peer-agents-mcp

MCP server that lets other AI coding tools (Codex, Claude, Cursor, etc.) call the Grok CLI and Antigravity CLI as peer reviewers and collaborators.

What it does

This server wraps the local grok and agy (Antigravity) CLIs behind a clean Model Context Protocol (MCP) interface.

Any MCP-capable agent can now:

• Send code changes, plans, errors, or questions to Grok or Antigravity
• Receive structured peer feedback
• Run multi-turn review/debug/planning sessions with session memory
• Get independent opinions by running both CLIs on the same task

The primary agent (Codex, Claude, etc.) stays in control. It simply delegates specific tasks to these peers when it wants a second (or different) opinion.

Core idea

Instead of one model doing everything, your main coding agent can use Grok and Antigravity as peers:

• Grok for most coding work (reviews, planning, debugging, implementation critique)
• Antigravity for large context, general knowledge, or multimodal tasks

Smart routing happens automatically based on the type of request.

Available tools

Tool	Purpose	Routed to
peer_review_diff	Review a unified diff or patch	Grok (usually)
peer_plan	Create an implementation plan	Grok
peer_debug	Diagnose failures from logs/stack traces	Grok
peer_verify	Check test/build output for safety	Grok
peer_ask	General grounded Q&A	Antigravity
peer_debate	Independently compare Plan A vs Plan B	Grok
peer_turn	Continue a multi-turn peer session	Same peer
peer_compare	Low-level side-by-side call to both CLIs	Both

Additional session tools: peer_summarize, peer_transcript, peer_list_sessions, peer_reset, and peer_health.

All routed tools accept full file contents via the files parameter and diffs via diff. Never send summaries — send the actual content.

How other agents use it

Codex, Claude, or any other MCP client connects to this server over stdio. Once connected, the agent can call the peer tools exactly like any other tool.

Typical flow:

1. Your agent prepares a diff, error log, or task description.
2. It calls peer_review_diff, peer_plan, peer_debug, etc.
3. The server invokes the appropriate CLI(s) in headless mode.
4. The peer response comes back with a sessionId.
5. Your agent can follow up later with peer_turn using that sessionId.

This gives you persistent, contextual peer conversations without the primary agent having to manage CLI invocation itself.

Prerequisites

• Node.js ≥ 18
• The grok CLI (or set GROK_COMMAND)
• The agy CLI (Antigravity, or set ANTIGRAVITY_COMMAND)

Both CLIs must be authenticated and working on your machine.

Installation & usage

git clone https://github.com/Rakeen70210/peer-agents-mcp
cd peer-agents-mcp
npm install
npm run build

Run directly:

node dist/index.js

MCP client configuration

Add it to your client's MCP servers config (example for a typical stdio setup):

{
  "mcpServers": {
    "peer-agents": {
      "command": "node",
      "args": ["/absolute/path/to/peer-agents-mcp/dist/index.js"],
      "env": {
        "GROK_COMMAND": "/home/you/.grok/bin/grok",
        "ANTIGRAVITY_COMMAND": "/home/you/.local/bin/agy"
      }
    }
  }
}

Environment variables

• GROK_COMMAND — path to grok binary (default: grok)
• ANTIGRAVITY_COMMAND — path to agy binary (default: agy)
• GROK_ARGS / ANTIGRAVITY_ARGS — JSON array of extra CLI args
• PEER_AGENTS_STORAGE_DIR — where sessions are persisted (default: ~/.peer-agents/sessions)
• PEER_AGENTS_TURN_TIMEOUT_MS — per-turn timeout (default 120s for Grok, 300s for Antigravity)
• PEER_AGENTS_MAX_PROMPT_CHARS — safety limit on prompt size

Multi-turn peer sessions

Each routed call returns a sessionId. Use peer_turn to continue the conversation:

• Tell the peer what changed
• Attach new diffs or files
• Ask it to re-review or check your fixes

Sessions are persisted to disk, so they survive across restarts of the MCP server.

Design notes

• The server never modifies your repo itself — it only runs the CLIs you already have.
• User messages in session transcripts are labeled from the caller's perspective (commonly "Codex").
• Idempotency keys are supported so repeated calls with the same key are safe.
• Context quality hints are returned when the input looks too thin (missing files, diffs, etc.).

License

MIT (or as specified in the repo).