docs.acp.md

Hanzo Bot ACP Bridge

This document describes how the Hanzo Bot ACP (Agent Client Protocol) bridge works, how it maps ACP sessions to Gateway sessions, and how IDEs should invoke it.

Overview

hanzo-bot acp exposes an ACP agent over stdio and forwards prompts to a running Hanzo Bot Gateway over WebSocket. It keeps ACP session ids mapped to Gateway session keys so IDEs can reconnect to the same agent transcript or reset it on request.

Key goals:

• Minimal ACP surface area (stdio, NDJSON).
• Stable session mapping across reconnects.
• Works with existing Gateway session store (list/resolve/reset).
• Safe defaults (isolated ACP session keys by default).

How can I use this

Use ACP when an IDE or tooling speaks Agent Client Protocol and you want it to drive a Hanzo Bot Gateway session.

Quick steps:

1. Run a Gateway (local or remote).
2. Configure the Gateway target (gateway.remote.url + auth) or pass flags.
3. Point the IDE to run hanzo-bot acp over stdio.

Example config:

hanzo-bot config set gateway.remote.url wss://gateway-host:18789
hanzo-bot config set gateway.remote.token <token>

Example run:

hanzo-bot acp --url wss://gateway-host:18789 --token <token>

Selecting agents

ACP does not pick agents directly. It routes by the Gateway session key.

Use agent-scoped session keys to target a specific agent:

hanzo-bot acp --session agent:main:main
hanzo-bot acp --session agent:design:main
hanzo-bot acp --session agent:qa:bug-123

Each ACP session maps to a single Gateway session key. One agent can have many sessions; ACP defaults to an isolated acp:<uuid> session unless you override the key or label.

Zed editor setup

Add a custom ACP agent in ~/.config/zed/settings.json:

{
  "agent_servers": {
    "Hanzo Bot ACP": {
      "type": "custom",
      "command": "bot",
      "args": ["acp"],
      "env": {}
    }
  }
}

To target a specific Gateway or agent:

{
  "agent_servers": {
    "Hanzo Bot ACP": {
      "type": "custom",
      "command": "bot",
      "args": [
        "acp",
        "--url",
        "wss://gateway-host:18789",
        "--token",
        "<token>",
        "--session",
        "agent:design:main"
      ],
      "env": {}
    }
  }
}

In Zed, open the Agent panel and select “Hanzo Bot ACP” to start a thread.

Execution Model

• ACP client spawns hanzo-bot acp and speaks ACP messages over stdio.
• The bridge connects to the Gateway using existing auth config (or CLI flags).
• ACP prompt translates to Gateway chat.send.
• Gateway streaming events are translated back into ACP streaming events.
• ACP cancel maps to Gateway chat.abort for the active run.

Session Mapping

By default each ACP session is mapped to a dedicated Gateway session key:

• acp:<uuid> unless overridden.

You can override or reuse sessions in two ways:

1. CLI defaults

hanzo-bot acp --session agent:main:main
hanzo-bot acp --session-label "support inbox"
hanzo-bot acp --reset-session

2. ACP metadata per session

{
  "_meta": {
    "sessionKey": "agent:main:main",
    "sessionLabel": "support inbox",
    "resetSession": true,
    "requireExisting": false
  }
}

Rules:

• sessionKey: direct Gateway session key.
• sessionLabel: resolve an existing session by label.
• resetSession: mint a new transcript for the key before first use.
• requireExisting: fail if the key/label does not exist.

Session Listing

ACP listSessions maps to Gateway sessions.list and returns a filtered summary suitable for IDE session pickers. _meta.limit can cap the number of sessions returned.

Prompt Translation

ACP prompt inputs are converted into a Gateway chat.send:

• text and resource blocks become prompt text.
• resource_link with image mime types become attachments.
• The working directory can be prefixed into the prompt (default on, can be disabled with --no-prefix-cwd).

Gateway streaming events are translated into ACP message and tool_call updates. Terminal Gateway states map to ACP done with stop reasons:

• complete -> stop
• aborted -> cancel
• error -> error

Auth + Gateway Discovery

hanzo-bot acp resolves the Gateway URL and auth from CLI flags or config:

• --url / --token / --password take precedence.
• Otherwise use configured gateway.remote.* settings.

Operational Notes

• ACP sessions are stored in memory for the bridge process lifetime.
• Gateway session state is persisted by the Gateway itself.
• --verbose logs ACP/Gateway bridge events to stderr (never stdout).
• ACP runs can be canceled and the active run id is tracked per session.

Compatibility

• ACP bridge uses @agentclientprotocol/sdk (currently 0.13.x).
• Works with ACP clients that implement initialize, newSession, loadSession, prompt, cancel, and listSessions.

Testing

• Unit: src/acp/session.test.ts covers run id lifecycle.
• Full gate: pnpm build && pnpm check && pnpm test && pnpm docs:build.

Related Docs

• CLI usage: docs/cli/acp.md
• Session model: docs/concepts/session.md
• Session management internals: docs/reference/session-management-compaction.md