acpx

⚠️ acpx is in alpha and the CLI/runtime interfaces are likely to change. Anything you build downstream of this might break until it stabilizes.

ACP coverage status: see ACP Spec Coverage Roadmap.

Your agents love acpx! 🤖❤️ They hate having to scrape characters from a PTY session 😤

acpx is a headless CLI client for the Agent Client Protocol (ACP), so AI agents and orchestrators can talk to coding agents over a structured protocol instead of PTY scraping.

One command surface for Codex, Claude, Gemini, OpenCode, Pi, or custom ACP servers. Built for agent-to-agent communication over the command line.

• Persistent sessions: multi-turn conversations that survive across invocations, scoped per repo
• Named sessions: run parallel workstreams in the same repo (-s backend, -s frontend)
• Prompt queueing: submit prompts while one is already running, they execute in order
• Cooperative cancel command: cancel sends ACP session/cancel via queue IPC without tearing down session state
• Soft-close lifecycle: close sessions without deleting history from disk
• Queue owner TTL: keep queue owners alive briefly for follow-up prompts (--ttl)
• Fire-and-forget: --no-wait queues a prompt and returns immediately
• Graceful cancel: Ctrl+C sends ACP session/cancel before force-kill fallback
• Session controls: set-mode and set <key> <value> for session/set_mode and session/set_config_option
• Crash reconnect: dead agent processes are detected and sessions are reloaded automatically
• Prompt from file/stdin: --file <path> or piped stdin for prompt content
• Config files: global + project JSON config with acpx config show|init
• Session inspect/history: sessions show and sessions history --limit <n>
• Local status checks: status reports running/dead/no-session, pid, uptime, last prompt
• Client methods: stable fs/* and terminal/* handlers with permission controls and cwd sandboxing
• Auth handshake: stable authenticate support via env/config credentials
• Structured output: typed ACP messages (thinking, tool calls, diffs) instead of ANSI scraping
• Any ACP agent: built-in registry + --agent escape hatch for custom servers
• One-shot mode: exec for stateless fire-and-forget tasks

$ acpx codex sessions new
$ acpx codex "find the flaky test and fix it"

[thinking] Investigating test suite for flaky failures

[tool] Run npm test -- --reporter=verbose (running)
[tool] Run npm test -- --reporter=verbose (completed)
  output:
    ✓ auth.login (0.8s)
    ✗ checkout.submit (timed out after 5000ms)
    ✓ cart.add (0.3s)

[thinking] Found it — checkout.submit has a race condition in the async setup

[tool] Edit src/checkout.test.ts (completed)
  output:
    Success. Updated 1 file.

[tool] Run npm test -- checkout.submit (completed)
  output:
    ✓ checkout.submit (0.4s)

Fixed: added `await` to the setup hook in checkout.submit. The test was
reading stale state from the previous run.

[done] end_turn

Quick setup — tell your agent about acpx

Copy the block below and paste it into your OpenClaw, Pi, Claude Code, or similar agent harness. It will install acpx, read the skill reference, and know how to use ACP for all future coding agent tasks.

I want you to use acpx to run coding agents over the Agent Client Protocol
(ACP) instead of scraping PTY sessions. Please do the following:

1. Install acpx globally (recommended) or use npx:
   npm install -g acpx@latest

   Or without installing:
   npx acpx@latest

2. Install the acpx skill so you have the full reference available:
   npx acpx@latest --skill install acpx

3. Read the acpx skill reference so you know every command, flag, and
   workflow pattern:
   https://raw.githubusercontent.com/openclaw/acpx/main/skills/acpx/SKILL.md

4. If you need the full CLI reference with all options and examples:
   https://raw.githubusercontent.com/openclaw/acpx/main/docs/CLI.md

From now on, when you need to delegate work to a coding agent, use acpx
instead of spawning raw terminal sessions. For example:
  npx acpx@latest codex "fix the failing tests"
  npx acpx@latest claude "refactor the auth module"
  npx acpx@latest codex exec "one-shot: summarize this repo"

Install

npm install -g acpx@latest

Or run without installing:

npx acpx@latest codex "fix the tests"

Session state lives in ~/.acpx/ either way. Global install is a little faster, but npx acpx@latest works fine.

Agent prerequisites

acpx auto-downloads ACP adapters with npx on first use. You do not need to install adapter packages manually.

The only prerequisite is the underlying coding agent you want to use:

• acpx codex -> Codex CLI: https://codex.openai.com
• acpx claude -> Claude Code: https://claude.ai/code
• acpx gemini -> Gemini CLI: https://github.com/google/gemini-cli
• acpx opencode -> OpenCode: https://opencode.ai
• acpx pi -> Pi Coding Agent: https://github.com/mariozechner/pi

Usage examples

acpx codex sessions new                        # create a session (explicit) for this project dir
acpx codex 'fix the tests'                     # implicit prompt (routes via directory-walk)
acpx codex prompt 'fix the tests'              # explicit prompt subcommand
echo 'fix flaky tests' | acpx codex            # prompt from stdin
acpx codex --file prompt.md                    # prompt from file
acpx codex --file - "extra context"            # explicit stdin + appended args
acpx codex --no-wait 'draft test migration plan' # enqueue without waiting if session is busy
acpx codex cancel                               # cooperative cancel of in-flight prompt
acpx codex set-mode plan                        # session/set_mode
acpx codex set approval_policy conservative     # session/set_config_option
acpx exec 'summarize this repo'                # default agent shortcut (codex)
acpx codex exec 'what does this repo do?'      # one-shot, no saved session

acpx codex sessions new --name api              # create named session
acpx codex -s api 'implement cursor pagination' # prompt in named session
acpx codex sessions new --name docs             # create another named session
acpx codex -s docs 'rewrite API docs'           # parallel work in another named session

acpx codex sessions              # list sessions for codex command
acpx codex sessions list         # explicit list
acpx codex sessions show         # inspect cwd session metadata
acpx codex sessions history      # show recent turn history
acpx codex sessions new          # create fresh cwd-scoped default session
acpx codex sessions new --name api # create fresh named session
acpx codex sessions ensure       # return existing scoped session or create one
acpx codex sessions ensure --name api # ensure named scoped session
acpx codex sessions close        # close cwd-scoped default session
acpx codex sessions close api    # close cwd-scoped named session
acpx codex status                # local process status for current session

acpx config show                 # show resolved config (global + project)
acpx config init                 # create ~/.acpx/config.json template

acpx claude 'refactor auth middleware' # built-in claude agent
acpx gemini 'add startup logging'      # built-in gemini agent

acpx my-agent 'review this patch'                      # unknown name -> raw command
acpx --agent './bin/dev-acp --profile ci' 'run checks' # --agent escape hatch

Practical scenarios

# Review a PR in a dedicated session and auto-approve permissions
acpx --cwd ~/repos/shop --approve-all codex -s pr-842 \
  'Review PR #842 for regressions and propose a minimal fix'

# Keep parallel streams for the same repo
acpx codex -s bugfix 'isolate flaky checkout test'
acpx codex -s release 'draft release notes from recent commits'

Global options in practice

acpx --approve-all codex 'apply the patch and run tests'
acpx --approve-reads codex 'inspect repo structure and suggest plan' # default mode
acpx --deny-all codex 'explain what you can do without tool access'
acpx --non-interactive-permissions fail codex 'fail instead of deny in non-TTY'

acpx --cwd ~/repos/backend codex 'review recent auth changes'
acpx --format text codex 'summarize your findings'
acpx --format json codex exec 'review changed files'
acpx --format json --json-strict codex exec 'machine-safe JSON only'
acpx --format quiet codex 'final recommendation only'

acpx --timeout 90 codex 'investigate intermittent test timeout'
acpx --ttl 30 codex 'keep queue owner alive for quick follow-ups'
acpx --verbose codex 'debug why adapter startup is failing'

Configuration files

acpx reads config in this order (later wins):

1. global: ~/.acpx/config.json
2. project: <cwd>/.acpxrc.json

CLI flags always win over config values.

Supported keys:

{
  "defaultAgent": "codex",
  "defaultPermissions": "approve-all",
  "nonInteractivePermissions": "deny",
  "authPolicy": "skip",
  "ttl": 300,
  "timeout": null,
  "format": "text",
  "agents": {
    "my-custom": { "command": "./bin/my-acp-server" }
  },
  "auth": {
    "my_auth_method_id": "credential-value"
  }
}

Use acpx config show to inspect the resolved result and acpx config init to create the global template.

Output formats

# text (default): human-readable stream with tool updates
acpx codex 'review this PR'

# json: NDJSON events, useful for automation
acpx --format json codex exec 'review this PR' \
  | jq -r 'select(.type=="tool_call") | [.status, .title] | @tsv'

# json-strict: suppresses non-JSON stderr output (requires --format json)
acpx --format json --json-strict codex exec 'review this PR'

# quiet: final assistant text only
acpx --format quiet codex 'give me a 3-line summary'

JSON events include a stable envelope for correlation:

{
  "eventVersion": 1,
  "sessionId": "abc123",
  "requestId": "req-42",
  "seq": 7,
  "stream": "prompt",
  "type": "tool_call"
}

Session-control JSON payloads (sessions new|ensure, status) may also include runtimeSessionId when the adapter exposes a provider-native session ID.

Built-in agents and custom servers

Built-ins:

Use --agent as an escape hatch for custom ACP servers:

acpx --agent ./my-custom-acp-server 'do something'

Session behavior

• Prompt commands require an existing saved session record (created via sessions new or sessions ensure).
• Prompts route by walking up from cwd (or --cwd) to the nearest git root (inclusive) and selecting the nearest active session matching (agent command, dir, optional name).
• If no git root is found, prompts only match an exact cwd session (no parent-directory walk).
• -s <name> selects a parallel named session during that directory walk.
• sessions new [--name <name>] creates a fresh session for that scope and soft-closes the prior one.
• sessions ensure [--name <name>] is idempotent: it returns an existing scoped session or creates one when missing.
• sessions close [name] soft-closes the session: queue owner/processes are terminated, record is kept with closed: true.
• Auto-resume for cwd scope skips sessions marked closed.
• Prompt submissions are queue-aware per session. If a prompt is already running, new prompts are queued and drained by the running acpx process.
• Queue owners use an idle TTL (default 300s). --ttl <seconds> overrides it; --ttl 0 keeps owners alive indefinitely.
• --no-wait submits to that queue and returns immediately.
• cancel sends cooperative session/cancel to the running queue owner process and returns success when no prompt is running (nothing to cancel).
• set-mode and set route through queue-owner IPC when active, otherwise they reconnect directly to apply session/set_mode and session/set_config_option.
• exec is always one-shot and does not reuse saved sessions.
• Session metadata is stored under ~/.acpx/sessions/.
• Each successful prompt appends lightweight turn history previews (role, timestamp, textPreview) to session metadata.
• Ctrl+C during a running turn sends ACP session/cancel and waits briefly for stopReason=cancelled before force-killing if needed.
• If a saved session pid is dead on the next prompt, acpx respawns the agent, attempts session/load, and transparently falls back to session/new if loading fails.

Full CLI reference

See docs/CLI.md.

License

MIT