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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), but the description goes well beyond them: it states no signature is verified and no chip answer is spent, and it explains the critical null semantics ('recalled:null means UNKNOWN, never report as not recalled'). That is exactly the behavioral context annotations cannot convey.

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?

Front-loaded with the core purpose and readable as a short set of dense sentences, each carrying distinct information (return fields, null semantics, sandbox behavior). Slightly long, but nearly every clause earns its place.

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?

There is no output schema, yet the description enumerates the returned fields (known, recalled, reason, severity, date, id) and explains the null/UNKNOWN case and sandbox resolution. Nothing an agent needs to interpret results or call it correctly is missing.

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% and there is a single parameter ('uid' documented as the chip UID), so the schema carries the parameter burden. The description adds only indirect meaning (e.g. sandbox keys resolve seeded chips first), which is not a parameter-level clarification, so baseline 3 applies.

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+resource ('check whether a specific unit is subject to an active recall') and scopes it to the register. It also explicitly disambiguates from verify_chip, so an agent can distinguish it from the sibling that checks genuineness.

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?

Explicit when-to-use trigger ('whenever a unit is about to be shipped, sold, dispensed, or installed') and an explicit alternative for a different concern ('use verify_chip for that'). Both positive and negative routing are present.

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