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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, so the safety profile is covered. The description adds valuable behavioral details beyond annotations: the per-call cost ($0.03) and the precise return format (pass bool, findings[] with id/severity/detail). No contradictions exist.

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 a single, efficient sentence that front-loads the audit targets, then lists cost and returns. No fluff, but it could be slightly more structured (e.g., separating input modes from return structure). Still concise and skimmable.

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?

With an output schema available (signal indicates has output schema: true) and annotations covering safety, the description provides enough operational details: inputs, cost, and return shape. It omits any edge-case caveats (e.g., what happens if URL fetch fails), but for a read-only audit this is acceptable given the surrounding context.

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 both parameters (url and html) are already documented with clear descriptions. The tool description adds no additional parameter-specific meaning, meeting the baseline for high schema coverage.

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 explicitly lists the SEO elements audited (title, meta description, H1, canonical, OpenGraph, structured data, lang) and names the return structure (pass bool, findings[]). This clearly distinguishes it from sibling audit tools (performance, security, WCAG, bundle) which target different concerns.

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 description specifies the two input modes (url vs html) and implies use for SEO checks, but gives no explicit guidance on when to prefer this tool over siblings or when not to use it. The 'when' is left to the agent's inference from the name and listed checks.

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