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

Goes well beyond the destructive/not-idempotent annotations: it discloses that credits are spent per clip second, that a previously failed clip render was refunded so the user is not double-charged, that edited scenes are re-written into prompts first, and that the retry is refused without the content_edited flag. That is exactly the cost-and-side-effect context an agent needs before a destructive, billable call.

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?

The core action and the alternative are front-loaded, and each following sentence carries non-redundant cost or side-effect information. Slightly dense with the refund aside, but nothing is wasted.

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?

Complete on cost, side effects and failure routing for a billable mutation tool, and annotations carry the safety profile. The one gap is that it never says what comes back (job id / async job) or that the caller should poll get_job_status, and there is no output schema to fill that in.

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 description coverage is 100%, so job_id, content_edited and idempotency_key are already fully documented in the schema. The description adds context about when the content-policy retry applies but no new syntax or format detail beyond the schema, so the 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?

States a specific verb and resource ('Re-render every clip of a finished video') plus the recovery case (retry a render that failed at clip/stitch). It explicitly contrasts with retry_step and implicitly with regenerate_scene, so an agent can route without opening either 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?

Gives both when-to-use (failure at clip/stitch step, e.g. ran out of credits) and when-not ('For failures at other steps use retry_step'), naming the alternative. It also states the precondition for the content-policy retry path.

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