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

Annotations already give the safety profile (readOnlyHint=true, destructiveHint=false), so the description only needs additive context — and it supplies the full status lifecycle plus the long-poll behavior of wait_seconds, which is a real runtime trait. The note that 'while pending, the card shows the AltID QR code again' discloses a UI side effect the caller would not otherwise expect.

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?

Three short sentences, front-loaded with the status vocabulary, then the wait semantics, then the pending-state UI note. Every clause carries information an agent needs; nothing is padded.

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 correctly takes on the burden of enumerating return states, which is the main thing the caller needs. It leaves minor gaps — e.g. behavior on an unknown/expired-too-long id and whether repeated polling is expected — but is largely self-sufficient.

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 50%: wait_seconds is already documented in the schema (including the 25-second cap), so the description's restatement adds little. age_check_id has no schema description, and the description only implies its role (something you pass to place_order) rather than explaining where it comes from — likely start_age_check. Minimum-viable for a two-parameter tool.

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 ('Status of an age check') and enumerates the exact state values the tool can report (pending, approved, failed, expired, revoked), which no sibling does. This clearly separates it from start_age_check, which initiates the flow rather than reporting on it.

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?

Explicitly routes the agent forward: 'approved (pass age_check_id to place_order)' tells it what to do with the result, and 'wait_seconds (max 25) waits while pending' tells it when to poll versus return immediately. No statement of when not to use it or what happens for the non-pending terminal states.

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