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

Annotations already declare read-only, idempotent, and non-destructive behavior; the description adds real operational traits: retry timing, signed-link expiry, final chargedSeconds, error/no-charge on failure, dictionaryCapacityApplied meaning, and balance in every response. These are exactly the non-obvious behaviors an agent needs beyond the 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?

Long but dense: every clause covers a distinct operational fact such as polling, completion, versioning, failure, dictionary capacity, and balance. The main action is front-loaded nored there is no filler or repetition of the annotations.

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?

Combined with the full input schema, output schema, and annotations, the description covers polling semantics, state transitions, output links, versioning, billing on failure, dictionary capacity, and the always-present balance. There is no material gap for an agent invoking get_caption_job.

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?

The single jobId parameter is already fully documented in the schema as an id returned by this API. The description adds the 'known job' framing and a fallback to list_caption_jobs for the lost-id case, but no new syntactic or format-level detail beyond what the schema provides.

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?

Opens with 'Poll a known job,' naming a specific verb and resource. It immediately differentiates from list_caption_jobs by defining get_caption_job as the tool for a known id, so an agent won't confuse the two.

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 tells when to poll this tool ('while it runs' with retryAfterSeconds) and when the id is lost to call list_caption_jobs instead. It also explains post-render behavior, including versioning semantics after render_captions, which is direct usage context.

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