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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the description's added value is its disclosure of output shape and the non-obvious 'at most one extra per declared capability gap' rule, plus the owner-approval signal. It does not mention pagination, rate limits, or what happens if goals were never set, which would be the remaining behavioral gaps.

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 sequencing prerequisite, then the return contract, then the required next action. Every clause carries information; nothing is restated from the title or schema.

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 correctly shouldered the burden of describing the return payload, and it does so item by item. It stops short of explaining how goals are consumed or what 'declared capability gap' means operationally, which slightly limits an agent trying to predict result volume.

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 only 50%: api_key is documented in-schema while limit is not beyond its numeric bounds. The description rescues limit's meaning by framing it as a count of returned catalog items, but never states the cap of 20 or the default, so an agent still can't reason about upper bounds from prose alone.

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?

States a specific verb and resource: returns catalog items matched to the agent's goals, and enumerates exactly what accompanies each item (reasons, vetting status and basis, cautions, owner-approval flag). The phrase 'matched to your goals' plus the capability-gap bonus rule distinguishes it from generic lookups like search_library or get_library_item without needing to name them.

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?

'Use this after set_goals' gives an explicit precondition, and 'Show them to your owner before installing anything' gives a downstream workflow constraint. What's missing is any statement of when not to use this versus a sibling search/lookup tool, so the agent must infer that from names alone.

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