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

Annotations already declare readOnly/openWorld/idempotent, and the description adds materially beyond them: the free tier returns only score, grade and category scores, while findings, prioritized fixes and snippets require the paid endpoints at stated prices. This tiering and pricing disclosure is exactly the kind of behavioral detail annotations cannot carry.

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?

Two sentences, front-loaded with the purpose and then the tier/pricing structure; the long parenthetical category list is dense but each item earns its place by telling the agent what is checked. Slightly heavy in the middle but no filler.

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 compensates well by spelling out what the free preview returns versus the paid tiers. Minor gaps remain around runtime, failure behavior for unreachable sites, and rate limits, but nothing essential to calling 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?

Schema coverage is 100% and the single `url` parameter is already documented with format examples and the public-http/https constraint. The description adds no further syntax or normalization rules, so the schema does the heavy lifting and 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?

States a specific verb+resource ("AI-agent readiness audit of a website") and immediately enumerates the exact dimensions scored (robots.txt, llms.txt, OpenAPI/MCP/A2A, speed/HTTPS), so an agent knows precisely what the tool examines. No siblings exist to differentiate from, but the purpose is unambiguous without opening the 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?

Clearly frames the tool's usage context by describing the free preview tier versus the paid x402 tiers and what each returns, which effectively tells the agent when a result will be sufficient. It stops short of stating explicit preconditions (e.g., site must be publicly reachable) or when-not-to-use cases, but with no siblings the alternatives discussion is largely moot.

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