set_playhead

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

With no annotations, the description carries the full burden of behavioral disclosure. It states the action of moving the playhead but does not mention prerequisites (e.g., an open timeline), behavior on invalid timecode, or whether the operation has side effects beyond cursor movement. The mutation-like nature is implied but not elaborated.

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?

The description is two short sentences with no filler. The primary action is front-loaded, and the format clarification is directly relevant to invoking the tool. Every word earns its place.

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 simple one-parameter tool, the description conveys the core action and input format. Yet it omits prerequisites like an open timeline, error handling for invalid timecodes, and any expected return or side effects. The output schema may cover return values, but the description itself remains minimally complete.

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 schema provides zero description for the lone timecode parameter, so the description must compensate. It does specify the expected format ('HH:MM:SS:FF') and ties it to the timeline frame rate, adding needed meaning. However, it stops short of examples or details on frame-rate interpretation, leaving some ambiguity.

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 identifies the action ('Move') and the resource ('current timeline playhead'), which is specific and distinguishable from sibling tools. However, it does not explicitly differentiate itself from alternatives like timeline_frame or preview_timeline, so it misses the highest tier of clarity.

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 provides no guidance on when to use this tool versus other timeline navigation tools. The only usage hint is the timecode format, which addresses parameter formatting rather than tool selection. No exclusions or alternative conditions are given.

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