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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, covering safety traits. The description adds that lookup is by exact ID, but does not disclose any additional behavioral details (e.g., pagination, rate limits) beyond what annotations provide.

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 two sentences with no redundant text. It front-loads the core action and then lists acceptable inputs, making it efficient and easy to parse.

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 the presence of an output schema and annotations, the description covers the essential lookup functionality. However, it omits guidance on handling multiple parameters or the role of limit/entity/country, which may be needed for full autonomy.

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 67% (6 of 9 parameters have descriptions). The description lists valid ID parameters, adding some context, but does not explain the remaining parameters (limit, entity, country). It partially compensates but does not deliver complete clarity beyond the schema.

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 'Exact-ID lookup', specifying a precise verb and resource. It lists the accepted ID types (id, bundle_id, isbn, etc.), distinguishing it from sibling tools like search or search_within which support fuzzy queries.

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 indicates usage when an exact ID is available by stating 'Provide any one of...', which implies precise matching. It does not explicitly exclude other query types or compare with alternatives, but the context is clear enough for basic guidance.

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