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

Annotations already indicate read-only, idempotent, open-world behavior. The description adds valuable details beyond annotations: a bound of eight external HTTP requests, no JavaScript execution, and caching behavior. It also integrates SSRF protection from the schema. No contradictions.

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 two sentences: first defines purpose and contents, second explains constraints and caching. No fluff, information-dense, and front-loaded. Every sentence adds value.

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?

Given rich annotations, an output schema, and clear listing of included features, the description is nearly complete. It covers purpose, behavioral constraints, caching, and SSRF. The only minor gap is the lack of explicit guidance for selecting this tool over siblings, but that is already accounted in usage_guidelines.

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?

Both parameters have descriptive schema comments covering meaning and constraints. The description restates the fresh parameter's caching advice but adds no new semantic information beyond the schema. Baseline 3 is appropriate given 100% 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 clearly states the tool's purpose: inspect a public HTTP/HTTPS URL and return a structured site passport. It lists specific content types (pulse fields, registrable domain, robots, sitemap, feeds, OpenAPI hints, page metadata), distinguishing it from siblings that focus on individual aspects.

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?

While the description gives usage tips for the 'fresh' parameter and mentions efficiency (8 requests, no JS), it does not explicitly guide when to use this tool versus its many siblings (e.g., web.url.pulse, web.site.robots). A sentence like 'Use for a comprehensive site overview; for specific data see related tools' would improve it.

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