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

The annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely new behavioral context: the film is restored 'exactly as it was rendered' (no re-encode) and lands 'as one change, before any other change,' implying a single atomic edit that supersedes the current film. It stops short of saying what happens to the existing film's later edits.

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?

Two sentences, front-loaded with the triggering situation before the mechanics, with no filler. The phrasing 'as one change, before any other change' is slightly dense but carries real ordering information.

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 two-parameter, fully documented, non-open-world tool with rich annotations and no output schema, the description covers the trigger, the identifier source, exactness, and atomicity. Remaining gaps — behavior on a jobId from another project and whether unrendered edits are discarded — are minor for this complexity level.

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%, and the schema already explains that jobId is answered by render_video and list_renders and that projectId nulls to the open project. The description reinforces this by pointing at list_renders for identifying the right export, but adds no syntax or edge-case detail beyond the schema. Baseline 3 is appropriate.

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 — put an earlier export's film back as this project's film, exactly as rendered. That is concrete and distinguishable from list_renders, which it positions as a lookup helper. It does not explicitly contrast with similarly named siblings like replace_film or patch_film, which an agent might also consider.

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 an explicit trigger condition: use this when the person asks to go back to an earlier version they were sent. It also names the discovery route — list_renders with this projectId shows which export is which by when it was made — so the agent knows how to obtain the jobId. No when-not guidance is given (e.g. what to do if the exported version is stale or the wrong project).

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