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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it is a polling endpoint, it returns status/progress, and mp4_url only appears when status is done. It omits failure/expiry states, but this is solid added context.

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?

Three short sentences, zero waste, and the polling purpose plus return contract are front-loaded before the account requirement.

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 correctly carries the return contract (status, progress, mp4_url when done) and notes the free-account prerequisite. It is nearly complete; only error/expiry behavior is missing.

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 coverage is 100% and the single job_id parameter is already documented in the schema as coming from render_youtube_clip. The description only reinforces that provenance without adding format or validation detail, so the baseline 3 is correct.

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 (poll), the resource (a clip render started by render_youtube_clip), and what it returns. An agent can immediately distinguish it from render_youtube_clip and from the other get_* siblings.

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 description ties usage to a preceding render_youtube_clip call, which is clear context for when to invoke it. It does not, however, state polling cadence, termination conditions, or what to do if the job id is unknown/expired.

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