engine_info

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

Discloses caching behavior (5-minute cache) beyond annotations. Annotations already declare readOnlyHint etc., and description adds no contradiction. Clearly states it's a discovery-only tool.

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 sentences, front-loaded with purpose. Every sentence adds value: purpose, return format, usage hint, caching, and disambiguation from search. 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 zero parameters, good annotations, and presence of output schema, description fully covers tool behavior. Explains response grouping, caching, and non-search nature. No gaps.

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?

No parameters exist, so baseline is 4. Description adds value by explaining what is returned (list grouped by category) and caching, but no param info needed.

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?

Clear verb 'Get' and resource 'search engines and categories'. Explicitly distinguishes from search tool by stating it does not perform web search, and from autocomplete implicitly.

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?

Explicitly states when to use: before calling search with filters. Clearly says what it does not do (no web search) and points to the search tool, providing both usage context and alternatives.

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