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

Discloses non-obvious runtime behavior well beyond the annotations: one page scanned per call, results retained for 15 minutes, and required re-invocation with identical arguments until complete. This is exactly the kind of stateful/caching detail that is consistent with (and enriches) the idempotentHint=false annotation.

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?

Front-loaded with the core comparison purpose and reasonably sized for a feature-rich tool, but the long enumerated list of outputs is dense and slightly run-on. Nearly every phrase carries information, so little should be cut.

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 the output schema exists and return values need not be explained, the description covers everything an agent needs: what is compared, the 1-page-per-call cadence, the 15-minute retention window, and the repeat-call protocol. Nothing material is missing for correct invocation.

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% and all three parameters are documented in the schema, so the baseline is 3. The description only restates that competitors are 'up to 3' and that keyword is for keyword-use comparison, adding no syntax or format detail beyond 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?

States a specific verb (compare) and resource (a page vs up to 3 competitor pages ranking for the same search), and enumerates the concrete comparison dimensions. This is clearly distinguished from siblings like compare_html and compare_ai_citations by scoping the comparison to ranking competitors.

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?

Gives a clear use context (competitor pages ranking for the same search) and an unusual but important usage rule: because it scans one page per call, multiple new pages require repeated calls with the same arguments. It does not name explicit alternatives or when-not-to-use conditions, 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.