Verify a receipt offline

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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses meaningful behavior: it is independent of QED Proof's servers, does not read the blockchain, reports the anchor as unchecked, and caps trust level at 1. It also reveals the default key source. This gives an agent a realistic model of side effects and limitations.

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?

Four dense sentences, each carrying distinct value: what it checks, what it does not check, input modes, and key resolution. The core purpose is front-loaded and there is no redundant restatement of the schema or title.

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?

The description covers all invocation decisions, trust-level consequences, and key resolution, making it complete enough for an agent to call safely. It references the QED Proof spec for the exact checker semantics and describes the report's limitations, so the absence of an output schema is not a blocking gap.

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?

Although the schema already covers all parameters at 100%, the description adds orchestration semantics: the offline-vs-fetch distinction between receipt_json and receipt_id, and the fallback behavior for keys_json from the issuer's published poaw-keys.json. This is exactly the extra meaning an agent needs to choose the right parameter combination.

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 and resource: 'Checks a receipt independently of QED Proof's servers' and enumerates the exact verification steps (JSON Schema, integer-only encoding, Ed25519 signature, Merkle proof). This clearly distinguishes it from sibling retrieval tools like get_receipt and get_verdict, so an agent knows what the tool is for without reading schemas.

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 gives concrete invocation guidance: pass receipt_json for a fully offline check or receipt_id to fetch first, and explains that keys_json may be omitted in favor of the issuer's published poaw-keys.json. It also warns that the on-chain anchor is not checked, which sets expectations, but it does not explicitly route to alternative siblings such as get_verdict when a higher trust level is required.

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