chesscom_player_stats

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, covering safety and idempotency. The description adds valuable behavioral context beyond annotations: it specifies that a key is absent if the player has never played a format, and discloses that no authentication is required. This goes beyond the structured metadata.

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 and appropriately sized: it opens with the core purpose, then details the return shape, provides an example, and ends with authentication info. Every section earns its place without redundant fluff. The inline return structure is necessary since there is no output schema.

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 absence of an output schema, the description fully compensates by detailing the exact return structure (nested objects for each format, records, best ratings, etc.) and the edge case of missing keys. It also includes a practical example and notes that no auth is needed, making the tool's input and output completely clear for an agent.

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 already fully describes the 'username' parameter with 100% coverage, so the baseline is 3. The description adds value by providing a concrete example of the parameter usage ({"username": "hikaru"}), which clarifies how to specify the username in practice. This extra illustration enhances understanding beyond the schema.

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 retrieves a player's ratings and records per game type (blitz, bullet, rapid, daily, tactics, puzzle rush). It uses a specific resource (Chess.com player) and differentiates from sibling tools like chesscom_player by enumerating the exact statistics returned. The purpose is unmistakable and aligns with the tool name.

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 clear context for when to use the tool: when you need a player's ratings and records across various chess formats. It includes an example invocation and notes that no authentication is needed, but it does not explicitly mention alternatives or when not to use it, so it falls short of a 5.

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