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

With no annotations, the description carries full behavioral disclosure. It states the operation is free, unauthenticated, makes one round-trip, moves no funds, defines the unsigned vs signed behavior, and details the exact server-signature recovery address and verification steps.

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 description is front-loaded with the core purpose, then uses numbered levels and paragraphs to organize mode-specific details. Every sentence carries operational value; no filler or repetition exists.

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 the tool's cryptographic complexity and zero annotations, the description is complete enough to invoke correctly: it explains both call modes, input requirements, expected response elements, block-age thresholds, and post-call verification. The presence of an output schema further reduces the need to document return types.

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?

Input schema has 0% description coverage with only names, types, and defaults, but the description explains all three parameters: signature is the agent's EIP-712 ping signature, and nonce/timestamp must match what was signed. It could be more explicit about formats, but it substantially compensates for the sparse schema.

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 names a specific verb and resource: checking whether the x402-agent-pay.com settlement pipeline is alive and current. It also clarifies scope with 'one round-trip, no funds moved,' which distinguishes it from settlement or payment-execution siblings like check_payment_readiness and get_spend_authority.

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 explains exactly when the tool matters by giving liveness thresholds ('<= 12s is live, > 30s treat as down') and instructs agents to verify server-signed block age before settling through this facilitator. It does not explicitly contrast with sibling tools, but it provides strong situational guidance for using the signed vs unsigned modes.

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