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

Annotations already cover safety (readOnly, idempotent, openWorld, non-destructive), and the description adds materially beyond them: an explicit price of $0.005/call, the full result shape, and the comparison output structure. It does not mention failure behavior for unreachable or non-HTTPS URLs, but the paid-call cost disclosure is a genuine value-add.

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?

Purpose and output shape are front-loaded and dense, which is good, but the final 'Use to audit whether...' clause largely repeats the opening sentence and its parenthetical list. One redundant sentence against an otherwise efficient block keeps this at adequate rather than exemplary.

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 carries the burden of describing returns and does so by naming score, grade, checks[], fixes[] and the comparison fields. The eight check identifiers are listed but not individually explained, a minor gap for an agent deciding whether this audit covers what it needs.

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%, so baseline is 3, but the description goes further by specifying what passing peer actually produces — comparison {score_gap, behind_on[], ahead_on[], fix_first[]}. That tells an agent the comparative semantic payoff of the optional parameter, which the schema alone does not.

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?

Opens with a specific verb and resource — 'Audit a public HTTPS API for AI-agent discoverability and payability' — then enumerates the concrete outputs (score 0-100, grade, checks[], fixes[]). No sibling in the provided list audits agent-readiness, so the tool is unmistakable against neighbors like ai_adoption or product_brief.

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?

The closing sentence 'Use to audit whether a public API can be found and paid for by AI agents' restates purpose rather than giving selection criteria. The peer parameter is the only conditional guidance ('Add peer=... to compare'), and there is no statement of when not to use it or which sibling to pick instead.

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