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

Annotations already indicate this is read-only and non-destructive. The description adds detail about what it returns (thumbnails, source pages, original URLs), which is useful. However, it does not mention rate limits, pagination behavior, or the meaning of the 'light' variant in the name, so it provides only moderate extra context beyond the 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?

The description is two sentences and every piece of information earns its place: the search intent, the output, and the use case. No filler or repetition, front-loaded with the main action.

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 7 parameters and a fully described schema, the description covers the purpose, output shape, and typical use. The only real gap is the unspecified 'light' naming and any limitations it might imply, which could matter for an agent deciding between multiple search tools. It still feels sufficiently complete for routine calls.

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 description coverage is 100%, so the baseline is 3. The description does not delve into any parameter semantics beyond saying 'Search Google Images,' which aligns with the `q` parameter. It adds no new information about `gl`, `size`, `color`, etc., relying entirely on the schema.

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 verb+resource: 'Search Google Images for photos and visual content.' It explicitly differentiates from sibling tools like google_search_light and bing_search by focusing on image search. The return format (thumbnails, source pages, original URLs) makes it unambiguous.

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 phrase 'Useful for finding reference images, illustrations, and visual content' provides clear context for when to use this tool. It implies it is the right choice for visual search but does not explicitly compare with alternatives or give negative exclusions, so it falls 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.