chesscom_monthly_games

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description adds substantial behavioral context beyond these: the return format (games array with specific fields), that 'end_time' is UNIX SECONDS, that a prolific player's month can be several MB, and that no authentication is needed. This warns the agent about potential payload size and response structure, which is valuable beyond the annotations.

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 front-loaded: the first sentence states the purpose, followed by the return format, a key note on time units and size, a concrete example, and auth requirement. Every sentence earns its place, and the formatting is scannable and efficient.

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?

With no output schema, the description carries the burden of explaining return values, and it does so thoroughly. It specifies the nested structure of games, highlights the high-risk 'several MB' size, provides a realistic example, and states auth requirements. This is complete for a read-only, idempotent data retrieval tool.

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?

Schema description coverage is 100%, with each parameter clearly described (e.g., 'Two-digit month, ZERO-PADDED'). The description adds an example (hikaru, 2025, 01) but this largely reaffirms schema details rather than providing new semantic information. The baseline of 3 applies because the schema handles parameter documentation, and the description adds minimal extra 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 tool's function: 'Every game a player finished in one month, with PGN, result, ratings and opening ECO.' This specifies the verb (finished/returns), resource (games), and scope (one player-month), distinguishing it from sibling tools like chesscom_player or chesscom_player_stats which focus on profiles or aggregate stats.

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 use: it returns games for a specific player in a month, with an example showing required parameters. However, it does not explicitly state when not to use it or mention alternative tools for other scenarios (e.g., getting stats or archives), so it lacks explicit exclusions or alternatives.

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