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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description still adds substantial behavioral detail: nothing is published, a private/malformed address yields a 422 that is not charged, latency 4-12s (max ~35s), price USD 0.01 with no free tier, and an untrusted-data warning for returned text. This is unusually rich disclosure beyond the structured fields.

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?

Front-loaded with the purpose and alternatives, and most sentences carry distinct information (pricing, timing, error behavior, security note). It is long and slightly awkward ('Returns runs the agent-readiness check, then returns file bodies'), with some overlap between the output enumeration and the return-behavior sentence, so not a 5.

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?

An output schema exists, so return-value layout need not be spelled out, yet the description still names each generated file and its path/content-type nature. Combined with error, timing, cost, and safety guidance, an agent has everything needed to call this correctly.

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 the baseline is 3, but the description adds meaning the schema does not: skills, an OpenAPI URL, and an MCP endpoint that the check cannot discover are taken from the request. It does not explain content_signal defaults or the url origin-only constraint in more depth than the schema already does, so it stops short of 5.

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 (generate) and resource (agent-ready files) and enumerates the artifacts produced: robots.txt lines, llms.txt skeleton, api-catalog, MCP server card, skills index. It also names the two sibling tools it is not (check_agent_readiness, check_robots_txt), so an agent can separate it from the scoring/checking tools without opening any schema.

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?

Explicit routing: 'To only score a site use check_agent_readiness; for one URL's robots rule use check_robots_txt.' It also states the negative condition ('Generation only, nothing is published') and notes when request-supplied skills/OpenAPI/MCP values are used. When-to-use and when-not are both covered.

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