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

Annotations already declare openWorldHint=true, idempotentHint=true, destructiveHint=false and readOnlyHint=false, and the description reinforces the read-but-billed nature with the 'billed on first result, free re-queries within validity' note. It also discloses polling states, error codes, and expiry behavior. However, the billing/readOnly nuance is the only place it goes clearly beyond the annotation layer, so this is a solid but not exceptional 3-4.

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 purpose, then walks through status handling, billing, result location, and expiry in a logical order. Slightly redundant: the billing point is restated in the bracketed closing note, which repeats the earlier sentence rather than adding information.

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 must carry the return contract, and it does: it names resultAvailable, status, errorCode, the result.npsJoinHistory path, and resultExpiresAt with the RESULT_EXPIRED terminal state. An agent has everything needed to call and interpret this polling 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% and documents the transactionId format (16-byte lowercase hex, 32 chars). The description adds useful provenance — that the id comes from the req_nps_join_history response for the same product — which the schema does not state.

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 (retrieve approval status and NPS join history result) via the transactionId issued by req_nps_join_history. It explicitly distinguishes itself from the sibling req_nps_join_history by naming it as the source of the id, so an agent can separate the request step from the result-retrieval step.

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 conditional guidance: AUTH_WAITING means wait for mobile approval, COLLECTING means re-query shortly with the same ID, and RESULT_EXPIRED after resultExpiresAt means a fresh authentication request is needed. When-to-call and what-to-do-next are both spelled out.

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