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

Beyond the readOnly/openWorld annotations, the description adds the crucial null-when-absent behavior, the structure of the returned ai_overview object, and an API-key auth requirement. It could add rate-limit or failure-mode details, but the existing additions go well 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, front-loads the primary behavior and return contract, and then adds the parameter family and auth requirement. No sentence is wasted.

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 24-parameter tool with no output schema, the description covers the key contextual gaps: what is returned, when it returns null, and that an API key is required. The schema handles the parameter details, so the description is sufficiently complete, though it could mention limitations such as AI Overview availability by vertical or domain.

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 coverage is 100%, so the input schema already documents all 24 parameters. The description only adds the high-level statement that it 'accepts the google_search parameters', which orients the agent but does not add per-parameter semantics. Baseline 3 is appropriate.

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 names a precise operation ('Return only the AI Overview Google generates for a search'), specifies the output shape (ai_overview with ordered text_blocks and cited references), and states the null case. It also signals its relationship to the general search tools by saying it accepts the google_search parameters, which helps distinguish it from siblings like google_search.

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 purpose statement implies when to use the tool (when the AI Overview answer is needed), but it never states when not to use it or points to an alternative such as google_search or google_ai_mode. The guidance is inferred from the description rather than explicit.

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