Lichess MCP

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It discloses the tool fetches public data, which is useful context, but doesn't mention behavioral traits like rate limits, error handling for invalid usernames, or response format. This leaves gaps in understanding how the tool behaves beyond its basic purpose.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core purpose in the first sentence and uses a second sentence to reinforce usage, with zero wasted words. Every sentence earns its place by clarifying the tool's scope and application efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's low complexity (single parameter, no output schema, no annotations), the description is adequate but incomplete. It covers the purpose and basic usage but lacks details on behavioral aspects like response structure or error cases, which would be helpful for an agent to use it correctly without annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% description coverage, with the 'username' parameter fully documented. The description adds no additional meaning beyond what the schema provides, such as format examples or constraints, so it meets the baseline of 3 for high schema coverage without compensating value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('Get'), resource ('Lichess user's public chess profile, ratings, and stats'), and target ('by username'), distinguishing it from siblings like lichess_get_my_profile (which fetches the authenticated user's data) and lichess_get_leaderboard (which retrieves rankings).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides clear context for when to use this tool ('Look up any player on Lichess'), implying it's for public user data. However, it lacks explicit exclusions or alternatives, such as not specifying when to use lichess_get_my_profile instead for authenticated users or lichess_get_crosstable for head-to-head stats.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.