Define the animation playback range by setting start frame, end frame, and frame step for timeline scrubbing and playback.
Set the animation playback range.
Args: start_frame: Start frame. end_frame: End frame. frame_step: Step between frames.
| Name | Required | Description | Default |
|---|---|---|---|
| end_frame | No | ||
| frame_step | No | ||
| start_frame | No |
Changes observed during successful MCP inspections.
v3.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the action and lists parameter names. It does not mention whether the range applies to the active scene, if it overwrites existing settings, or any side effects. For a mutation tool, this is insufficient.
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 extremely concise, with the core action stated first and parameters listed clearly. No unnecessary words or repetition. It is well-structured and front-loaded, but this conciseness contributes to the lack of depth noted elsewhere.
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 setter with three parameters and no output schema, the description still lacks essential context. It does not explain what 'playback range' affects (e.g., viewport vs render), nor does it guide the agent on when this tool is appropriate. The absence of usage guidance and behavioral details makes it incomplete for confident invocation.
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 description provides one-line glosses for each parameter ('Start frame.', 'End frame.', 'Step between frames.'), which adds meaning beyond the schema's property titles. However, it doesn't elaborate on units, inclusivity, or constraints. Since schema description coverage is 0%, the description must compensate, and it barely does.
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 'Set the animation playback range.' This is a specific verb+resource that distinguishes it from siblings like set_animation_cyclic (cyclic behavior) and go_to_frame (jump to a frame). The purpose is unambiguous and does not require the schema to be understood.
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?
No guidance is given on when to use this tool versus siblings such as go_to_frame or set_animation_cyclic. There is no mention of prerequisites, exclusions, or alternative tools. The agent has to infer when this is appropriate, which is a significant gap given the many animation-related tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.