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

With no annotations, the description carries the disclosure burden, and it does well: it states the output contents, the exact pay-per-call cost ($0.04 USDC on Base via x402), and the error behavior when the payment-signature header is missing. It does not cover rate limits, additional auth requirements, or whether the operation mutates anything, but those are less critical for this analysis tool.

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?

Three sentences, all essential: one defines the core function and result, one states the cost, and one explains the failure mode. The most decision-relevant information is front-loaded, and there is no redundant phrasing.

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 simple two-parameter read-only analysis tool, the description covers the return value, pricing, and error behavior. There is no output schema to communicate the response shape, so a bit more detail about the exact response format would have been useful, but the essentials for calling the tool correctly are present.

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 description does not need to elaborate on parameters. The description adds context around the output and payment, but it adds no meaning about 'query' or 'context' beyond what the schema already provides. 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 specific verb ('Analyze'), a resource ('SEO keywords'), and a subject ('for a topic'), and details the output ('top 10 keywords with search volume estimates and difficulty scores'). This clearly distinguishes it from sibling tools like analyze-competitors or analyze-sentiment, which target different analysis areas.

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 use case is implied by the domain-specific purpose: an agent should use this when SEO keyword analysis is needed. However, there is no explicit guidance about when not to use it, which alternatives might be better suited for related but different tasks, or what distinguishes it from the other analyze-* siblings.

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