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

The description goes well beyond the annotations (readOnly, idempotent, non-destructive) by explaining that receipts are Ed25519-signed, immutable, and describing the exact JSON envelope structure for both Phase 3 and Phase 4 variants. It also mentions the canonicalization method (JCS), providing deep context about the data returned.

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?

Every sentence in the description serves a purpose: purpose, use case, ID format, return structure, and verification alternative. The text is well-structured, starting with the core action and then adding necessary detail. No filler or repetition.

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 fully compensates by detailing the response format for both receipt types, including the fields inside receipt.paid. It covers immutability, signature coverage, and offline verification. This is complete enough for an agent to know exactly what to expect and how to use the result.

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 schema already fully documents receipt_id with example prefixes. The description adds meaningful context by explaining that rcpt_ and rrcpt_ correspond to Phase 3 and Phase 4, which helps agents understand the two possible response formats without needing external knowledge. This enriches the parameter, though the schema itself is already sufficient.

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 specific verb-resource pair: 'Fetch a TrustBench routing receipt by ID.' It clearly defines what the tool does and distinguishes itself from the sibling verify_receipt tool by positioning verification as a separate action. The scope is unambiguous.

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?

Explicitly states the typical use case: 'Use to verify what was paid, to whom, for what capability, and what the on-chain settlement reference is.' It also provides an explicit alternative for offline verification: 'use the verify_receipt tool with the returned JSON, or @trustbench/verify-receipt npm.' This gives clear when-to-use and when-not-to-use guidance.

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