lichess_user

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description adds valuable context beyond annotations: 'Auth: none needed' and the caveat that there is no single 'rating' field, but perfs.<timeControl>.rating. It does not duplicate annotation info, and no contradictions exist.

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 well-organized: a brief purpose statement, a detailed but justified return structure, a clear example, and a short auth note. Every sentence serves a purpose, and it is front-loaded with the core intent.

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?

For a simple single-parameter read-only tool, the description is thoroughly complete. It provides the entire return shape, a concrete example, an auth note, and an important caveat about accessing ratings. This compensates for the absence of an output schema and gives the agent everything needed to invoke and interpret the result.

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 schema already fully documents the 'username' parameter (required, case-insensitive, part of URL path). The description adds a concrete example ('thibault'), which helps the agent understand expected input beyond the schema description. This exceeds the baseline for high schema coverage.

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 identifies the tool as retrieving a single Lichess player's data: ratings per time control, games played, play time, and profile. The 'Returns:' section and example ('One player's profile and ratings') unambiguously define the purpose, and it is distinct from sibling tools like lichess_leaderboard or lichess_users_status.

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 implies usage via the example and the required 'username' parameter: use when you need a specific player's profile. It provides clear context (single-player lookup) but does not explicitly mention alternatives or when-not-to-use scenarios, which would earn a 5.

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