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

Annotations already cover readOnly and destructive safety, so the main added behavior is the selection filter: only queries with multiple competing pages are returned. The description does not disclose details like ordering, default metrics, or output shape, but with annotations present this is acceptable.

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 one tight sentence that front-loads the core result and includes the key qualifier 'more than one page'. No filler or repeated schema content.

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 report tool with no output schema, the description gives only a high-level return concept ('with how each page does on them') and does not specify metric fields or ordering. The parameter schema documents has_more and defaults, which helps, but the absence of an output schema leaves the response shape partly underspecified.

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 descriptions cover 100% of the six parameters, including defaults and overrides such as start_date overriding days and min_impressions being per page. The description adds no parameter-level meaning, so the baseline of 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 clearly identifies the output: queries where multiple site pages are shown, with per-page performance. The title 'Pages competing for one query' captures the cannibalization concept and separates it from single-query or single-page tools, though it does not explicitly name a sibling alternative.

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 intended use case is implied by the cannibalization framing and by the 'more than one page' condition, but the description gives no explicit when-to-use guidance or comparison to page_queries, query, or find_opportunities. An agent must infer when this report is preferable to its siblings.

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