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

Beyond the annotations (readOnlyHint=true, destructiveHint=false), the description discloses important behavioral traits: idempotency, Ed25519 signing, commitment to inputs/sources/times/dates, and the scope of attestation (checks, not compliance outcomes). This significantly enriches the agent's understanding of the tool's side effects and guarantees.

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 dense but efficient. It front-loads the primary action and packs critical details (idempotent, signed, read-only, legal disclaimer) into two coherent sentences with no filler. Every clause serves a purpose.

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 moderate complexity (two parameters, nested bundle object, output schema present) and rich annotations, the description is complete. It covers purpose, behavior, limitations, and the non-decision status, leaving no significant ambiguity for an agent deciding to invoke it.

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% (both bundle and createdAt have detailed descriptions). The description adds meaning by explaining that the bundle contains preflight results and that the receipt commits to inputs, sources, retrieval times, and validity dates, which clarifies the expected content of the 'bundle' parameter beyond the schema's brief mention.

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 specifies a clear action ('Bundle the preflight checks ... into one idempotent Ed25519-signed receipt') and resource (receipt). It distinguishes itself from sibling tools by focusing on packaging all preflight checks into a single attestation, rather than performing individual checks like EORI validation or cost estimation.

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 for when to use the tool (after preflight checks, to create provable evidence) and explicitly states exclusions ('not a customs decision or clearance', 'not customs/tax/legal advice'). It does not explicitly name alternative tools, but the sibling list makes it clear that individual check tools are alternatives for specific checks.

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