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

With no annotations, the description carries the full burden of behavioral disclosure. It does provide useful context: it returns a ready markdown report and includes pricing/cost information. It does not disclose potential side effects, network request behavior, rate limits, error handling for invalid URLs, or authentication requirements, leaving some uncertainty.

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 short and front-loaded with the core function and output details. The trailing '?url=https://example.com [HTTP x402 price: $0.99]' is slightly noisy, but it communicates the invocation example and cost without bloating the text.

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 one-parameter tool with an output schema, the description covers the main purpose, the expected input example, and the high-level output format. It does not provide explicit selection guidance, but that is addressed in the usage_guidelines dimension; otherwise nothing essential is missing for basic 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 0%, but the description offers a concrete invocation example '?url=https://example.com' and clarifies that the tool acts on a domain. This gives agents a usable input format beyond the bare schema. It does not explain optionality or null behavior, but with only one optional parameter this is a meaningful improvement.

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 states that the tool produces a full SEO audit report for a domain and enumerates concrete outputs: health score, prioritized issues, title/description/H1/canonical, robots.txt review, and word count. It is specific and easy to understand, though it does not explicitly name sibling tools such as api_seo_meta or api_robots_audit to differentiate them.

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 phrase 'Full SEO audit report' implies this tool is for comprehensive domain audits rather than narrower SEO checks, giving some usage context. However, there is no explicit when-to-use guidance, no mention of alternatives, and no exclusions, so an agent must infer when to choose this over related sibling tools.

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