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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context by fixing the exact shape of the returned record and explicitly delimiting what is excluded, which the annotations cannot convey.

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?

Two sentences, front-loaded with the returned-field inventory and closed with the important exclusion. The field enumeration is dense but every item informs the agent about the payload, so there is little waste.

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 describing the return value and does so field-by-field, plus notes omissions. Only minor gaps remain, such as behavior for an unknown or invalid product ID.

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% for the single product_id parameter, so the schema already carries the semantics. The description only restates the lookup is by ID and adds no format, validation, or error behavior beyond that, making the baseline 3 appropriate.

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 gives a specific verb (return) and resource (catalog index record for one product), then enumerates exactly which fields appear in that record. It clearly separates itself from a detail-fetching tool by naming the fields it will not return (title, images, description).

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 clause 'This is structured metadata only; it does not include the title, images or description' tells the agent when this tool is insufficient, which implies a sibling such as get_product_details is needed for content fields. It stops short of naming that alternative explicitly or stating prerequisites, so it is clear context without full routing guidance.

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