verify_receipt

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

Annotations already declare this as read-only, idempotent, and non-destructive. The description adds valuable behavioral context: it performs offline verification, requires no authentication, and checks the Ed25519 signature against the receipt's embedded public key. This goes beyond annotation coverage.

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 three sentences, front-loaded with the core function, followed by the mechanism and a clear usage directive. Every sentence provides distinct value with no redundancy or 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?

Given the tool's simplicity (one parameter, no output schema), the description sufficiently covers what it does, how it works, and when to use it. It lacks explicit return-value formatting, but the purpose is clear enough for an agent to invoke it correctly.

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 coverage is 100% and the parameter description is adequate. The tool description adds meaningful extra detail about how the receipt is used (embedded public key, signature check) and clarifies the receipt format (vcr/1), enhancing understanding beyond the 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 clearly states the tool verifies any compliant claim receipt, specifies the method (structure + Ed25519 signature against embedded public key), and distinguishes itself from sibling tools by being issuer-agnostic, free, and offline. It also explains the exact use case: checking if a number an agent provided was actually verified.

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 provides clear context on when to use (before trusting a number from an agent) and highlights distinguishing factors (no api_key, no account, issuer-agnostic). However, it does not explicitly mention alternatives or when not to use this tool, so it falls short of a 5.

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