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

Annotations declare readOnlyHint=true and destructiveHint=false, and the description is consistent with that while adding real context: no API key required, public https sites only, and the important caveat that a pass does not mean a crawler or agent will actually use the site. It stops short of describing rate limits, error behavior, or what a failing check looks like.

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 tightly packed sentences with the free/no-key qualifier front-loaded, followed by the action and the result caveat. Nothing is padded or redundant.

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 usefully enumerates what gets checked and warns that a pass is not a guarantee, which covers the main interpretive gap. It still does not indicate the shape of results (pass/fail vs. detail) or failure handling, leaving a small omission for a 1-param tool.

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 coverage is 100% for the single 'url' parameter, and the schema already states 'Public https site URL'. The description restates the 'public https site' constraint but adds no format, scheme, or validation detail beyond the schema, so the baseline 3 applies.

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?

Specific verb and resource: reads a public https site and returns readiness checks for robots.txt, llms.txt, agents.json, descriptions, and skill.md. The scope is unusually concrete, but it never names or contrasts a sibling (e.g. x402_listing_check, meter_scan), so an agent must infer the distinction.

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?

'Free. No API key.' plus the alias 'Same as POST /api/v1/agent-check' give partial context about cost, auth, and the equivalent REST endpoint. There is no explicit when-to-use versus sibling tools and no statement of when not to use it, so usage is only implied from the name and scope.

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