lichess_accept_challenge · Lichess MCP: Risk & Policy

WHAT IT DOES

What lichess_accept_challenge does on Lichess MCP

AI agents invoke lichess_accept_challenge to trigger actions in Lichess MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why lichess_accept_challenge needs a policy

This tool executes an action with external effects: accepting a challenge initiates a binding game on Lichess that involves time commitment, rating changes, and game records. While not destructive or financial, it is an execute-class tool because it performs a state-changing operation on a remote system whose consequences (game outcome affecting user rating/statistics) depend on subsequent AI moves.

From the tool's definition Tool description states 'Accept an incoming chess challenge' and 'Start the game' — this triggers real-time game state changes on the remote Lichess platform and commits the user to an active game session.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lichess_accept_challenge Rate-limited

lichess_accept_challenge stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "lichess_accept_challenge": {
      "limits": [
        {
          "counter": "lichess_accept_challenge_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Lichess MCP, so you can run agents against it safely.

FAQ

Questions about lichess_accept_challenge

What does the lichess_accept_challenge tool do? +

Accept an incoming chess challenge on Lichess. Start the game with the challenger. It is categorised as a Execute tool in the Lichess MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on lichess_accept_challenge? +

Register the Lichess MCP server in PolicyLayer and add a rule for lichess_accept_challenge: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Lichess MCP. Nothing to install.

What risk level is lichess_accept_challenge? +

lichess_accept_challenge is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit lichess_accept_challenge? +

Yes. Add a rate_limit block to the lichess_accept_challenge rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block lichess_accept_challenge completely? +

Set action: deny in the PolicyLayer policy for lichess_accept_challenge. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides lichess_accept_challenge? +

lichess_accept_challenge is provided by the Lichess MCP server (jamespdaily/lichess-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.