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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses substantial behavioral traits: the threshold default, the 60-ply truncation, the exact per-entry output composition, and the accepted input formats and colour filter. These details are not available in the annotations and are highly relevant to invoking the tool correctly. The description is fully consistent with 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 arranged efficiently: core behavior first, then return format, then input and limitation details. It is three sentences with no filler and no unnecessary repetition of schema content. Every clause contributes new, useful information for an agent.

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 there is no output schema, the description fully accounts for return values by listing every field in each entry. It also covers both accepted input representations, optional colour filtering, the threshold behavior, and the truncation limit. This is a complete picture for a read-only analysis 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?

The schema already provides 100% parameter coverage with descriptions for pgn, moves, colour, and threshold, so the description does not need to re-document them. The description adds a little context, such as the input alternatives and colour filtering, but mostly restates behavior rather than clarifying individual parameter semantics. This matches 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 contains a specific verb and resource ('Replays a finished game... returns the moves where the evaluation swung'), which makes the tool's purpose exact and easily distinguishable from the sibling tools. It also enumerates the returned fields, so an agent knows precisely what 'review' produces without needing the schema.

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 choose chess_review over the sibling tools chess_analyse or chess_attacks. It neither names alternatives nor states exclusions, leaving the agent to infer usage solely from the task wording. This is a clear gap given the sibling list is available for routing.

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