check_frames

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

With no annotations, the description carries the full burden and does disclose two useful behaviors: frames reflect the EDITED timeline (not the source media) and overlays/captions are composited in. It omits the cost/latency of rendering, whether the project must be saved first, and whether the operation is read-only.

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, zero filler, with the purpose and the output form front-loaded before the usage directive. Every clause carries information the agent needs.

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 moderate-complexity render tool with no annotations and no output schema, the description adequately explains what comes back (a single labelled grid) and the edited-timeline semantics. It remains incomplete on parameter meaning and on the practical cost/behavior of rendering.

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% across four parameters, and the description clarifies only one of them implicitly: frames are sampled at 'timeline times' rather than source times. Nothing is said about width, columns, or the project identifier, including how width/columns relate to the 'labelled grid' layout.

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?

"Render frames of the EDITED timeline at the given timeline times ... return them as one labelled grid" states a specific verb (render) and resource (frames), plus the output shape. It does not explicitly distinguish itself from the siblings render_preview or timeline_contact_sheet, so the agent must infer that difference.

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?

"Use after every edit to verify it" gives a crisp triggering condition that fits into an edit loop. It stops short of naming alternatives or exclusions (e.g., when to use render_preview or timeline_contact_sheet instead).

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