playbar_control

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

With no annotations provided, the description carries the full burden and excels. It discloses the no-undo behavior, the internal path for step actions (via hou.setFrame with clamping), error conditions (non-finite increment or unavailable range), and the batch dispatcher's handling of undo segments. This goes beyond basic 'reads/writes' and provides operational nuances.

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 structured with a clear hierarchical breakdown of actions. Every sentence contributes technical value, such as the distinction between direct HOM calls and the step path, and the undo behavior. There is no padding or redundancy, and the content is front-loaded with the core purpose.

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 two-parameter tool with no output schema, the description is complete. It covers all action variants, error handling, clamping behavior, and undo interaction. Given the lack of annotations, it provides sufficient context for an agent to invoke the tool correctly without needing external knowledge.

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?

Despite the input schema having no descriptions for parameters, the description thoroughly explains the possible values of the 'action' parameter, including the exact semantics for each. However, it does not explain the 'ctx' parameter, leaving that to the schema's empty structure. The compensation is strong for the primary param but incomplete for the other.

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's purpose: playbar control for play/step/jump operations. It enumerates specific actions (play, reverse, stop, step_forward, step_backward, goto_start, goto_end) and distinguishes itself from sibling tools by emphasizing '运行态时间线写' (runtime timeline write) and 'no-undo' behavior, which is a unique scope.

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 implies usage context: it is for playback control, not for generic frame setting or DOP stepping as seen in siblings like set_frame or step_simulation. It specifies exact behavior for each action, effectively guiding when to use this tool, but it does not explicitly state when not to use it or name alternatives.

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