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

Annotations already declare readOnly/idempotent/non-destructive, yet the description still adds real behavior: the state machine values, that resultContentId becomes the new draft on completion for combine/motion-ad jobs, and that a failed combine is refunded automatically. The polling cadence and the underlying endpoint round out operational context an agent needs.

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 core definition and tightly packed with polling advice and result semantics; almost every clause earns its place. The '[read-only]' prefix and the endpoint parenthetical duplicate what annotations/schema already convey, a small redundancy.

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 and does so: state values, resultContentId meaning, and failure/refund behavior. For a single-parameter polling tool this is complete enough to call correctly, with only jobId provenance left implicit.

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 0% for the single jobId parameter, so the description must compensate. The endpoint wrapper (GET /api/v2/generate/status/{jobId}) implies jobId is a server-issued identifier, but it never says where to obtain it (e.g., the return of combine_clips/render_motion_ad) or its format, leaving the key gap only partially filled.

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: returns the status of an async job and enumerates the exact job types it covers (combine_clips, render_motion_ad, API video generation) plus the four possible states. This clearly separates it from mutation siblings like combine_clips or render_motion_ad, which start jobs rather than report on them.

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 concrete usage guidance: poll every 10-30 s because renders take about a minute, which tells the agent both when to call and how often. It lacks explicit when-not guidance or an alternative for canceled/expired jobs, so it stops short of a 5.

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