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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), and the description adds concrete operational context beyond them: the exact resources fetched, the six-category scoring model, and a rate limit (5 live audits/hour) plus 'free, no auth'. These are non-obvious constraints an agent needs.

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 dense sentences with no filler; the core action and fetch list are front-loaded, followed by the sibling differentiation and the operating constraints. Every clause carries information.

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 no output schema, the description still indicates the return content ('scored on the six on-page categories with concrete recommendations'). Combined with the live-vs-stored distinction and rate limits, nothing an agent needs to call it correctly is missing.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents 'domain' with an example. The description adds no additional syntax or format guidance, which is the expected baseline when the schema does the heavy lifting.

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 verb (run) and resource (live AEO audit) and enumerates exactly what is fetched and how it is scored. It explicitly distinguishes itself from the sibling aeo_score by contrasting live fetch vs stored index value.

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?

Names the alternative tool (aeo_score) and the condition that selects it ('returns the stored score from the index; that score updates when Engagemii next reads the site'), so an agent can route between live and cached audits without inference.

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