comp_add_transition

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

With no annotations, the description carries the transparency burden. It does disclose the core visible behavior and guarantees no overlap or duration change, which is genuinely useful. However, it omits side effects such as whether an existing transition is replaced, whether audio is affected, and whether the operation is reversible, so the disclosure is partial.

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 a single sentence with no filler. The core behavior is front-loaded, and the caveats ('no overlap', 'no change in duration', 'not a crossfade') are packed efficiently without repeating schema information.

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 tool with no annotations, no output schema, and four schema parameters at 0% description coverage, this description is incomplete. An agent cannot determine what after_clip_id refers to, what units duration uses, or what the tool returns. The behavioral description is clear, but the operational details needed to invoke the tool correctly are missing.

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 schema has 0% description coverage, so the description needed to explain comp_id, after_clip_id, duration, and type. It does not do this: after_clip_id placement, duration units, and the fixed fade_black type are all left implicit. The phrase 'no change in duration' is a behavioral statement, not an explanation of the duration parameter.

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 specifies the transition effect ('fade to black then back') and key constraints ('no overlap', 'no change in duration'), making it clear this is a dip-to-black transition rather than a crossfade. It relies on the tool name for the 'add transition' action, so it is clear but not fully self-contained and does not explicitly differentiate it from sibling add tools like comp_add_clip or comp_add_overlay.

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 'Not a crossfade' statement is a useful exclusion, and the no-overlap/no-duration-change constraints suggest where and how the transition should be placed. However, there is no explicit statement of when to prefer this tool over alternatives or what preconditions must hold, such as adjacent clips or a valid composition. Usage guidance is only implied by the transition description.

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