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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses non-obvious behavior: results are paginated, and item output differs by marketplace (amazon.se yields /dp/ASIN links when ASINs exist, other marketplaces fall back to search deep-links with catalogMode=search-ideas). That is real context an agent could not infer from annotations or schema. It does not mention rate limits or empty-result behavior.

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?

Four short sentences, front-loaded with purpose followed by marketplace caveat, the hard requirement, and sibling routing. Minor waste in the 'OpenAPI: getCatalog' pointer, but no sentence is padded.

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?

No output schema exists, yet the description sketches the return shape (paginated items, marketplace-dependent link format), and required parameters are called out. For a read-only browse tool the remaining gap is filter semantics, which is a parameter-level rather than a completeness failure.

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?

With 10 parameters and only 40% schema description coverage, the description needs to compensate, but it only addresses marketplace and locale — and the marketplace semantics it restates are already in the schema's own description. The eight filter parameters (q, ids, limit, offset, interest, occasion, styleTag, budgetBand) are undocumented in the description, leaving the agent to infer filtering behavior from enum values 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?

The description establishes a specific resource ('curated Mother's Day gift starters') and scope ('paginated'), and explicitly names search_gifts as the primary discovery path, so the agent can distinguish it from that sibling. The term 'starters' is slightly vague about what an item actually is, keeping it just 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?

'Search (search_gifts) remains primary discovery' gives explicit routing against the most likely alternative, and 'ALWAYS pass marketplace + locale' states a hard precondition. It does not state the positive trigger for choosing this tool (e.g. browsing curated gift ideas rather than searching), so it is clear context without full when/when-not coverage.

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