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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful behavioral context by stating that results are citable and carry an explicit verification status, and that the tool returns search results rather than full details. No contradiction with annotations.

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?

Three short sentences that front-load the tool's purpose, summarize output characteristics, and close with clear routing guidance. Every sentence earns its place with no filler or repetition.

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 search tool with an output schema and safety annotations, the definition covers the search scope, key result characteristics, and the relationship to `fetch`. Pagination and `authority_status` semantics are left to schema defaults and enums, which is acceptable, though a brief note about `list_topics` for topic slugs would make it fully airtight.

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 only 20% schema description coverage, the description compensates by defining the `query` parameter as matching title, official title, description, or topic, and by mentioning verification status, which relates to `authority_status`. It does not explain `limit`/`offset` mechanics or all filtering semantics, but the schema provides defaults and enum values for those.

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 action ('Search') on a defined resource ('Italian world and international days') and enumerates the searchable fields: title, official title, description, or topic. It also distinguishes itself from the sibling `fetch` by directing users there for details.

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?

Provides a clear routing instruction with 'Use fetch for details,' which clarifies when to use this tool versus the sibling. However, it does not explicitly discuss when to choose `list_days` or `list_topics` instead, so the guidance is clear but not exhaustive.

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