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

Annotations already cover the safe/idempotent/open-world profile, but the description adds genuine behavioral context: no payment credentials are sent, and a price-limit BLOCK does not imply a broken integration. That result-semantics guidance is valuable beyond the structured hints.

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?

The first sentence is well front-loaded, but the two middle sentences about ALLOW/BLOCK are defensive and read as caveats rather than actionable guidance. Every sentence is relevant but the caveats could be tightened.

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 an output schema present, return values needn't be explained, and annotations carry the safety profile. The description covers the essential semantics (what it inspects, credentials not required, how to read results), leaving only minor parameter documentation gaps.

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 only 25% with 4 parameters, so the description must compensate and largely does not. The phrase 'caller-selected comparison policy' loosely gestures at max_price_usd/expected_network, but method, formats, and the meaning of the comparison fields are undocumented anywhere.

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 (inspect) and resource (x402 payment challenge / endpoint) with clear scope: 'Free endpoint check for API developers launching or debugging x402.' It implicitly distinguishes itself from the audit sibling by framing ALLOW/BLOCK as policy decisions rather than 'launch certification,' but never names audit_x402_endpoint outright.

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?

Names the audience use case (launching or debugging) and clarifies that buyer-side inspection is available, implying usage context. However, it never explicitly states when to use this instead of audit_x402_endpoint or order_x402_remediation, leaving the routing to the reader.

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