chesscom_player

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

Annotations already mark the tool read-only, idempotent, and open-world. The description adds useful context beyond these: 'Auth: none needed' and critical format caveats (joined/last_online are UNIX seconds, country is a URL rather than a code). It also enumerates the exact return fields, which is helpful.

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-structured with labeled sections (Returns, Example, Auth) and every sentence contributes value. It is concise and front-loaded with the primary purpose, making it easy for an agent to parse quickly.

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 tool with one parameter and no output schema, the description covers the return shape, important field format nuances, an example, and auth requirements. It is sufficiently complete for correct selection and invocation, though it could optionally mention error behavior or data freshness.

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 documents the only parameter (username) with a clear description (lowercase, required, part of URL path). The description's example provides a concrete value but does not add significant semantic information beyond what the schema already states. With 100% schema coverage, the baseline of 3 applies.

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 returning a Chess.com player's profile and lists key fields, distinguishing it from siblings like chesscom_player_stats. However, it lacks an explicit verb like 'Get' or 'Fetch', relying on the noun phrase and the 'Returns:' section to convey the action.

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 an example ('{"username": "hikaru"}') that implies usage for looking up a single player's profile, but it does not explicitly state when to use this tool over alternatives such as chesscom_player_stats or lichess_user. No when-not-to-use or alternative tool guidance is provided.

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