Set the playback range in Houdini's timeline by defining start and end frames. Use it to control which frames play or render during scene review.
Set the playback range (green bar in the timeline).
Args: start: Start frame. end: End frame.
| Name | Required | Description | Default |
|---|---|---|---|
| end | Yes | ||
| start | Yes |
Changes observed during successful MCP inspections.
v2.24.1Input schema / additionalPropertiesAdded value: +falsev0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It never says whether the operation is a mutation of scene state, whether it is undoable, whether it clamps or validates the range, or what happens if start exceeds end. For a mutating tool with zero annotation coverage this is a substantial gap.
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?
Very short and front-loaded, with the key identification ('green bar in the timeline') up front. The 'Args:' block is boilerplate that merely repeats the parameter names, but it costs little.
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?
A two-parameter mutating tool with no annotations, no output schema, and 0% schema description coverage should say considerably more. Nothing about validation, side effects, or the distinction from set_frame_range is given.
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%, so the description must compensate. It adds only the unit ('frame') to each parameter, restating the schema's titles. It says nothing about ordering constraints, valid bounds, or whether values are integers.
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?
States a specific verb and resource ('Set the playback range') and usefully identifies the target as the green bar in the timeline, which disambiguates it visually. However it does not distinguish itself from the sibling set_frame_range, leaving the agent to guess which of the two range-setting tools to pick.
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?
There is no when-to-use guidance, no mention of prerequisites (e.g. that start must precede end or be within the scene range), and no reference to the near-identical sibling set_frame_range. The agent receives no routing information at all.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.