letmediff

letmediff is a review handoff tool for agent-driven coding sessions.

The CLI runs as an MCP server inside a local repository, captures the current worktree diff, and posts it to the web app. The web app renders the diff at a shareable URL and sends reviewer feedback back to the MCP client over server-sent events.

Workspace

This repository is a pnpm monorepo.

• packages/letmediff contains the letmediff MCP CLI.

• apps/letmediff.it contains the SvelteKit app that stores, renders, and streams diff feedback.

Requirements

• Node.js compatible with the package dependencies

• pnpm ^11.2.2

Install

pnpm install

Local Development

Run the app:

pnpm --filter letmediff.it dev

Run the MCP server against the local app by setting URL:

URL=http://localhost:5173 pnpm --filter letmediff exec letmediff

When used by an MCP-compatible agent, the server exposes tools to create named checkpoints, create a hosted diff URL, and wait for reviewer feedback.

How It Works

1. The MCP server snapshots the repository when it starts.

2. The agent can create named checkpoints while it works.

3. When a review URL is requested, the server sends the collected checkpoint diffs to the app.

4. The app renders /diff/[id] and keeps an /events/[id] SSE connection open.

5. Submitted feedback is streamed back to the MCP server so the agent can continue from the review notes.

Package READMEs

• CLI: packages/letmediff/README.md

• App: apps/letmediff.it/README.md