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

Annotations provide readOnlyHint, idempotentHint, and destructiveHint, but the description adds critical behavior: the $0.005 USDC payment on Base or Solana, deterministic execution, exact incompatibility reasons, conservative normalized mappings, and x402 authorization/settlement. This goes well beyond the annotations and is essential for correct invocation.

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 sentences convey the purpose, cost, return value, and payment mechanism without redundancy. Each phrase earns its place, and the most critical information (cost and function) is front-loaded.

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?

Given two nested-object parameters and no output schema, the description explains the return value ('exact incompatibility reasons and conservative normalized mappings') and the payment/authorization flow. It does not give a concrete example or clarify edge cases (e.g., unsupported chains), but it is sufficient for an agent to decide and call the tool.

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 0%, so the description must compensate. It indirectly maps the two parameters by referring to 'one tool output' and 'the next tool input', which aligns with producerOutputSchema and consumerInputSchema. However, it does not explicitly define each parameter's role or JSON Schema format, leaving some ambiguity for an agent with unfamiliar parameter names.

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 explicitly states 'deterministic JSON-schema compatibility check between one tool output and the next tool input', which is a specific verb and resource. It also mentions returning exact incompatibility reasons and normalized mappings, distinguishing it from siblings like json_schema_validate and json_normalize.

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?

The description clearly provides context: it is for checking compatibility when chaining tools ('between one tool output and the next tool input'). It also notes x402-aware MCP clients can authorize/settle, implying usage in a payment-enabled workflow. However, it does not explicitly name alternative tools or state when not to use it.

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