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

Beyond the annotations (readOnly/openWorld/idempotent/non-destructive), it discloses that it reads CDP discovery plus /.well-known/x402, issues one unpaid request per route, never pays, is HTTPS-only, blocks private targets, does not charge on errors, and costs $0.01 via x402 USDC on Base. That is unusually rich behavioral context for a read-only tool.

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 purpose and how to call it, then constraints, return shape, and pricing. Almost every clause earns its place, though the pricing/networks details add length that a shorter definition could compress.

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 no output schema, the description compensates by naming the return fields (verdict, per-route indexed status and networks, fail/warn findings with fix lines). Combined with cost, transport constraints, and side-effect disclosure, an agent has 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 parameter is already documented as 'host or https URL'. The description repeats this and adds only the HTTP verb (GET), so it meets but does not exceed the baseline where the schema carries the semantics.

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 a precise verb+resource ('find out whether an x402 seller is listed in Coinbase CDP Bazaar') and even covers the negative case ('and, if not, why'). It is far more specific than a tautology, but it never names or contrasts the closely related sibling x402_check, so the agent must infer which one applies.

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 gives a clear triggering condition ('Use to find out whether an x402 seller is listed... and, if not, why'), which is real usage guidance. It stops short of exclusions or naming the alternative x402_check for related diagnostics, so it is context-rich but not routing-complete.

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