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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds the crucial non-obvious operational fact that no payment or x402 challenge is involved, which an agent could otherwise wrongly assume for a paid audit product, plus a stable HTTP mirror.

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?

The content scope is front-loaded and dense with useful specifics, but the payment clause is stated three ways in one parenthetical ('no payment required / call directly without payment / no x402 challenge; this tool is free'), which is redundant packaging rather than information. Trimming that and the raw URL would tighten it without losing meaning.

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?

For a zero-parameter read-only tool with no output schema, the description tells the agent what the payload covers (four named criteria areas with thresholds and evidence classes), that it is free, and that audits are reproducible from it — enough to decide to call it. Only the response format is left unstated.

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?

There are zero parameters, so there is no parameter semantics to document and the schema is trivially complete. Baseline of 4 applies; nothing in the description is needed or missing here.

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?

Names the exact resource (the published criteria for the tool-ergonomics/v1 Tool-Description Ergonomics Audit) and enumerates its four contents, so an agent knows what it will get. The verb is only implied by 'Read these', not stated as a retrieval action, and the distinction from ergonomics_audit/ergonomics_precheck is inferential rather than explicit.

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?

Gives concrete timing guidance — 'Read these before paying for an audit' — and justifies it with 'every audit is reproducible from them', which is a real usage rule. It stops short of naming the sibling tools it replaces or saying when not to call it, but the sequencing advice is clear enough to act on.

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