Codeforces MCP

Connect your AI assistant to your Codeforces account, so you can plan and review your practice just by asking.

Works with Claude Code, Codex, Claude.ai and any app that supports MCP.

Why I built this

Practicing on Codeforces means a lot of tab-switching: finding problems at the right rating, checking which ones you've already solved, looking up upcoming contests, reviewing your verdicts and rating history. I wanted to just ask instead:

• "Give me five DP problems rated around 1400 that I haven't tried."

• "Which of my recent submissions failed, and on what?"

• "When's the next Div. 2, and how did my last three contests go?"

This MCP server lets your AI assistant answer questions like these from live Codeforces data. It's built for practice — finding the right next problem and learning from your mistakes — not for solving problems for you, and never for rated contests.

What you can ask

💡 Tip: tell your assistant your handle once — "My Codeforces handle is tourist" — so it knows who "my" is. (Codeforces doesn't share which account a key belongs to.)

Related MCP server: mcp-codeforces

Server address

https://codeforces-mcp.rajaa-ai.co.in/mcp

Contents: For users · For developers

For users

1. Get a Codeforces API key

Open codeforces.com/settings/api → Add API key. Keep the Key and Secret handy.

2. Add the server to your app

For apps that use an mcpServers JSON file:

{ "mcpServers": { "codeforces": { "url": "https://codeforces-mcp.rajaa-ai.co.in/mcp" } } }

3. Log in

A browser page opens. Enter your API key and secret → Connect account. Done.

🔒 Only enter your key on that page — never paste it into a chat.

4. Ask away

Start with "My Codeforces handle is …", then try anything from What you can ask.

What it can do

🔑 = uses your logged-in account. Everything else works for any public handle.

Good to know

• Read-only — it can't submit solutions or change anything on your account.

• Your key stays private — encrypted on the server, never sent to the AI.

• Shared speed limit — about one Codeforces request every 2 seconds for everyone, so busy moments may say "try again shortly".

• Not for rated contests — Codeforces rules ban AI help during rated rounds.

Troubleshooting

To disconnect: remove the server from your app, then delete the key at codeforces.com/settings/api.

For developers

How it works

AI app ──MCP──▶ Cloudflare Worker ──signed API calls──▶ codeforces.com
                 │
                 ├─ OAuth login page (asks for your API key + secret)
                 ├─ KV: encrypted credentials and tokens
                 └─ Durable Object: one shared request queue (≈1 call / 2.1 s)

The AI app only ever receives an MCP access token. Your Codeforces key is encrypted at rest and used only by the server to sign requests.

Run locally (stdio)

Needs Node.js 22.15+.

git clone https://github.com/rajaaiitd/codeforces-mcp.git
cd codeforces-mcp && npm ci
npm run smoke        # starts the server and lists its tools

Point your app at it (see mcp-config.example.json):

{ "mcpServers": { "codeforces": { "command": "node", "args": ["/full/path/to/codeforces-mcp/src/index.js"] } } }

Optional: set CODEFORCES_API_KEY and CODEFORCES_API_SECRET in the app's settings to unlock the 🔑 tools.

Deploy your own server

See DEPLOY.md — Cloudflare Workers, with automatic deploys on every push. Your own copy gets its own speed limit.

Commands

npm test         # unit, OAuth and MCP tests
npm run smoke    # stdio smoke check (add -- --live to call Codeforces)
npm run dev      # Cloudflare Worker locally on :8787
npm run deploy   # deploy to Cloudflare

Project layout

src/api.js            Codeforces request signing, throttling, caching
src/tools.js          Public tool schemas, filters, pagination
src/account-tools.js  Logged-in tools
src/server.js         MCP tool registration
src/index.js          Local stdio entry point
src/cloudflare/       Worker, OAuth login page, Durable Object
test/                 Tests

References: Codeforces API · MCP TypeScript SDK

License

MIT. Independent project, not affiliated with Codeforces.