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

Beyond the readOnly/idempotent annotations, it discloses the slow-flag threshold behavior, the 30-minute fail boundary, that a longer-than-expected run is reported as running rather than failed, and that a failed result indicates whether a retry consumes another monthly Diagnostic. These are non-obvious operational semantics an agent could not infer from the schema or annotations.

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 status enumeration and only then the timing thresholds; every sentence carries information. The retry/credit sentence is somewhat convoluted in phrasing, which keeps it just short of a 5.

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 carries the return-value burden itself and does so: it names the status field, start time, elapsed minutes, the slow flag, and the failure explanation. For a one-parameter polling tool this is complete.

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 0% and the single parameter is undocumented in the schema, but the description compensates by explaining that diagnostic_id is the id supplied by start_diagnostic and list_diagnostics. It does not restate the uuid format, but the provenance guidance is the more useful half.

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 names a specific verb and resource and enumerates the exact status values it reports (queued, running, completed, failed) keyed by diagnostic_id. It does not explicitly contrast with the sibling get_diagnostic, so an agent must infer that this is the lightweight polling view rather than the full-result view.

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 closing line '"is it ready yet?" at any point in the conversation' gives a concrete usage trigger and reinforces that repeated polling is acceptable. It also supplies timing expectations (5-10 minutes typical) that shape when calling is useful, but gives no explicit when-not guidance or rate-limit advice.

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