@harnessa-fe/mcp-server

The MCP daemon for Harnessa-FE. Bridges AI agents (Claude, Cursor, Kiro) with running dev servers and browser tabs.

The MCP server exposes tools over stdio MCP to AI agents and runs a WebSocket bridge for the Vite/Webpack plugin and the browser runtime client. One daemon can serve multiple projects simultaneously.

Install

# Run on demand (recommended)
npx @harnessa-fe/mcp-server

# Or install globally
pnpm add -g @harnessa-fe/mcp-server
harnessa-fe

Use with Claude Code

Register the daemon as an MCP server in your Claude Code settings:

{
    "mcpServers": {
        "harnessa-fe": {
            "command": "npx",
            "args": ["-y", "@harnessa-fe/mcp-server"]
        }
    }
}

Cursor, Kiro, and other MCP-compatible clients use the same pattern.

LAN mode (real-device debugging)

The daemon binds 127.0.0.1 by default — local only, no auth needed.

To debug from a phone, tablet, or another machine on the same WiFi:

# Generate a one-shot token at startup
npx @harnessa-fe/mcp-server --host 0.0.0.0 --token auto

# Or reuse a stable token from your shell rc
export HARNESSA_FE_TOKEN=...
npx @harnessa-fe/mcp-server --host 0.0.0.0

The startup banner prints the dashboard URL with the token baked in — paste it into your phone's browser once and the daemon cookies the session.

Want a remote agent to share the daemon? Mount the MCP HTTP transport:

npx @harnessa-fe/mcp-server --host 0.0.0.0 --token auto \
  --mcp-transport http --mcp-path /mcp

Configure your remote Claude Code / Cursor:

{
  "type": "http",
  "url": "http://<lan-ip>:47729/mcp",
  "headers": { "Authorization": "Bearer <token>" }
}

Full guide: docs/lan-mode.md

All CLI flags

--host <addr>           Bind address (default 127.0.0.1; use 0.0.0.0 for LAN)
--port <number>         TCP port (default 47729)
--token <value|auto>    Required when --host is not loopback
--mcp-transport <kind>  stdio (default) | http
--mcp-path <path>       Default /mcp
--public-host <addr>    Override the host printed in outbound URLs
-h, --help

Matching env vars: HARNESSA_FE_HOST, HARNESSA_FE_TOKEN, HARNESSA_FE_MCP_TRANSPORT, HARNESSA_FE_MCP_PATH.

What it exposes

Tools across these domains (see Architecture):

• page — navigate, click, type, dom_query, evaluate, screenshot, …
• console / network / errors — tail and search runtime events
• session — list, replay, slice rrweb recordings
• project — source, where_is, module_graph (source-code intelligence)
• tasks — point-and-task annotation queue

Persistence lives in ~/.harnessa/ (JSONL event logs + JSON records).

Docs

• Root README
• Architecture

License

MIT