diffler-mcp

A tiny stdio↔HTTP bridge that lets Claude Code (or any stdio MCP client) talk to the MCP server embedded in a running diffler review session.

diffler's MCP server runs inside the TUI as a streamable-HTTP endpoint (http://127.0.0.1:8417/mcp by default) because it serves the live review state on the app's main loop. This proxy is spawned by Claude over stdio and forwards every tool call to that endpoint — it owns no state itself.

Use it with Claude Code

Run diffler in your repo (it prints the connect hint and writes .diffler/mcp.json with the live port), then:

claude mcp add diffler -- npx -y diffler-mcp

Or in a checked-in .mcp.json:

{
  "mcpServers": {
    "diffler": {
      "command": "npx",
      "args": ["-y", "diffler-mcp"]
    }
  }
}

Run Claude from the repo root and the proxy auto-discovers the port from .diffler/mcp.json. No diffler running ⇒ the proxy exits with a clear error.

Configuration

Resolution order (first match wins):

1. --url <url> / DIFFLER_MCP_URL — full endpoint, e.g. http://127.0.0.1:8417/mcp
2. --port <n> / DIFFLER_MCP_PORT and --host <h> / DIFFLER_MCP_HOST
3. the live port in <repo>/.diffler/mcp.json (--repo <path>, default: cwd)
4. http://127.0.0.1:8417/mcp

{
  "mcpServers": {
    "diffler": {
      "command": "npx",
      "args": ["-y", "diffler-mcp", "--port", "8417"],
      "env": { "DIFFLER_MCP_HOST": "127.0.0.1" }
    }
  }
}

Prefer HTTP directly?

Claude Code speaks HTTP natively, so you can skip this proxy entirely:

claude mcp add --transport http diffler http://127.0.0.1:8417/mcp

The proxy exists for the npx, zero-config, auto-port-discovery ergonomics.