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

Annotations already establish the safety profile (readOnly, idempotent, non-destructive, non-open-world), and the description adds traits annotations cannot convey: it is free but rate-limited, results come from the index rather than a live probe (staleness), and the unknown-URL fallback path. This is exactly the extra context the scoring bar rewards.

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-loads cost and scope in the first sentence, then gives 'Use when' / 'Not for' / fallback in tight sequence. No sentence is redundant and each carries routing or cost information.

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?

An output schema exists, so return-value detail is unnecessary. For a one-parameter read tool, the description covers cost, freshness limitation, sibling routing, and the unknown-URL recovery path — everything needed to invoke it correctly.

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 url parameter already has a format constraint and a worked example. The description only echoes the parameter as 'one x402 endpoint URL', adding 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 ('coarse status and quality score for one x402 endpoint URL') plus the scope constraint ('from the index only, no fresh probe'). An agent can distinguish this from settled_check and settled_preflight without opening any schema.

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?

Uses explicit 'Use when:' and 'Not for:' clauses, names the two alternative tools with their cost/freshness tradeoffs, and routes the unknown-URL case to settled_submit. Nothing about when to pick this tool is left to inference.

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