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

The description adds substantial behavioral context beyond the annotations: it writes ordinary transform and crop values, replaces the clips' geometry animation, and arranges clips in cell order. It also warns that non-overlapping clips produce no visible layout, which is important for correct use.

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 front-loaded with the core action, then efficiently covers layout choices, mode and bias semantics, replacement behavior, and the overlap prerequisite. The enumeration is long but necessary, and no sentence appears wasted.

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 destructive mutation tool with seven parameters, nested bias, and no output schema, the description provides enough context to invoke it correctly: what it writes, what it replaces, how layout and mode work, and when the operation is visible. Missing return-value details are minor here because there is no output schema and the schema documents the token and ids.

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?

Although schema coverage is already 100%, the description adds meaning the schema does not carry directly: it enumerates all layout ids, explains that the first clipId maps to the first cell, and clarifies fit versus cover plus bias behavior. This is valuable parameter-level guidance beyond the schema text.

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 gives a specific verb and resource: arranging clips into a screen layout by writing transform and crop values. It is clear what the tool does, but it does not explicitly distinguish itself from siblings such as set_clip_properties or manage_effects.

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?

It gives a clear applicability condition: the clips should overlap in time on different tracks, otherwise the layout has no visible effect. It does not name alternative tools or state when not to use this one, so it falls short of full when/when-not/alternatives guidance.

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