x402 inspect

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

Annotations already declare readOnlyHint and openWorldHint, so the safety bar is lower; the description still adds that no signature or payment ever occurs and that the URL is transmitted to api.cdp.coinbase.com, which is genuinely useful disclosure of external data flow. It does not describe the shape of the returned decode/validation result.

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?

Two tight sentences, with the most decision-relevant fact ('Free, never signs or pays') front-loaded, followed by the mechanism and the data destination. No filler.

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 two-parameter, read-only probing tool with full schema coverage, the description covers what it does, its cost/safety profile, and where data is sent. The main omission is what the response contains, which matters slightly since no output schema exists.

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 both parameters are already documented in the schema, including the GET/POST enum and default. The description adds no semantics about the method parameter or URL constraints, so 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 specific verbs and objects: fetch an https URL unpaid, decode its x402 payment-required header, and validate via Coinbase CDP. The vague name 'inspect' is fully disambiguated, and none of the siblings (embed, summarize, ask, health) overlap with this capability.

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?

'Free, never signs or pays' gives clear selection context: use this to probe an x402 endpoint without spending or authenticating. It stops short of explicit when-not guidance (e.g., when to skip inspection and pay directly), but no sibling competes for this job.

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