Closes the #161 follow-up gap identified in review: wall-clock timeout bounded caller-facing wait but did not cancel the underlying provider thread, which could silently mutate mutable_messages / transcript_store / permission_denials / total_usage after the caller had already observed stop_reason='timeout'. A ghost turn committed post-deadline would poison any session that got persisted afterwards. Stage A scope (this commit): runtime + engine layer cooperative cancel. Engine layer (src/query_engine.py): - submit_message now accepts cancel_event: threading.Event | None = None - Two safe checkpoints: 1. Entry (before max_turns / budget projection) — earliest possible return 2. Post-budget (after output synthesis, before mutation) — catches cancel that arrives while output was being computed - Both checkpoints return stop_reason='cancelled' with state UNCHANGED (mutable_messages, transcript_store, permission_denials, total_usage all preserved exactly as on entry) - cancel_event=None preserves legacy behaviour with zero overhead (no checkpoint checks at all) Runtime layer (src/runtime.py): - run_turn_loop creates one cancel_event per invocation when a deadline is in play (and None otherwise, preserving legacy fast path) - Passes the same event to every submit_message call across turns, so a late cancel on turn N-1 affects turn N - On timeout (either pre-call or mid-call), runtime explicitly calls cancel_event.set() before future.cancel() + synthesizing the timeout TurnResult. This upgrades #161's best-effort future.cancel() (which only cancels not-yet-started futures) to cooperative mid-flight cancel. Stop reason taxonomy after Stage A: 'completed' — turn committed, state mutated exactly once 'max_budget_reached' — overflow, state unchanged (#162) 'max_turns_reached' — capacity exceeded, state unchanged 'cancelled' — cancel_event observed, state unchanged (#164 Stage A) 'timeout' — synthesised by runtime, not engine (#161) The 'cancelled' vs 'timeout' split matters: - 'timeout' is the runtime's best-effort signal to the caller: deadline hit - 'cancelled' is the engine's confirmation: cancel was observed + honoured If the provider call wedges entirely (never reaches a checkpoint), the caller still sees 'timeout' and the thread is leaked — but any NEXT submit_message call on the same engine observes the event at entry and returns 'cancelled' immediately, preventing ghost-turn accumulation. This is the honest cooperative limit in Python threading land; true preemption requires async-native provider IO (future work, not Stage A). Tests (29 new tests, tests/test_submit_message_cancellation.py + tests/ test_run_turn_loop_cancellation.py): Engine-layer (12 tests): - TestCancellationBeforeCall (5): pre-set event returns 'cancelled' immediately; mutable_messages, transcript_store, usage, permission_denials all preserved - TestCancellationAfterBudgetCheck (1): cancel set mid-call (after projection, before commit) still honoured; output synthesised but state untouched - TestCancellationAfterCommit (2): post-commit cancel not observable (honest limit) BUT next call on same engine observes it + returns 'cancelled' - TestLegacyCallersUnchanged (3): cancel_event=None preserves #162 atomicity + max_turns contract with zero behaviour change - TestCancellationVsOtherStopReasons (2): cancel precedes max_turns check; cancel does not retroactively override a completed turn Runtime-layer (5 tests): - TestTimeoutPropagatesCancelEvent (3): submit_message receives a real Event object when deadline is set; None in legacy mode; timeout actually calls event.set() so in-flight threads observe at their next checkpoint - TestCancelEventSharedAcrossTurns (1): same event object passed to every turn (object identity check) — late cancel on turn N-1 must affect turn N Regression: 3 existing timeout test mocks updated to accept cancel_event kwarg (mocks that previously had signature (prompt, commands, tools, denials) now have (prompt, commands, tools, denials, cancel_event=None) since runtime passes cancel_event positionally on the timeout path). Full suite: 97 → 114 passing, zero regression. Closes ROADMAP #164 Stage A. What's explicitly NOT in Stage A: - Preemptive cancellation of wedged provider IO (requires asyncio-native provider path; larger refactor) - Timeout on the legacy unbounded run_turn_loop path (by design: legacy callers opt out of cancellation entirely) - CLI exposure of 'cancelled' as a distinct exit code (currently 'cancelled' maps to the same stop_reason != 'completed' break condition as others; CLI surface for cancel is a separate pinpoint if warranted)
Claw Code
ultraworkers/claw-code · Usage · Rust workspace · Parity · Roadmap · UltraWorkers Discord
Claw Code is the public Rust implementation of the claw CLI agent harness.
The canonical implementation lives in rust/, and the current source of truth for this repository is ultraworkers/claw-code.
Important
Start with
USAGE.mdfor build, auth, CLI, session, and parity-harness workflows. Makeclaw doctoryour first health check after building, userust/README.mdfor crate-level details, readPARITY.mdfor the current Rust-port checkpoint, and seedocs/container.mdfor the container-first workflow.ACP / Zed status:
claw-codedoes not ship an ACP/Zed daemon entrypoint yet. Runclaw acp(orclaw --acp) for the current status instead of guessing from source layout;claw acp serveis currently a discoverability alias only, and real ACP support remains tracked separately inROADMAP.md.
Current repository shape
rust/— canonical Rust workspace and theclawCLI binaryUSAGE.md— task-oriented usage guide for the current product surfacePARITY.md— Rust-port parity status and migration notesROADMAP.md— active roadmap and cleanup backlogPHILOSOPHY.md— project intent and system-design framingsrc/+tests/— companion Python/reference workspace and audit helpers; not the primary runtime surface
Quick start
Note
[!WARNING]
cargo install claw-codeinstalls the wrong thing. Theclaw-codecrate on crates.io is a deprecated stub that placesclaw-code-deprecated.exe— notclaw. Running it only prints"claw-code has been renamed to agent-code". Do not usecargo install claw-code. Either build from source (this repo) or install the upstream binary:cargo install agent-code # upstream binary — installs 'agent.exe' (Windows) / 'agent' (Unix), NOT 'agent-code'This repo (
ultraworkers/claw-code) is build-from-source only — follow the steps below.
# 1. Clone and build
git clone https://github.com/ultraworkers/claw-code
cd claw-code/rust
cargo build --workspace
# 2. Set your API key (Anthropic API key — not a Claude subscription)
export ANTHROPIC_API_KEY="sk-ant-..."
# 3. Verify everything is wired correctly
./target/debug/claw doctor
# 4. Run a prompt
./target/debug/claw prompt "say hello"
Note
Windows (PowerShell): the binary is
claw.exe, notclaw. Use.\target\debug\claw.exeor runcargo run -- prompt "say hello"to skip the path lookup.
Windows setup
PowerShell is a supported Windows path. Use whichever shell works for you. The common onboarding issues on Windows are:
- Install Rust first — download from https://rustup.rs/ and run the installer. Close and reopen your terminal when it finishes.
- Verify Rust is on PATH:
If this fails, reopen your terminal or run the PATH setup from the Rust installer output, then retry.cargo --version - Clone and build (works in PowerShell, Git Bash, or WSL):
git clone https://github.com/ultraworkers/claw-code cd claw-code/rust cargo build --workspace - Run (PowerShell — note
.exeand backslash):$env:ANTHROPIC_API_KEY = "sk-ant-..." .\target\debug\claw.exe prompt "say hello"
Git Bash / WSL are optional alternatives, not requirements. If you prefer bash-style paths (/c/Users/you/... instead of C:\Users\you\...), Git Bash (ships with Git for Windows) works well. In Git Bash, the MINGW64 prompt is expected and normal — not a broken install.
Post-build: locate the binary and verify
After running cargo build --workspace, the claw binary is built but not automatically installed to your system. Here's where to find it and how to verify the build succeeded.
Binary location
After cargo build --workspace in claw-code/rust/:
Debug build (default, faster compile):
- macOS/Linux:
rust/target/debug/claw - Windows:
rust/target/debug/claw.exe
Release build (optimized, slower compile):
- macOS/Linux:
rust/target/release/claw - Windows:
rust/target/release/claw.exe
If you ran cargo build without --release, the binary is in the debug/ folder.
Verify the build succeeded
Test the binary directly using its path:
# macOS/Linux (debug build)
./rust/target/debug/claw --help
./rust/target/debug/claw doctor
# Windows PowerShell (debug build)
.\rust\target\debug\claw.exe --help
.\rust\target\debug\claw.exe doctor
If these commands succeed, the build is working. claw doctor is your first health check — it validates your API key, model access, and tool configuration.
Optional: Add to PATH
If you want to run claw from any directory without the full path, choose one of these approaches:
Option 1: Symlink (macOS/Linux)
ln -s $(pwd)/rust/target/debug/claw /usr/local/bin/claw
Then reload your shell and test:
claw --help
Option 2: Use cargo install (all platforms)
Build and install to Cargo's default location (~/.cargo/bin/, which is usually on PATH):
# From the claw-code/rust/ directory
cargo install --path . --force
# Then from anywhere
claw --help
Option 3: Update shell profile (bash/zsh)
Add this line to ~/.bashrc or ~/.zshrc:
export PATH="$(pwd)/rust/target/debug:$PATH"
Reload your shell:
source ~/.bashrc # or source ~/.zshrc
claw --help
Troubleshooting
- "command not found: claw" — The binary is in
rust/target/debug/claw, but it's not on your PATH. Use the full path./rust/target/debug/clawor symlink/install as above. - "permission denied" — On macOS/Linux, you may need
chmod +x rust/target/debug/clawif the executable bit isn't set (rare). - Debug vs. release — If the build is slow, you're in debug mode (default). Add
--releasetocargo buildfor faster runtime, but the build itself will take 5–10 minutes.
Note
Auth: claw requires an API key (
ANTHROPIC_API_KEY,OPENAI_API_KEY, etc.) — Claude subscription login is not a supported auth path.
Run the workspace test suite after verifying the binary works:
cd rust
cargo test --workspace
Documentation map
USAGE.md— quick commands, auth, sessions, config, parity harnessrust/README.md— crate map, CLI surface, features, workspace layoutPARITY.md— parity status for the Rust portrust/MOCK_PARITY_HARNESS.md— deterministic mock-service harness detailsROADMAP.md— active roadmap and open cleanup workPHILOSOPHY.md— why the project exists and how it is operated
Ecosystem
Claw Code is built in the open alongside the broader UltraWorkers toolchain:
Ownership / affiliation disclaimer
- This repository does not claim ownership of the original Claude Code source material.
- This repository is not affiliated with, endorsed by, or maintained by Anthropic.
