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

Annotations already declare readOnlyHint=true and no destructive behavior, so the description's disclosure of 'return a deterministic score and prioritized issue codes' adds useful output context beyond the annotations. It also specifies 'one public URL,' implying access requirements without contradicting the annotations.

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 sentence that front-loads the action and then lists items. It is slightly long but efficient, with no wasted words. The structure is readable and covers all key aspects without redundancy.

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?

The description covers the full scope of the audit by enumerating the checks, and mentions the output (deterministic score, prioritized issue codes), which is sufficient given that an output schema exists. It does not overexplain return values, so the description is complete for its intended use.

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?

With a single parameter (url) and 0% schema description coverage, the description adds minimal parameter guidance. It says 'one public URL,' which hints at accessibility, but does not clarify required format (e.g., including protocol). Since the parameter is simple and the schema already defines uri format, this is adequate but not exemplary.

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 starts with a specific verb+resource ('Audit one public URL') and enumerates a comprehensive list of SEO factors (title, meta description, H1 count, etc.), clearly distinguishing it from siblings like web.full-audit or web.metadata. It sets clear expectations for the scope of the audit.

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 implies a focused SEO audit but does not explicitly state when to use this tool over alternatives like web.full-audit or web.security-audit. There is no mention of when not to use it, leaving the agent to infer based on the listed checks.

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