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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior. The description adds useful context about the catalogue size (~3,700 lines), what the returned deviation information means, and external links, though it omits error behavior for invalid or unknown sequences.

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 front-loaded with the core purpose and then lists return details in a single additional sentence. It is efficient and informative, though the return list is somewhat long given that an output schema already exists.

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 annotations covering safety and an output schema present, the description supplies enough context for correct invocation: input formats are explained, catalogue scope is noted, and output content is previewed. Nothing critical is missing for an agent to call this 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%, so the single moves parameter is already documented. The description provides an example and confirms SAN movetext/PGN support, adding only marginal meaning beyond the schema's own description.

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 states a specific verb and resource: identify the chess opening of a move sequence. It is highly clear about scope and input formats, but does not explicitly differentiate itself from the sibling get_opening_guide, so it falls short of a 5.

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?

Usage is implied by the input formats (SAN movetext or full PGN), but there is no explicit guidance on when to choose this tool over analyze_game, analyze_position, or get_opening_guide. No when-not or alternative conditions are provided.

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