enrich_bearer_auth_error(error, &auth);
+
+        // then
+        let rendered = enriched.to_string();
+        assert!(
+            !rendered.contains("sk-ant-*"),
+            "hint should be suppressed when x-api-key header is already being sent: {rendered}"
+        );
+    }
+
+    #[test]
+    fn enrich_bearer_auth_error_ignores_401_when_auth_source_has_no_bearer() {
+        // given
+        let auth = AuthSource::ApiKey("sk-ant-api03-legitimate".to_string());
+        let error = crate::error::ApiError::Api {
+            status: reqwest::StatusCode::UNAUTHORIZED,
+            error_type: Some("authentication_error".to_string()),
+            message: Some("Invalid x-api-key".to_string()),
+            request_id: None,
+            body: String::new(),
+            retryable: false,
+        };
+
+        // when
+        let enriched = super::enrich_bearer_auth_error(error, &auth);
+
+        // then
+        let rendered = enriched.to_string();
+        assert!(
+            !rendered.contains("sk-ant-*"),
+            "bearer hint must not apply when AuthSource is ApiKey-only: {rendered}"
+        );
+    }
+
+    #[test]
+    fn enrich_bearer_auth_error_passes_non_api_errors_through_unchanged() {
+        // given
+        let auth = AuthSource::BearerToken("sk-ant-api03-deadbeef".to_string());
+        let error = crate::error::ApiError::InvalidSseFrame("unterminated event");
+
+        // when
+        let enriched = super::enrich_bearer_auth_error(error, &auth);
+
+        // then
+        assert!(matches!(
+            enriched,
+            crate::error::ApiError::InvalidSseFrame(_)
+        ));
+    }
 }

rust/crates/api/src/providers/mod.rs

@@ -291,6 +291,73 @@ fn estimate_serialized_tokens<T: Serialize>(value: &T) -> u32 {
         .map_or(0, |bytes| (bytes.len() / 4 + 1) as u32)
 }
 
+/// Env var names used by other provider backends. When Anthropic auth
+/// resolution fails we sniff these so we can hint the user that their
+/// credentials probably belong to a different provider and suggest the
+/// model-prefix routing fix that would select it.
+const FOREIGN_PROVIDER_ENV_VARS: &[(&str, &str, &str)] = &[
+    (
+        "OPENAI_API_KEY",
+        "OpenAI-compat",
+        "prefix your model name with `openai/` (e.g. `--model openai/gpt-4.1-mini`) so prefix routing selects the OpenAI-compatible provider, and set `OPENAI_BASE_URL` if you are pointing at OpenRouter/Ollama/a local server",
+    ),
+    (
+        "XAI_API_KEY",
+        "xAI",
+        "use an xAI model alias (e.g. `--model grok` or `--model grok-mini`) so the prefix router selects the xAI backend",
+    ),
+    (
+        "DASHSCOPE_API_KEY",
+        "Alibaba DashScope",
+        "prefix your model name with `qwen/` or `qwen-` (e.g. `--model qwen-plus`) so prefix routing selects the DashScope backend",
+    ),
+];
+
+/// Check whether an env var is set to a non-empty value either in the real
+/// process environment or in the working-directory `.env` file. Mirrors the
+/// credential discovery path used by `read_env_non_empty` so the hint text
+/// stays truthful when users rely on `.env` instead of a real export.
+fn env_or_dotenv_present(key: &str) -> bool {
+    match std::env::var(key) {
+        Ok(value) if !value.is_empty() => true,
+        Ok(_) | Err(std::env::VarError::NotPresent) => {
+            dotenv_value(key).is_some_and(|value| !value.is_empty())
+        }
+        Err(_) => false,
+    }
+}
+
+/// Produce a hint string describing the first foreign provider credential
+/// that is present in the environment when Anthropic auth resolution has
+/// just failed. Returns `None` when no foreign credential is set, in which
+/// case the caller should fall back to the plain `missing_credentials`
+/// error without a hint.
+pub(crate) fn anthropic_missing_credentials_hint() -> Option<String> {
+    for (env_var, provider_label, fix_hint) in FOREIGN_PROVIDER_ENV_VARS {
+        if env_or_dotenv_present(env_var) {
+            return Some(format!(
+                "I see {env_var} is set — if you meant to use the {provider_label} provider, {fix_hint}."
+            ));
+        }
+    }
+    None
+}
+
+/// Build an Anthropic-specific `MissingCredentials` error, attaching a
+/// hint suggesting the probable fix whenever a different provider's
+/// credentials are already present in the environment. Anthropic call
+/// sites should prefer this helper over `ApiError::missing_credentials`
+/// so users who mistyped a model name or forgot the prefix get a useful
+/// signal instead of a generic "missing Anthropic credentials" wall.
+pub(crate) fn anthropic_missing_credentials() -> ApiError {
+    const PROVIDER: &str = "Anthropic";
+    const ENV_VARS: &[&str] = &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"];
+    match anthropic_missing_credentials_hint() {
+        Some(hint) => ApiError::missing_credentials_with_hint(PROVIDER, ENV_VARS, hint),
+        None => ApiError::missing_credentials(PROVIDER, ENV_VARS),
+    }
+}
+
 /// Parse a `.env` file body into key/value pairs using a minimal `KEY=VALUE`
 /// grammar. Lines that are blank, start with `#`, or do not contain `=` are
 /// ignored. Surrounding double or single quotes are stripped from the value.
@@ -348,6 +415,9 @@ pub(crate) fn dotenv_value(key: &str) -> Option<String> {
 
 #[cfg(test)]
 mod tests {
+    use std::ffi::OsString;
+    use std::sync::{Mutex, OnceLock};
+
     use serde_json::json;
 
     use crate::error::ApiError;
@@ -356,11 +426,52 @@ mod tests {
     };
 
     use super::{
-        detect_provider_kind, load_dotenv_file, max_tokens_for_model,
-        max_tokens_for_model_with_override, model_token_limit, parse_dotenv,
-        preflight_message_request, resolve_model_alias, ProviderKind,
+        anthropic_missing_credentials, anthropic_missing_credentials_hint, detect_provider_kind,
+        load_dotenv_file, max_tokens_for_model, max_tokens_for_model_with_override,
+        model_token_limit, parse_dotenv, preflight_message_request, resolve_model_alias,
+        ProviderKind,
     };
 
+    /// Serializes every test in this module that mutates process-wide
+    /// environment variables so concurrent test threads cannot observe
+    /// each other's partially-applied state while probing the foreign
+    /// provider credential sniffer.
+    fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+        LOCK.get_or_init(|| Mutex::new(()))
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+    }
+
+    /// Snapshot-restore guard for a single environment variable. Captures
+    /// the original value on construction, applies the requested override
+    /// (set or remove), and restores the original on drop so tests leave
+    /// the process env untouched even when they panic mid-assertion.
+    struct EnvVarGuard {
+        key: &'static str,
+        original: Option<OsString>,
+    }
+
+    impl EnvVarGuard {
+        fn set(key: &'static str, value: Option<&str>) -> Self {
+            let original = std::env::var_os(key);
+            match value {
+                Some(value) => std::env::set_var(key, value),
+                None => std::env::remove_var(key),
+            }
+            Self { key, original }
+        }
+    }
+
+    impl Drop for EnvVarGuard {
+        fn drop(&mut self) {
+            match self.original.take() {
+                Some(value) => std::env::set_var(self.key, value),
+                None => std::env::remove_var(self.key),
+            }
+        }
+    }
+
     #[test]
     fn resolves_grok_aliases() {
         assert_eq!(resolve_model_alias("grok"), "grok-3");
@@ -649,4 +760,225 @@ NO_EQUALS_LINE
 
         let _ = std::fs::remove_dir_all(&temp_root);
     }
+
+    #[test]
+    fn anthropic_missing_credentials_hint_is_none_when_no_foreign_creds_present() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", None);
+        let _xai = EnvVarGuard::set("XAI_API_KEY", None);
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", None);
+
+        // when
+        let hint = anthropic_missing_credentials_hint();
+
+        // then
+        assert!(
+            hint.is_none(),
+            "no hint should be produced when every foreign provider env var is absent, got {hint:?}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_hint_detects_openai_api_key_and_recommends_openai_prefix() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", Some("sk-openrouter-varleg"));
+        let _xai = EnvVarGuard::set("XAI_API_KEY", None);
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", None);
+
+        // when
+        let hint = anthropic_missing_credentials_hint()
+            .expect("OPENAI_API_KEY presence should produce a hint");
+
+        // then
+        assert!(
+            hint.contains("OPENAI_API_KEY is set"),
+            "hint should name the detected env var so users recognize it: {hint}"
+        );
+        assert!(
+            hint.contains("OpenAI-compat"),
+            "hint should identify the target provider: {hint}"
+        );
+        assert!(
+            hint.contains("openai/"),
+            "hint should mention the `openai/` prefix routing fix: {hint}"
+        );
+        assert!(
+            hint.contains("OPENAI_BASE_URL"),
+            "hint should mention OPENAI_BASE_URL so OpenRouter users see the full picture: {hint}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_hint_detects_xai_api_key() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", None);
+        let _xai = EnvVarGuard::set("XAI_API_KEY", Some("xai-test-key"));
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", None);
+
+        // when
+        let hint = anthropic_missing_credentials_hint()
+            .expect("XAI_API_KEY presence should produce a hint");
+
+        // then
+        assert!(
+            hint.contains("XAI_API_KEY is set"),
+            "hint should name XAI_API_KEY: {hint}"
+        );
+        assert!(
+            hint.contains("xAI"),
+            "hint should identify the xAI provider: {hint}"
+        );
+        assert!(
+            hint.contains("grok"),
+            "hint should suggest a grok-prefixed model alias: {hint}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_hint_detects_dashscope_api_key() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", None);
+        let _xai = EnvVarGuard::set("XAI_API_KEY", None);
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", Some("sk-dashscope-test"));
+
+        // when
+        let hint = anthropic_missing_credentials_hint()
+            .expect("DASHSCOPE_API_KEY presence should produce a hint");
+
+        // then
+        assert!(
+            hint.contains("DASHSCOPE_API_KEY is set"),
+            "hint should name DASHSCOPE_API_KEY: {hint}"
+        );
+        assert!(
+            hint.contains("DashScope"),
+            "hint should identify the DashScope provider: {hint}"
+        );
+        assert!(
+            hint.contains("qwen"),
+            "hint should suggest a qwen-prefixed model alias: {hint}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_hint_prefers_openai_when_multiple_foreign_creds_set() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", Some("sk-openrouter-varleg"));
+        let _xai = EnvVarGuard::set("XAI_API_KEY", Some("xai-test-key"));
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", Some("sk-dashscope-test"));
+
+        // when
+        let hint = anthropic_missing_credentials_hint()
+            .expect("multiple foreign creds should still produce a hint");
+
+        // then
+        assert!(
+            hint.contains("OPENAI_API_KEY"),
+            "OpenAI should be prioritized because it is the most common misrouting pattern (OpenRouter users), got: {hint}"
+        );
+        assert!(
+            !hint.contains("XAI_API_KEY"),
+            "only the first detected provider should be named to keep the hint focused, got: {hint}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_builds_error_with_canonical_env_vars_and_no_hint_when_clean() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", None);
+        let _xai = EnvVarGuard::set("XAI_API_KEY", None);
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", None);
+
+        // when
+        let error = anthropic_missing_credentials();
+
+        // then
+        match &error {
+            ApiError::MissingCredentials {
+                provider,
+                env_vars,
+                hint,
+            } => {
+                assert_eq!(*provider, "Anthropic");
+                assert_eq!(*env_vars, &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"]);
+                assert!(
+                    hint.is_none(),
+                    "clean environment should not generate a hint, got {hint:?}"
+                );
+            }
+            other => panic!("expected MissingCredentials variant, got {other:?}"),
+        }
+        let rendered = error.to_string();
+        assert!(
+            !rendered.contains(" — hint: "),
+            "rendered error should be a plain missing-creds message: {rendered}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_builds_error_with_hint_when_openai_key_is_set() {
+        // given
+        let _lock = env_lock();
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", Some("sk-openrouter-varleg"));
+        let _xai = EnvVarGuard::set("XAI_API_KEY", None);
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", None);
+
+        // when
+        let error = anthropic_missing_credentials();
+
+        // then
+        match &error {
+            ApiError::MissingCredentials {
+                provider,
+                env_vars,
+                hint,
+            } => {
+                assert_eq!(*provider, "Anthropic");
+                assert_eq!(*env_vars, &["ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_API_KEY"]);
+                let hint_value = hint.as_deref().expect("hint should be populated");
+                assert!(
+                    hint_value.contains("OPENAI_API_KEY is set"),
+                    "hint should name the detected env var: {hint_value}"
+                );
+            }
+            other => panic!("expected MissingCredentials variant, got {other:?}"),
+        }
+        let rendered = error.to_string();
+        assert!(
+            rendered.starts_with("missing Anthropic credentials;"),
+            "canonical base message should still lead the rendered error: {rendered}"
+        );
+        assert!(
+            rendered.contains(" — hint: I see OPENAI_API_KEY is set"),
+            "rendered error should carry the env-driven hint: {rendered}"
+        );
+    }
+
+    #[test]
+    fn anthropic_missing_credentials_hint_ignores_empty_string_values() {
+        // given
+        let _lock = env_lock();
+        // An empty value is semantically equivalent to "not set" for the
+        // credential discovery path, so the sniffer must treat it that way
+        // to avoid false-positive hints for users who intentionally cleared
+        // a stale export with `OPENAI_API_KEY=`.
+        let _openai = EnvVarGuard::set("OPENAI_API_KEY", Some(""));
+        let _xai = EnvVarGuard::set("XAI_API_KEY", None);
+        let _dashscope = EnvVarGuard::set("DASHSCOPE_API_KEY", None);
+
+        // when
+        let hint = anthropic_missing_credentials_hint();
+
+        // then
+        assert!(
+            hint.is_none(),
+            "empty env var should not trigger the hint sniffer, got {hint:?}"
+        );
+    }
 }

rust/crates/api/src/providers/openai_compat.rs

@@ -98,6 +98,11 @@ impl OpenAiCompatClient {
     const fn config(&self) -> OpenAiCompatConfig {
         self.config
     }
+
+    #[must_use]
+    pub fn base_url(&self) -> &str {
+        &self.base_url
+    }
     #[must_use]
     pub fn new(api_key: impl Into<String>, config: OpenAiCompatConfig) -> Self {
         Self {

rust/crates/api/tests/provider_client_integration.rs

@@ -22,7 +22,9 @@ fn provider_client_reports_missing_xai_credentials_for_grok_models() {
         .expect_err("grok requests without XAI_API_KEY should fail fast");
 
     match error {
-        ApiError::MissingCredentials { provider, env_vars } => {
+        ApiError::MissingCredentials {
+            provider, env_vars, ..
+        } => {
             assert_eq!(provider, "xAI");
             assert_eq!(env_vars, &["XAI_API_KEY"]);
         }

rust/crates/plugins/src/hooks.rs

@@ -337,7 +337,28 @@ impl CommandWithStdin {
         let mut child = self.command.spawn()?;
         if let Some(mut child_stdin) = child.stdin.take() {
             use std::io::Write as _;
-            child_stdin.write_all(stdin)?;
+            // Tolerate BrokenPipe: a hook script that runs to completion
+            // (or exits early without reading stdin) closes its stdin
+            // before the parent finishes writing the JSON payload, and
+            // the kernel raises EPIPE on the parent's write_all. That is
+            // not a hook failure — the child still exited cleanly and we
+            // still need to wait_with_output() to capture stdout/stderr
+            // and the real exit code. Other write errors (e.g. EIO,
+            // permission, OOM) still propagate.
+            //
+            // This was the root cause of the Linux CI flake on
+            // hooks::tests::collects_and_runs_hooks_from_enabled_plugins
+            // (ROADMAP #25, runs 24120271422 / 24120538408 / 24121392171
+            // / 24121776826): the test hook scripts run in microseconds
+            // and the parent's stdin write races against child exit.
+            // macOS pipes happen to buffer the small payload before the
+            // child exits; Linux pipes do not, so the race shows up
+            // deterministically on ubuntu runners.
+            match child_stdin.write_all(stdin) {
+                Ok(()) => {}
+                Err(error) if error.kind() == std::io::ErrorKind::BrokenPipe => {}
+                Err(error) => return Err(error),
+            }
         }
         child.wait_with_output()
     }
@@ -359,6 +380,18 @@ mod tests {
         std::env::temp_dir().join(format!("plugins-hook-runner-{label}-{nanos}"))
     }
 
+    fn make_executable(path: &Path) {
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::PermissionsExt;
+            let perms = fs::Permissions::from_mode(0o755);
+            fs::set_permissions(path, perms)
+                .unwrap_or_else(|e| panic!("chmod +x {}: {e}", path.display()));
+        }
+        #[cfg(not(unix))]
+        let _ = path;
+    }
+
     fn write_hook_plugin(
         root: &Path,
         name: &str,
@@ -368,21 +401,30 @@ mod tests {
     ) {
         fs::create_dir_all(root.join(".claude-plugin")).expect("manifest dir");
         fs::create_dir_all(root.join("hooks")).expect("hooks dir");
+
+        let pre_path = root.join("hooks").join("pre.sh");
         fs::write(
-            root.join("hooks").join("pre.sh"),
+            &pre_path,
             format!("#!/bin/sh\nprintf '%s\\n' '{pre_message}'\n"),
         )
         .expect("write pre hook");
+        make_executable(&pre_path);
+
+        let post_path = root.join("hooks").join("post.sh");
         fs::write(
-            root.join("hooks").join("post.sh"),
+            &post_path,
             format!("#!/bin/sh\nprintf '%s\\n' '{post_message}'\n"),
         )
         .expect("write post hook");
+        make_executable(&post_path);
+
+        let failure_path = root.join("hooks").join("failure.sh");
         fs::write(
-            root.join("hooks").join("failure.sh"),
+            &failure_path,
             format!("#!/bin/sh\nprintf '%s\\n' '{failure_message}'\n"),
         )
         .expect("write failure hook");
+        make_executable(&failure_path);
         fs::write(
             root.join(".claude-plugin").join("plugin.json"),
             format!(
@@ -496,4 +538,66 @@ mod tests {
             .iter()
             .any(|message| message == "later plugin hook"));
     }
+
+    #[test]
+    #[cfg(unix)]
+    fn generated_hook_scripts_are_executable() {
+        use std::os::unix::fs::PermissionsExt;
+
+        // given
+        let root = temp_dir("exec-guard");
+        write_hook_plugin(&root, "exec-check", "pre", "post", "fail");
+
+        // then
+        for script in ["pre.sh", "post.sh", "failure.sh"] {
+            let path = root.join("hooks").join(script);
+            let mode = fs::metadata(&path)
+                .unwrap_or_else(|e| panic!("{script} metadata: {e}"))
+                .permissions()
+                .mode();
+            assert!(
+                mode & 0o111 != 0,
+                "{script} must have at least one execute bit set, got mode {mode:#o}"
+            );
+        }
+    }
+
+    #[test]
+    fn output_with_stdin_tolerates_broken_pipe_when_child_closes_stdin_early() {
+        // given: a hook that immediately closes stdin without consuming the
+        // JSON payload. Use an oversized payload so the parent keeps writing
+        // long enough for Linux to surface EPIPE on the old implementation.
+        let root = temp_dir("stdin-close");
+        let script = root.join("close-stdin.sh");
+        fs::create_dir_all(&root).expect("temp hook dir");
+        fs::write(
+            &script,
+            "#!/bin/sh\nexec 0<&-\nprintf 'stdin closed early\\n'\nsleep 0.05\n",
+        )
+        .expect("write stdin-closing hook");
+        make_executable(&script);
+
+        let mut child = super::shell_command(script.to_str().expect("utf8 path"));
+        child.stdin(std::process::Stdio::piped());
+        child.stdout(std::process::Stdio::piped());
+        child.stderr(std::process::Stdio::piped());
+        let large_input = vec![b'x'; 2 * 1024 * 1024];
+
+        // when
+        let output = child
+            .output_with_stdin(&large_input)
+            .expect("broken pipe should be tolerated");
+
+        // then
+        assert!(
+            output.status.success(),
+            "child should still exit cleanly: {output:?}"
+        );
+        assert_eq!(
+            String::from_utf8_lossy(&output.stdout).trim(),
+            "stdin closed early"
+        );
+
+        let _ = fs::remove_dir_all(root);
+    }
 }

rust/crates/rusty-claude-cli/build.rs

@@ -0,0 +1,59 @@
+use std::env;
+use std::process::Command;
+
+fn main() {
+    // Get git SHA (short hash)
+    let git_sha = Command::new("git")
+        .args(["rev-parse", "--short", "HEAD"])
+        .output()
+        .ok()
+        .and_then(|output| {
+            if output.status.success() {
+                String::from_utf8(output.stdout).ok()
+            } else {
+                None
+            }
+        })
+        .map(|s| s.trim().to_string())
+        .unwrap_or_else(|| "unknown".to_string());
+
+    println!("cargo:rustc-env=GIT_SHA={}", git_sha);
+
+    // TARGET is always set by Cargo during build
+    let target = env::var("TARGET").unwrap_or_else(|_| "unknown".to_string());
+    println!("cargo:rustc-env=TARGET={}", target);
+
+    // Build date from SOURCE_DATE_EPOCH (reproducible builds) or current UTC date.
+    // Intentionally ignoring time component to keep output deterministic within a day.
+    let build_date = std::env::var("SOURCE_DATE_EPOCH")
+        .ok()
+        .and_then(|epoch| epoch.parse::<i64>().ok())
+        .map(|_ts| {
+            // Use SOURCE_DATE_EPOCH to derive date via chrono if available;
+            // for simplicity we just use the env var as a signal and fall back
+            // to build-time env. In practice CI sets this via workflow.
+            std::env::var("BUILD_DATE").unwrap_or_else(|_| "unknown".to_string())
+        })
+        .or_else(|| std::env::var("BUILD_DATE").ok())
+        .unwrap_or_else(|| {
+            // Fall back to current date via `date` command
+            Command::new("date")
+                .args(["+%Y-%m-%d"])
+                .output()
+                .ok()
+                .and_then(|o| {
+                    if o.status.success() {
+                        String::from_utf8(o.stdout).ok()
+                    } else {
+                        None
+                    }
+                })
+                .map(|s| s.trim().to_string())
+                .unwrap_or_else(|| "unknown".to_string())
+        });
+    println!("cargo:rustc-env=BUILD_DATE={build_date}");
+
+    // Rerun if git state changes
+    println!("cargo:rerun-if-changed=.git/HEAD");
+    println!("cargo:rerun-if-changed=.git/refs");
+}

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

@@ -26,8 +26,9 @@ use std::time::{Duration, Instant, UNIX_EPOCH};
 use api::{
     detect_provider_kind, oauth_token_is_expired, resolve_startup_auth_source, AnthropicClient,
     AuthSource, ContentBlockDelta, InputContentBlock, InputMessage, MessageRequest,
-    MessageResponse, OutputContentBlock, PromptCache, ProviderKind, StreamEvent as ApiStreamEvent,
-    ToolChoice, ToolDefinition, ToolResultContentBlock,
+    MessageResponse, OutputContentBlock, PromptCache, ProviderClient as ApiProviderClient,
+    ProviderKind, StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition,
+    ToolResultContentBlock,
 };
 
 use commands::{
@@ -66,7 +67,12 @@ fn max_tokens_for_model(model: &str) -> u32 {
         64_000
     }
 }
-const DEFAULT_DATE: &str = "2026-03-31";
+// Build-time constants injected by build.rs (fall back to static values when
+// build.rs hasn't run, e.g. in doc-test or unusual toolchain environments).
+const DEFAULT_DATE: &str = match option_env!("BUILD_DATE") {
+    Some(d) => d,
+    None => "unknown",
+};
 const DEFAULT_OAUTH_CALLBACK_PORT: u16 = 4545;
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 const BUILD_TARGET: Option<&str> = option_env!("TARGET");
@@ -6348,9 +6354,15 @@ impl runtime::PermissionPrompter for CliPermissionPrompter {
     }
 }
 
+// NOTE: Despite the historical name `AnthropicRuntimeClient`, this struct
+// now holds an `ApiProviderClient` which dispatches to Anthropic, xAI,
+// OpenAI, or DashScope at construction time based on
+// `detect_provider_kind(&model)`. The struct name is kept to avoid
+// churning `BuiltRuntime` and every Deref/DerefMut site that references
+// it. See ROADMAP #29 for the provider-dispatch routing fix.
 struct AnthropicRuntimeClient {
     runtime: tokio::runtime::Runtime,
-    client: AnthropicClient,
+    client: ApiProviderClient,
     session_id: String,
     model: String,
     enable_tools: bool,
@@ -6370,11 +6382,51 @@ impl AnthropicRuntimeClient {
         tool_registry: GlobalToolRegistry,
         progress_reporter: Option<InternalPromptProgressReporter>,
     ) -> Result<Self, Box<dyn std::error::Error>> {
+        // Dispatch to the correct provider at construction time.
+        // `ApiProviderClient` (exposed by the api crate as
+        // `ProviderClient`) is an enum over Anthropic / xAI / OpenAI
+        // variants, where xAI and OpenAI both use the OpenAI-compat
+        // wire format under the hood. We consult
+        // `detect_provider_kind(&resolved_model)` so model-name prefix
+        // routing (`openai/`, `gpt-`, `grok`, `qwen/`) wins over
+        // env-var presence.
+        //
+        // For Anthropic we build the client directly instead of going
+        // through `ApiProviderClient::from_model_with_anthropic_auth`
+        // so we can explicitly apply `api::read_base_url()` — that
+        // reads `ANTHROPIC_BASE_URL` and is required for the local
+        // mock-server test harness
+        // (`crates/rusty-claude-cli/tests/compact_output.rs`) to point
+        // claw at its fake Anthropic endpoint. We also attach a
+        // session-scoped prompt cache on the Anthropic path; the
+        // prompt cache is Anthropic-only so non-Anthropic variants
+        // skip it.
+        let resolved_model = api::resolve_model_alias(&model);
+        let client = match detect_provider_kind(&resolved_model) {
+            ProviderKind::Anthropic => {
+                let auth = resolve_cli_auth_source()?;
+                let inner = AnthropicClient::from_auth(auth)
+                    .with_base_url(api::read_base_url())
+                    .with_prompt_cache(PromptCache::new(session_id));
+                ApiProviderClient::Anthropic(inner)
+            }
+            ProviderKind::Xai | ProviderKind::OpenAi => {
+                // The api crate's `ProviderClient::from_model_with_anthropic_auth`
+                // with `None` for the anthropic auth routes via
+                // `detect_provider_kind` and builds an
+                // `OpenAiCompatClient::from_env` with the matching
+                // `OpenAiCompatConfig` (openai / xai / dashscope).
+                // That reads the correct API-key env var and BASE_URL
+                // override internally, so this one call covers OpenAI,
+                // OpenRouter, xAI, DashScope, Ollama, and any other
+                // OpenAI-compat endpoint users configure via
+                // `OPENAI_BASE_URL` / `XAI_BASE_URL` / `DASHSCOPE_BASE_URL`.
+                ApiProviderClient::from_model_with_anthropic_auth(&resolved_model, None)?
+            }
+        };
         Ok(Self {
             runtime: tokio::runtime::Runtime::new()?,
-            client: AnthropicClient::from_auth(resolve_cli_auth_source()?)
-                .with_base_url(api::read_base_url())
-                .with_prompt_cache(PromptCache::new(session_id)),
+            client,
             session_id: session_id.to_string(),
             model,
             enable_tools,
@@ -7404,7 +7456,12 @@ fn response_to_events(
     Ok(events)
 }
 
-fn push_prompt_cache_record(client: &AnthropicClient, events: &mut Vec<AssistantEvent>) {
+fn push_prompt_cache_record(client: &ApiProviderClient, events: &mut Vec<AssistantEvent>) {
+    // `ApiProviderClient::take_last_prompt_cache_record` is a pass-through
+    // to the Anthropic variant and returns `None` for OpenAI-compat /
+    // xAI variants, which do not have a prompt cache. So this helper
+    // remains a no-op on non-Anthropic providers without any extra
+    // branching here.
     if let Some(record) = client.take_last_prompt_cache_record() {
         if let Some(event) = prompt_cache_record_to_runtime_event(record) {
             events.push(AssistantEvent::PromptCache(event));

rust/crates/tools/src/lib.rs

@@ -6249,6 +6249,14 @@ mod tests {
 
     #[test]
     fn web_search_extracts_and_filters_results() {
+        // Serialize env-var mutation so this test cannot race with the sibling
+        // web_search_handles_generic_links_and_invalid_base_url test that also
+        // sets CLAWD_WEB_SEARCH_BASE_URL. Without the lock, parallel test
+        // runners can interleave the set/remove calls and cause assertion
+        // failures on the wrong port.
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
         let server = TestServer::spawn(Arc::new(|request_line: &str| {
             assert!(request_line.contains("GET /search?q=rust+web+search "));
             HttpResponse::html(