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

Beyond the annotations (readOnly, idempotent, openWorld, non-destructive), the description discloses meaningful behaviors: it never moves funds or retries payments, public blockchain data needs no auth while provider state requires an API key, and it explicitly warns that onchain finality does not prove beneficiary bank credit and 'unknown never means failed.' This is exactly the kind of contextual behavior annotations alone do not convey.

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 longer than average, but every sentence earns its place: purpose, triggers, input formats, output semantics, auth requirements, and safety guardrails. It is front-loaded with the core use case and uses plain, direct language. Though verbose, there is no fluff.

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?

Despite having no output schema, the description summarizes the return value (normalized state, flags, health, diagnosis code, suggested action, retry timing, and knowledge model) so an agent knows what to expect. It also covers authentication, input requirements, and post-call safety behavior, making it complete for the tool's complexity.

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?

The input schema already fully describes both parameters (100% coverage), but the description adds domain-specific meaning by enumerating supported identifier forms (Base transaction hash, Solana signature, Bridge transfer ID, Circle payment ID, wallet address) and instructs the agent to ask the user for an identifier if none is provided. This adds behavior around the input parameter beyond the schema's generic description.

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 opens with a precise statement of what the tool does: determining whether a stablecoin payment completed, failed, or is delayed, including where the money is and who owns the next step. Typical triggers like 'the recipient says the payment never arrived' make the purpose unmistakable. It does not explicitly contrast with sibling tools get_trace or list_supported_systems, so an agent must infer differentiation from the detailed output description.

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 explicitly states when to use the tool ('Use this whenever you need to determine...') and gives typical user trigger phrases. It also provides a clear exclusion: do not use it to send or swap anything, and if a payment is unresolved, do not send a replacement. However, it never names alternative sibling tools or conditions for choosing them, so it stops short of a full 5.

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