Create video player

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

Annotations already indicate mutation (readOnlyHint=false) and non-destructive behavior (destructiveHint=false). The description adds concrete behavioral detail by naming the created TOPs, the exposed controls, the Null output, and the return value (clip paths, Null path, playlist flag). It does not overclaim safety or omit major side effects.

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 four sentences, front-loaded with the core purpose, then covers input modes, alternatives, return values, and integration context. Each sentence contributes useful information; it is slightly long but appropriately dense rather than verbose.

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?

Given the medium complexity, the description covers what the tool builds, how to invoke it with different file inputs, what controls are exposed, what it returns, and how it fits into a VJ workflow. With no output schema, the explicit return description is valuable and makes the tool effectively self-contained for an agent.

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 coverage is 100% and the schema already explains files, parent_path, and expose_controls in detail. The description restates and slightly contextualizes the file modes ('Pass file paths, or none to get an empty player') but does not add new parameter-level semantics beyond what the schema provides.

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 starts with a specific verb and resource: 'Build a movie/clip player inside a new video_player container' and explains the internal architecture (Movie File In TOP, Switch TOP, Clip selector, Null TOP). It clearly distinguishes this from create_video_synth, its most similar sibling.

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?

Explicit guidance is given: 'Use create_video_synth instead when you want a procedurally generated image rather than playing a video file.' It also tells when to combine with create_layer_mixer or bind_to_channel for VJ clip playback, and explains the three file-count modes (0, 1, 2+).

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