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

With no annotations, the description carries the full behavioral burden and does so well: it discloses the 60-second memory constraint, audio retention, per-minute cost, job_id polling behavior, and result-link expiration. These are exactly the traits an agent needs before invoking an async media job.

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?

Four tightly packed sentences. Purpose is front-loaded, then constraints, cost, and async handling follow in a logical order with no redundant or filler content.

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 no-output-schema tool, it covers everything needed to call correctly: what it does, clip-length limit, cost, async job behavior, polling tool, and result expiry. Only parameter specifics are missing, and those are partly covered by the schema.

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 description adds no parameter-level information: it never mentions url, format, or max_height. Schema coverage is only 67%, and the undescribed format enum must be inferred from the schema alone, so the description fails to compensate for the gap.

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 states a specific verb and resource: 'Play a short clip backwards, with its audio.' It is immediately distinguishable from general media-editing siblings like edit_video or trim_media.

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?

It gives clear operational context: 60-second limit, credit cost, async job polling via get_job, and one-hour link expiry. It does not explicitly name alternatives such as trim_media or edit_video, so it stops short of full when-to-use guidance.

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