set_playhead

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

With no annotations provided, the description carries the full burden. It transparently states both the mutating action ('Move the playhead') and the additional behavior of reading the position back. While it does not cover prerequisites like an active sequence, the core behavior is clearly disclosed for a simple state changer.

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 primary action and a practical use case. Every word earns its place, with no redundancy or filler.

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 one-parameter tool with no output schema and no annotations, the description is compact yet sufficient. It explains purpose, the parameter unit, and a concrete usage scenario. It could mention required context (e.g., an active sequence), but the description is largely complete for its complexity.

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 input schema has 100% parameter description coverage for 'time_seconds' ('Sequence time in seconds'). The description's mention of 'time in seconds' reinforces but does not add significant new information beyond the schema. The baseline of 3 is appropriate given high schema coverage.

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 clearly states the tool moves the playhead to a specified time and reads the position back. This is a specific verb+resource combination and distinguishes the tool from siblings like get_playhead (which presumably only reads) and export_frame (which captures at the playhead position).

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 explicitly mentions a key use case ('Useful before export_frame, since that captures wherever the playhead lands'), giving clear context for when to use the tool. It does not explicitly compare with alternatives like get_playhead, but the provided use case differentiates it from read-only tools.

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