When stdin is not a terminal (pipe or redirect) and no prompt is given on the command line, claw was starting the interactive REPL and printing the startup banner, then consuming the pipe without sending anything to the API. Fix: in parse_args, when rest.is_empty() and stdin is not a terminal, read stdin synchronously and dispatch as CliAction::Prompt instead of Repl. Empty pipe still falls through to Repl (interactive launch with no input). Before: echo 'hello' | claw -> startup banner + REPL start After: echo 'hello' | claw -> dispatches as one-shot prompt 159 CLI tests pass, fmt clean.
🦞 Claw Code — Rust Implementation
A high-performance Rust rewrite of the Claw Code CLI agent harness. Built for speed, safety, and native tool execution.
For a task-oriented guide with copy/paste examples, see ../USAGE.md.
Quick Start
# Inspect available commands
cd rust/
cargo run -p rusty-claude-cli -- --help
# Build the workspace
cargo build --workspace
# Run the interactive REPL
cargo run -p rusty-claude-cli -- --model claude-opus-4-6
# One-shot prompt
cargo run -p rusty-claude-cli -- prompt "explain this codebase"
# JSON output for automation
cargo run -p rusty-claude-cli -- --output-format json prompt "summarize src/main.rs"
Configuration
Set your API credentials:
export ANTHROPIC_API_KEY="sk-ant-..."
# Or use a proxy
export ANTHROPIC_BASE_URL="https://your-proxy.com"
Or authenticate via OAuth and let the CLI persist credentials locally:
cargo run -p rusty-claude-cli -- login
Mock parity harness
The workspace now includes a deterministic Anthropic-compatible mock service and a clean-environment CLI harness for end-to-end parity checks.
cd rust/
# Run the scripted clean-environment harness
./scripts/run_mock_parity_harness.sh
# Or start the mock service manually for ad hoc CLI runs
cargo run -p mock-anthropic-service -- --bind 127.0.0.1:0
Harness coverage:
streaming_textread_file_roundtripgrep_chunk_assemblywrite_file_allowedwrite_file_deniedmulti_tool_turn_roundtripbash_stdout_roundtripbash_permission_prompt_approvedbash_permission_prompt_deniedplugin_tool_roundtrip
Primary artifacts:
crates/mock-anthropic-service/— reusable mock Anthropic-compatible servicecrates/rusty-claude-cli/tests/mock_parity_harness.rs— clean-env CLI harnessscripts/run_mock_parity_harness.sh— reproducible wrapperscripts/run_mock_parity_diff.py— scenario checklist + PARITY mapping runnermock_parity_scenarios.json— scenario-to-PARITY manifest
Features
| Feature | Status |
|---|---|
| Anthropic / OpenAI-compatible provider flows + streaming | ✅ |
| OAuth login/logout | ✅ |
| Interactive REPL (rustyline) | ✅ |
| Tool system (bash, read, write, edit, grep, glob) | ✅ |
| Web tools (search, fetch) | ✅ |
| Sub-agent / agent surfaces | ✅ |
| Todo tracking | ✅ |
| Notebook editing | ✅ |
| CLAUDE.md / project memory | ✅ |
Config file hierarchy (.claw.json + merged config sections) |
✅ |
| Permission system | ✅ |
| MCP server lifecycle + inspection | ✅ |
| Session persistence + resume | ✅ |
| Cost / usage / stats surfaces | ✅ |
| Git integration | ✅ |
| Markdown terminal rendering (ANSI) | ✅ |
| Model aliases (opus/sonnet/haiku) | ✅ |
Direct CLI subcommands (status, sandbox, agents, mcp, skills, doctor) |
✅ |
Slash commands (including /skills, /agents, /mcp, /doctor, /plugin, /subagent) |
✅ |
Hooks (/hooks, config-backed lifecycle hooks) |
✅ |
| Plugin management surfaces | ✅ |
| Skills inventory / install surfaces | ✅ |
| Machine-readable JSON output across core CLI surfaces | ✅ |
Model Aliases
Short names resolve to the latest model versions:
| Alias | Resolves To |
|---|---|
opus |
claude-opus-4-6 |
sonnet |
claude-sonnet-4-6 |
haiku |
claude-haiku-4-5-20251213 |
CLI Flags and Commands
Representative current surface:
claw [OPTIONS] [COMMAND]
Flags:
--model MODEL
--output-format text|json
--permission-mode MODE
--dangerously-skip-permissions
--allowedTools TOOLS
--resume [SESSION.jsonl|session-id|latest]
--version, -V
Top-level commands:
prompt <text>
help
version
status
sandbox
dump-manifests
bootstrap-plan
agents
mcp
skills
system-prompt
login
logout
init
The command surface is moving quickly. For the canonical live help text, run:
cargo run -p rusty-claude-cli -- --help
Slash Commands (REPL)
Tab completion expands slash commands, model aliases, permission modes, and recent session IDs.
The REPL now exposes a much broader surface than the original minimal shell:
- session / visibility:
/help,/status,/sandbox,/cost,/resume,/session,/version,/usage,/stats - workspace / git:
/compact,/clear,/config,/memory,/init,/diff,/commit,/pr,/issue,/export,/hooks,/files,/branch,/release-notes,/add-dir - discovery / debugging:
/mcp,/agents,/skills,/doctor,/tasks,/context,/desktop,/ide - automation / analysis:
/review,/advisor,/insights,/security-review,/subagent,/team,/telemetry,/providers,/cron, and more - plugin management:
/plugin(with aliases/plugins,/marketplace)
Notable claw-first surfaces now available directly in slash form:
/skills [list|install <path>|help]/agents [list|help]/mcp [list|show <server>|help]/doctor/plugin [list|install <path>|enable <name>|disable <name>|uninstall <id>|update <id>]/subagent [list|steer <target> <msg>|kill <id>]
See ../USAGE.md for usage examples and run cargo run -p rusty-claude-cli -- --help for the live canonical command list.
Workspace Layout
rust/
├── Cargo.toml # Workspace root
├── Cargo.lock
└── crates/
├── api/ # Provider clients + streaming + request preflight
├── commands/ # Shared slash-command registry + help rendering
├── compat-harness/ # TS manifest extraction harness
├── mock-anthropic-service/ # Deterministic local Anthropic-compatible mock
├── plugins/ # Plugin metadata, manager, install/enable/disable surfaces
├── runtime/ # Session, config, permissions, MCP, prompts, auth/runtime loop
├── rusty-claude-cli/ # Main CLI binary (`claw`)
├── telemetry/ # Session tracing and usage telemetry types
└── tools/ # Built-in tools, skill resolution, tool search, agent runtime surfaces
Crate Responsibilities
- api — provider clients, SSE streaming, request/response types, auth (API key + OAuth bearer), request-size/context-window preflight
- commands — slash command definitions, parsing, help text generation, JSON/text command rendering
- compat-harness — extracts tool/prompt manifests from upstream TS source
- mock-anthropic-service — deterministic
/v1/messagesmock for CLI parity tests and local harness runs - plugins — plugin metadata, install/enable/disable/update flows, plugin tool definitions, hook integration surfaces
- runtime —
ConversationRuntime, config loading, session persistence, permission policy, MCP client lifecycle, system prompt assembly, usage tracking - rusty-claude-cli — REPL, one-shot prompt, direct CLI subcommands, streaming display, tool call rendering, CLI argument parsing
- telemetry — session trace events and supporting telemetry payloads
- tools — tool specs + execution: Bash, ReadFile, WriteFile, EditFile, GlobSearch, GrepSearch, WebSearch, WebFetch, Agent, TodoWrite, NotebookEdit, Skill, ToolSearch, and runtime-facing tool discovery
Stats
- ~20K lines of Rust
- 9 crates in workspace
- Binary name:
claw - Default model:
claude-opus-4-6 - Default permissions:
danger-full-access
License
See repository root.