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

With no annotations provided, the description fully discloses behavior: it starts with 'Read-only', explains the differential output with and without partNumber/partSlug, states that partSlug takes precedence when both are given, and notes that a not-found result is returned for missing models or parts. This covers the key side effects and conditional behavior an agent needs to anticipate.

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 five sentences with no filler; every sentence contributes either core function, usage routing, parameter behavior, or error handling. The lead sentence immediately conveys read-only status and main purpose, making it scannable.

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 tool with only 3 parameters, no output schema, and no annotations, the description covers all necessary decision points: when to use it, how to identify the build name, how to fetch a specific part, what the default return looks like, and error behavior. Nothing essential is missing for correct invocation.

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 coverage is 100% so baseline is 3, but the description adds meaningful combination semantics beyond the schema: it clarifies what happens when neither partNumber nor partSlug is provided, explicitly states precedence rules when both are present, and ties buildName to the browsing/identification flow. This elevates it above the baseline.

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?

Description states a specific verb and resource: 'Returns detailed information for one sailing-ship model' and lists included content areas. It clearly separates this from sibling tools by specifying 'for one known model' and 'do not use it for catalog browsing', so an agent can distinguish it from list_builds and list_model_slugs.

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 explicitly names alternatives: 'Use list_builds to browse or filter the model catalog' and 'use list_model_slugs when a model slug must be identified from a name or metadata'. It states the condition for using this tool ('when details for one known model are needed') and gives an exclusion ('do not use it for catalog browsing').

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