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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description usefully adds that receipts are tamper-evident and HMAC-signed, but it never explains that issuance is a stateless signing operation (the basis for the readOnly claim) nor how verification is performed, despite advertising it. That ambiguity around "issue and verify" versus a single issue endpoint is the main shortfall.

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 compact sentences, purpose first and endpoint second, with no filler. The word "verify" is the one piece that does not earn its place, since no verification behavior follows from it.

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 four parameters, a nested action_input object and no output schema, the definition should say something about the returned receipt artifact or the verification path, but it does neither. For a security-signing tool, an agent still lacks the information needed to use the result confidently.

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%, so the baseline is 3; the description adds no meaning beyond the schema. It does not clarify the role of secret (signing key versus stored credential), the semantics of agent_id, or the shape of the nested action_input object that gets hashed into the receipt.

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 gives a specific verb-and-resource pair ("Issue ... tamper-evident HMAC-signed receipts") and names the audience ("autonomous AI agent actions") plus the concrete endpoint POST /v1/agent-action-receipts/issue, which lets an agent separate this from siblings like tinplate_consent_tokens or tinplate_content_provenance. The only blur is the phrase "Issue and verify", which implies a capability the stated endpoint does not expose.

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?

There is no when-to-use or when-not-to-use guidance, no stated prerequisites (e.g. secret provisioning), and no named alternative among the security-oriented siblings. The agent must infer applicability purely from the one-line purpose statement.

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