Verify a signed receipt

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

With no output schema, the description carries the return-value burden and does so well: it discloses that valid=true requires both signature pass and an explicitly supplied matching key, and that omitting the key yields crypto validity flagged as untrusted signer. That is substantive semantics beyond the readOnly/openWorld annotations and does not contradict them.

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?

Two tight sentences, front-loaded with the core action and then the conditional valid/public-key rule. No wasted text and the key caveat arrives early.

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?

No output schema exists, and the description adequately covers return semantics and the security caveat, making the tool safe to call correctly. The only shortfall is silence on the shape of the required nested receipt object, which an agent may need before invoking.

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?

At 50% schema coverage, the public_key behavior is reinforced by the description, but the required 'receipt' parameter — a nested free-form object — gets no explanation of its expected structure or fields. Marginal value added over the schema, no compensation for the gap.

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?

States a specific verb and resource — 'Verify an Ed25519-signed Elliot receipt and its digest' — plus the exact cryptographic scheme. This clearly distinguishes it from siblings like verify_changes, verify_url, or verify_outcome, which handle other artifact types.

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 explains the decision condition for supplying public_key (trusted signer identity vs. math-only check), which is real usage guidance. However, it never states when to reach for this tool versus the many sibling verify_* tools, leaving tool-level routing to inference.

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