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 of behavioral disclosure. It states the tool retrieves historical rating data but doesn't describe output format (e.g., time-series data, JSON structure), rate limits, error handling (e.g., for invalid usernames), or data freshness. For a read-only tool with zero annotation coverage, this leaves significant gaps in understanding how it behaves.

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 a single, efficient sentence that front-loads the core purpose without unnecessary details. Every word contributes to understanding the tool's function, making it appropriately sized and well-structured for quick comprehension.

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 (one parameter, no output schema, no annotations), the description is minimally complete but has gaps. It covers what the tool does but lacks details on output behavior, error cases, and usage context. For a simple read operation, this is adequate but not fully informative, aligning with a baseline score.

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 documented as 'Lichess username'. The description adds no additional semantic context beyond this, such as format requirements (e.g., case sensitivity) or examples. With high schema coverage, the baseline score of 3 is appropriate, as the description doesn't compensate but doesn't need to heavily.

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 tool's purpose: 'Get the chess rating history over time for a Lichess player across all time controls'. It specifies the verb ('Get'), resource ('rating history'), and scope ('all time controls'). However, it doesn't explicitly differentiate from sibling tools like 'lichess_get_user' or 'lichess_get_leaderboard', which might also provide rating-related data, preventing a perfect score.

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?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., whether the username must exist), exclusions, or comparisons to siblings like 'lichess_get_user' (which might include current ratings) or 'lichess_get_leaderboard' (which focuses on rankings). Usage is implied by the purpose but lacks explicit context.

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