preview_animationPlay or stop existing idle, walk, or attack clips in the real Blockbench animation timeline to inspect motion without creating or editing keyframes.
Select and play or stop an existing idle, walk, or attack clip in the real Blockbench animation timeline. Does not create or edit keyframes.
| Name | Required | Description | Default |
|---|---|---|---|
| clip | Yes | ||
| playing | No |
| Name | Required | Description | Default |
|---|---|---|---|
| ok | Yes | ||
| data | No | ||
| error | No |
Changes observed during successful MCP inspections.
v0.3.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare non-readonly, non-destructive, non-idempotent, so the agent knows this changes editor state safely. The description adds the key behavioral fact that playback happens in the 'real' timeline and that content is untouched, which is exactly the context annotations can't convey.
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 short sentences, front-loaded with the action, followed by the disambiguating constraint. No filler and nothing buried.
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?
Output schema exists, so return values needn't be explained, and purpose plus non-goals are covered. Minor gaps remain around playback switching behavior and whether the call fails if no project/animation exists, but the definition is sufficient to invoke correctly.
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. 'Select' maps to the clip enum and 'play or stop' implies playing=true/false, but it never names the parameters, states the default of playing=true, or says what happens if a clip is requested while another is playing.
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+resource: select and play/stop an existing idle/walk/attack clip in the real Blockbench animation timeline. The explicit negative scope ('Does not create or edit keyframes') clearly separates it from generate_animations and any keyframe-editing siblings.
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 exclusion ('Does not create or edit keyframes') tells the agent when not to use it, which is the most likely confusion given siblings like generate_animations. It stops short of naming an alternative or stating prerequisites (e.g., a project must be open), so it is clear context rather than full routing guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.