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 Pi, OpenClaw ACP, Codex, Claude, and other ACP-compatible agents. 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 resumed or 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>
• Session export/import: move portable session archives between machines
• Local status checks: status reports running/idle/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
• Compare across agents: acpx compare pi openclaw codex 'fix the bug' runs the same one-shot prompt against multiple ACP-compatible agents and summarizes timing, token usage, permissions, and final output side by side
• Experimental flows: flow run <file> for TypeScript workflow modules over multiple prompts
• Runtime-owned flow actions: shell-backed action steps can prepare workspaces and other deterministic mechanics outside the agent turn
• Flow workspace isolation: acp nodes can target an explicit per-step cwd, so flows can keep agent work inside disposable worktrees

$ 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 Pi, OpenClaw, 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. For Pi or OpenClaw, use the reference URL below. For Codex-style skill
   installation, install the acpx skill so you have the full reference
   available:
   npx acpx@latest --skill install acpx --agent codex --scope user
   Use --agent claude for Claude Code. For another harness not listed by
   --skill install --help, use the reference URL below instead.

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 pi -> Pi Coding Agent: https://github.com/mariozechner/pi
• acpx openclaw -> OpenClaw ACP bridge: https://github.com/openclaw/openclaw
• acpx codex -> Codex CLI: https://codex.openai.com
• acpx claude -> Claude Code: https://claude.ai/code

Additional built-in agent docs live in agents/README.md.

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 auto                        # session/set_mode (adapter-defined mode id)
acpx codex set model 'gpt-5.2[high]'            # adapter-advertised model control
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 token 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

Main landing harness examples:

acpx pi 'review recent changes'
acpx openclaw exec 'summarize active session state' # built-in OpenClaw ACP bridge
acpx codex 'fix the failing typecheck'
acpx claude 'refactor auth middleware' # built-in claude agent

Additional supported harnesses and their specific notes are documented in agents/README.md.

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 --policy '{"escalate":["execute"],"defaultAction":"deny"}' --format json codex exec 'ask before shell'

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 flow run ./my-flow.ts --input-file ./flow-input.json
acpx --timeout 1800 flow run ./my-flow.ts
acpx --format quiet codex 'final recommendation only'
acpx --suppress-reads codex exec 'show tool activity without dumping file bodies'

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'

Flows

acpx flow run <file> executes a TypeScript flow module through the acpx/flows runtime and persists run state under ~/.acpx/flows/runs/.

Flows are for multi-step ACP work where one prompt is not enough:

• acp steps keep model-shaped work in ACP
• decision() and decisionEdge() wrap constrained-choice ACP branching without adding a new node type
• action steps handle deterministic mechanics like shell commands or GitHub calls
• compute steps do local routing or shaping
• checkpoint steps pause for something outside the runtime

The source tree includes flow examples under examples/flows/README.md:

• small examples such as echo, branch, shell, workdir, and two-turn
• a larger PR-triage example under examples/flows/pr-triage/README.md
• a replay viewer under examples/flows/replay-viewer/README.md for inspecting saved run bundles in the browser

Example runs:

acpx flow run ./my-flow.ts --input-file ./flow-input.json

acpx flow run examples/flows/branch.flow.ts \
  --input-json '{"task":"FIX: add a regression test for the reconnect bug"}'

acpx flow run examples/flows/pr-triage/pr-triage.flow.ts \
  --input-json '{"repo":"openclaw/acpx","prNumber":150}'

The PR-triage example is only an example workflow. It can comment on or close real GitHub PRs if you run it against a live repository.

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.

Use --mcp-config <path> to load only the mcpServers array from an external JSON file without writing a project config file. Relative paths resolve from --cwd.

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", "args": ["acp"] }
  },
  "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.

For ACP authenticate handshakes, use either config auth entries or explicit ACPX_AUTH_<METHOD_ID> environment variables such as ACPX_AUTH_OPENAI_API_KEY. Ambient provider env vars such as OPENAI_API_KEY are still passed through to child agents, but they do not trigger ACP auth-method selection on their own.

Output formats

```bash

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'