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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is clear. The description adds behavioral context by explaining the matching fields (id, title, keywords, description) and the return structure (feature id, title, standards status). This goes beyond the annotations and gives the agent a clear picture of the search 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?

The description is concise and front-loaded, with exactly two sentences that immediately identify the database ('caniuse') and the action ('find'). Every sentence earns its place: the first explains what it does, the second explains the return value and next steps. No wasted words.

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 that an output schema is present, the description does not need to explain return values in detail, but it still covers the key context: what database is used, how the search works, and what to do with the results. It lacks explicit edge-case handling (e.g., no matches, pagination), but for a search tool with a simple parameter set, it is reasonably complete.

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?

The input schema documents 'limit' with a description ('1-50 (default 10)') but leaves 'query' undocumented. The description compensates by explaining that 'query' is a keyword to match against the database, and provides concrete examples ('webp', 'flexbox', 'CSS grid'). This adds meaning to the query parameter beyond the bare schema definition.

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 the tool's purpose: to find web platform feature IDs in the caniuse browser-compatibility database by matching a keyword against feature id, title, keywords, and description. It gives specific examples ('CSS grid, container queries, or WebP') and distinguishes this tool from siblings like feature and support by explaining that the returned ID should be fed to those tools.

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 provides a clear usage workflow: use this tool to find caniuse feature IDs, then feed the ID to 'feature' or 'support'. It implies when to use this tool versus those alternatives. However, it does not explicitly discuss when to use 'search_within' or other sibling search tools, so it stops short of a 5.

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