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

The annotation already declares destructiveHint: true. The description adds behavioral details: it explains that 'none' clears the transition and that the exporter runs an ffmpeg xfade. This goes beyond the annotation without contradicting it, providing useful context about the effect and mechanism.

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 two sentences, front-loads the main action, and includes necessary details without any fluff. It is well-structured and concise.

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?

The description covers the main action and how to reference the clip, and mentions the exporter behavior. However, it does not describe the return value or error handling, which is important given there is no output schema and the tool is destructive. It is adequate but not fully complete.

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 adds meaning for clip_id by specifying its source (from get_timeline) and reinforces the 'none' value for type. It does not add anything for project_id or duration, though duration already has a schema description. With 50% schema coverage, the description partially compensates but not fully.

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 the action (set or clear transition) on a specific resource (clip's out-edge), explains the blend into the next clip, and mentions the ffmpeg xfade mechanism. It also clarifies the 'none' value for clearing. This is specific and distinguishes it from sibling tools like add/remove/reorder clip.

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 provides context that clip_id comes from get_timeline, which is a useful prerequisite. However, it does not explicitly mention alternatives or when not to use this tool. The purpose is clear enough that an agent can infer when to use it, but there is no explicit exclusion.

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