brand_mentions

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

No annotations exist, so the description carries the full load. It usefully discloses that this is a paid call costing 0.08 USDC on Base via x402 and that results carry source page and sentiment. It does not cover retry/failure behavior, rate limits, or authentication beyond the payment rail, leaving gaps for a paid mutation-adjacent endpoint.

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?

A single front-loaded sentence carrying purpose, return shape, index, and cost with no filler. The stacked parentheticals are dense but each earns its place; nothing 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 3-parameter paid tool with no output schema and no annotations, the description adequately names the returned fields and the cost, and confirmNewPurchase handles repeat purchases in the schema. It still leaves the limit/pagination semantics and any failure behavior unexplained, so it is only just sufficient.

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 67%: keyword and confirmNewPurchase are documented in the schema, but 'limit' (integer, default 20, max 50) has no description anywhere. The description adds no parameter meaning at all - it never mentions paging, result caps, or the re-purchase flag, so it fails to compensate for the undocumented limit parameter.

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 resource and what it returns: web mentions of a brand or keyword with source page and sentiment, and identifies the underlying index (Content Analysis). This is clear enough to distinguish it from siblings like news_search or keyword_metrics, though it never names those alternatives explicitly.

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?

No when-to-use guidance is given. With many SERP/keyword/news siblings (news_search, serp_report, keyword_metrics, llm_share_of_voice), the description never says when brand_mentions is the right choice rather than one of those. The only conditional guidance lives in the confirmNewPurchase schema field, not the description.

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