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

Annotations already declare readOnlyHint=true and openWorldHint=false; the description adds real operational detail beyond them -- at most three outbound GETs, only status codes are read and never the response body, and no account is required. It does not describe the shape of the report returned, which matters since there is no output schema.

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 with the core claim and the payment precondition, with concrete behavioral facts (GET count, status-only reads) stated compactly. The trailing feedback-routing sentence is useful but stretches the definition across a second concern.

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?

Covers the prerequisite logic, cost, safety profile, and feedback path for a single-parameter read-only check. The main gap is that, with no output schema, it never states what the report contains (per-document statuses, a verdict), leaving the agent guessing at the return value.

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?

One parameter with 100% schema description coverage, which already explains that the URL must be publicly reachable and not a loopback/private address. The description adds no syntax or format detail beyond the schema, so the 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 and resource: checking whether YOUR service publishes a machine-readable discovery document (/.well-known/x402 or agent card). The 'free' and 'listable at all' framing clearly distinguishes it from siblings like placement_venues, placement_status, and listing_promote, which handle submission/promotion rather than the publishability prerequisite.

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?

Tells the agent the decision rule explicitly: if no document is published, no submission work can succeed and you should not pay before it is fixed. It also routes non-check intents (complaints, questions, quote requests) to POST /feedback. It stops short of naming specific sibling tools as the follow-up alternative.

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