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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so the safety profile is handled. The description adds genuinely new behavioral facts not in structured data: no x402 payment challenge, free call, and an HTTP GET equivalent URL for out-of-band fetching. It does not describe the response shape, but the content list largely covers that.

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 compact sentences, front-loaded with what the criteria are, then the usage cue and the free-access note. The parenthetical 'no payment required: call directly without payment (no x402 challenge; this tool is free)' says the same thing three times and could be one clause.

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 parameters, no output schema and rich annotations, the description covers what an agent needs: the subject matter, the reason to read it first, the cost, and an alternate fetch path. The phrase 'the exact fetch contract' is left undefined, but the HTTP equivalent line resolves it in practice.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The only 'parameter-like' element is the equivalence to GET /toll/readiness/criteria, which is handled cleanly.

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?

It states a specific resource and its exact contents: 'the nine criteria, the exact present/misshaped/absent rules, the scoring, and the exact fetch contract' for the Agent-Readiness Audit. That is far more precise than a tautology. It does not explicitly name the sibling criteria tools (manifest_criteria, observability_criteria, ergonomics_criteria) or contrast itself with readiness_precheck, so differentiation is implied by domain rather than stated.

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?

'Read these before paying for an audit — every audit is reproducible from them' gives a concrete trigger for calling it, and the free/no-x402 note removes the main hesitation about invoking a paid-looking flow. It stops short of saying when not to call it or pointing to readiness_precheck for the cheaper pre-check path.

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