lingtai-wechat 0.1.2

LingTai WeChat MCP server

lingtai-wechat

LingTai WeChat MCP server — iLink Bot API client with QR-code login, multi-modal messaging, and LICC inbox callback.

This is the canonical setup, configuration, and troubleshooting doc for the lingtai-wechat MCP. It is fetched by LingTai agents (or anyone else) when they need to install or configure this server.

MCP / LICC contract spec: see the lingtai-anatomy skill, reference/mcp-protocol.md, for the canonical specification of the catalog → registry → activation chain, environment-variable injection, and the LICC v1 inbox callback protocol. The reference client implementation is src/lingtai_wechat/licc.py in this repo (vendored verbatim into all first-party LingTai MCP repos — copy it if you're writing your own).

Tools

One omnibus MCP tool: wechat(action=...). Actions: send, check, read, reply, search, contacts, add_contact, remove_contact. Supports text, images, voice, video, and files (auto-detected from media_path extension).

Inbound messages (LICC)

Inbound WeChat messages flow into the host agent's inbox via the LingTai Inbox Callback Contract. Each new message is delivered as a LICC event with:

• from — contact alias (or raw wxid_... if no contact saved).
• subject — "wechat message from <name>".
• body — a ~300 char preview, including bracketed media references like [Image: /path], [Voice: /path], [Video: /path].
• metadata.message_id — for reply.
• metadata.from_user_id — raw wxid_....
• metadata.item_types — list of message item types (text, image, voice, video, file).

Session expiry events are also delivered via LICC with metadata.event_type: "session_expired" so the agent knows to ask for re-login.

Install

# Into the LingTai agent's venv (typically ~/.lingtai-tui/runtime/venv/)
pip install git+https://github.com/Lingtai-AI/lingtai-wechat.git

After install, python -m lingtai_wechat (or the lingtai-wechat script) starts the MCP server over stdio.

QR-code login (one-time, before first use)

WeChat doesn't issue static bot tokens. Authenticate by scanning a QR code with the WeChat mobile app.

⚠ The login QR is admin-only — do not share it. Scanning it logs a WeChat account in as the bot's backend identity. If a friend or end user scans it instead of you, their account binds in place of yours and your credentials are replaced. This is not a contact / group / customer-service QR — those are shared from inside WeChat after login, and are how users actually chat with the bot.

Recommended: browser bootstrap

lingtai-wechat-bootstrap .secrets/wechat

This is the preferred first-time setup. It:

1. Creates .secrets/wechat/config.json with defaults if missing.
2. Renders the QR as an SVG inside a self-contained HTML page (with an admin-only warning banner) and opens it in your default browser.
3. Polls iLink for confirmation, auto-refreshing the QR if it expires.
4. Writes credentials.json (chmod 600) and tells you to refresh the MCP.

The page auto-refreshes every 3s and prints a clear admin-only warning so the scanner cannot mistake it for a chat QR.

Headless fallback: terminal QR

If the host has no browser or you're connecting over SSH without X-forwarding:

python -c "from lingtai_wechat.login import cli_login; cli_login('.secrets/wechat')"

This prints an ASCII QR directly to the terminal. Scan it with WeChat. On success, credentials.json is written into the directory you passed.

After login

credentials.json contains bot_token, user_id, and base_url. Sessions expire periodically (typically ~30 days). When expired, you'll see a LICC event with metadata.event_type: "session_expired" — re-run the bootstrap.

Configure

The server reads two files from the directory pointed at by LINGTAI_WECHAT_CONFIG:

• config.json — user-controlled options.
• credentials.json — written by lingtai-wechat-bootstrap (or the cli_login fallback). Don't edit by hand.

config.json schema

{
  "poll_interval": 1.0,
  "allowed_users": ["wxid_abc123"],
  "cdn_base_url": "https://..."
}

• poll_interval — seconds between iLink long-polls (default 1.0).
• allowed_users — optional allow-list of WeChat user IDs. When set, messages from other senders are silently ignored. Omit to accept any sender.
• cdn_base_url — usually omit; the default works.

Activation in LingTai

{
  "addons": ["wechat"],
  "mcp": {
    "wechat": {
      "type": "stdio",
      "command": "/path/to/your/python",
      "args": ["-m", "lingtai_wechat"],
      "env": {
        "LINGTAI_WECHAT_CONFIG": ".secrets/wechat/config.json"
      }
    }
  }
}

Then run system(action="refresh") from the agent. The MCP subprocess starts, the iLink long-poll begins, and the omnibus wechat tool becomes available.

Troubleshooting

• LINGTAI_WECHAT_CONFIG env var not set — your init.json mcp.wechat.env entry is missing the LINGTAI_WECHAT_CONFIG key.
• WeChat config not found — the path resolves but no file exists. Relative paths are resolved against LINGTAI_AGENT_DIR.
• WeChat credentials not found — config exists but credentials.json doesn't. Run the QR-code login flow above.
• WeChat session expired event in agent inbox — re-run the QR-code login flow.
• All connection attempts failed in stderr — usually a stale base_url in credentials. Re-run login.
• MCP server failed to start — usually the command path in init.json doesn't have lingtai_wechat installed. Confirm with <command> -m lingtai_wechat --help from a shell.
• Tool calls return WeChat manager not initialized — server boot failed (missing config or expired creds). Check stderr.

Multiple pollers after upgrading

iLink's getUpdates is a single-consumer long-poll: two processes holding the same bot_token race over inbound messages and each one gets a different subset. To prevent this, every lingtai-wechat poller takes an exclusive fcntl.flock on ~/.lingtai-wechat/locks/poller-<sha256(bot_token)[:16]>.lock at startup. If a second poller starts for the same account, it refuses with a PollerLockBusy error that includes the holder's PID.

After upgrading to a lingtai-wechat version with the lock, the new process may refuse to start because a pre-upgrade poller from another LingTai project is still running. Diagnose and stop it:

# 1. Find every lingtai_wechat poller currently running.
pgrep -af 'python.*lingtai_wechat'

# 2. The PollerLockBusy error names the holder PID. Inspect it:
ps -p <pid> -o pid,command
lsof -p <pid> 2>/dev/null | grep cwd   # which working dir launched it

# 3. Stop the old poller (refresh that project's MCP after).
kill -TERM <pid>

Notes:

• Lockfiles in ~/.lingtai-wechat/locks/ are intentionally left on disk after process exit — the flock kernel state is what's authoritative, not the file's presence. A leftover lockfile from a dead process is harmless; a new poller will reacquire the lock cleanly.
• The lock is keyed on sha256(bot_token), so two accounts produce different lockfiles and don't conflict. Multiple LingTai projects sharing one account is the case the lock prevents.
• On Windows, fcntl is unavailable; lingtai-wechat will refuse to start with UnsupportedPlatformError rather than silently re-introducing the race.

License

MIT.