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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered and the description earns credit for adding lifecycle facts: the download link expires in one hour and must be re-fetched, and the audio itself is retained for 24 hours. Those are non-obvious constraints an agent cannot infer from structured fields. It does not mention auth or behavior for an unknown/expired job_id, which keeps it off a 5.

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?

Two sentences with no filler: the first front-loads the possible statuses, the second front-loads the returned artifact and its expiry. Every clause carries information an agent needs.

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?

For a one-parameter read tool with no output schema, the description effectively sketches the return surface (status values, download link with TTL, 24-hour retention). Only edge behavior for an invalid or long-expired job_id is unstated, which is a minor gap for this complexity.

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?

There is a single required parameter with 100% schema description coverage, and the schema already says job_id is 'the id returned by create_speech_job'. The description repeats that provenance rather than adding format, validation, or failure semantics, so the schema carries the weight and 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?

Names the resource (a job from create_speech_job) and enumerates the exact state machine it reports: queued, running, completed, failed. That is specific enough to distinguish it from create_speech_job, estimate, list_voices, and get_usage without opening a 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?

The phrase 'from create_speech_job' plus 'call again for a new one' establishes the poll-after-create workflow and explains why a repeat call is legitimate. It stops short of explicit exclusions (e.g., when to use estimate or text_to_speech instead), so it is clear context rather than full when/when-not guidance.

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