Gitsum reads a GitHub repository for you — what it is, how to run it, where things live — and answers with exact path:line evidence. In a Chrome side panel, in Claude Code, Cursor or any agent.
Free for individuals. No account, no API key.
Download the latest build, unzip, open chrome://extensions, turn on Developer mode and choose Load unpacked. Then click Gitsum on any repo.
Claude Code:
claude mcp add gitsum -- npx -y github:in-c0/gitsum mcp
Cursor / Claude Desktop / any client (mcp.json):
{ "mcpServers": { "gitsum": { "command": "npx", "args": ["-y", "github:in-c0/gitsum", "mcp"] } } }
Paste into any agent that can read a Skill and use a terminal:
Use this Skill: https://raw.githubusercontent.com/in-c0/gitsum/main/skills/gitsum/SKILL.md Explain how expressjs/express routes a request, with file:line citations.
Claude Code plugin (Skill + MCP together):
/plugin marketplace add in-c0/gitsum /plugin install gitsum@gitsum
We ask "Where is X defined?" for identifiers sampled from 10 popular repos (express, flask, requests, ky, axios, cobra, gin, ripgrep, zod, commander) and check the true file. Held-out seeds, 240 questions. Re-run it: npm run bench.
Individuals never pay. Companies pay for the hosted service their whole team shares.
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