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

With readOnlyHint=false and idempotentHint=false already in annotations, the description explains *why*: each call records the tap and consumes the chip's one-time answer. It then goes well beyond annotations, decoding proof 'presence' vs 'identity', the meaning of verified:false/no_signature/signature_unchecked, and sandbox key behavior. This is unusually rich disclosure for a mutation-flagged verify tool.

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?

It is dense and long, but front-loaded with the core purpose and every clause carries load (exceptions, sandbox behavior, spend semantics). A few output-decoding details could be trimmed, but nothing is filler.

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 no output schema, the description takes on the burden of explaining return semantics (proof, proves, verified, reason) and does so thoroughly, including the subtle no_signature vs signature_unchecked distinction and sandbox fixture modes. Complete for a complex verification tool.

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 schema already documents all five parameters and the description's baseline is 3. The description adds real semantic value on top, clarifying that `signature` proves identity not presence while picc_data+cmac prove presence, and that uid is optional when SUN params or tap_url carry it.

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 a physical item by its Aeroz chip') and immediately distinguishes it from record-based tools: 'a database record proves a record exists, not that the object in front of you is the one it describes.' An agent can separate this from find_unit, trace_unit, and verify_passport_credential without opening the schema.

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?

Gives explicit when-to-use context ('Use this before trusting any claim about a physical unit') and an operational constraint ('Each call records the tap and spends the chip's one-time answer, so pass each SUN tap once'). It stops short of naming sibling alternatives by name, so it earns a strong 4 rather than a 5.

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