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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description still adds useful context beyond them: it explicitly disclaims authorization, purchase, settlement, execution, and record creation, and names the sole return state. No output details are needed since an output schema exists.

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 and compact: the defining trait ('FREE read-only') and the return value come first, followed by a tight negation list. The list of five negative verbs is slightly redundant but each forecloses a plausible misreading of 'execution'.

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 annotations covering safety, an output schema covering the return, and full schema coverage on the only parameter, the description is nearly complete for the call mechanics. The remaining gap is ecosystem-level: no routing guidance among many closely related audit/check siblings in a 21-tool set.

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% and the single parameter item_id is fully documented in the schema, including its provenance from offers.list. The description adds no syntax or format detail beyond the schema, so the baseline of 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?

The description states the tool is a 'read-only execution preflight' that returns READY_FOR_HUMAN_AUTHORIZATION, which conveys the gating/readiness function more than the name alone. However, 'preflight' is abstract and the description never clarifies what the check actually validates, nor distinguishes it from close siblings like requirements.check, result.preview, machine_commerce.readiness_audit, or x402.compatibility_audit.

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?

It never says when to call this vs. any of the ~20 sibling tools, nor what prerequisite state (e.g., a prior offers.list call) is needed before invoking it. The only implicit guidance is 'FREE' implying it is cheap to call, which is weak.

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