Add an audio track to the timeline

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

With no annotations provided, the description carries the full burden. It mentions that the tool is 'blocked in read-only mode' (indicating it is a write operation) and explains parameter defaults. However, it does not disclose potential side effects (e.g., whether adding an audio overwrites existing ones) or any permission requirements beyond read-only.

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 purpose in the first sentence, followed by essential parameter guidance and a note on read-only mode. It is concise (three sentences) with no wasted words.

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 tool's complexity (10 parameters, no output schema, no annotations), the description provides sufficient context for an agent to decide when to use the tool and how to set key parameters. It could be improved by mentioning other parameters (fadeIn, fadeOut, volume) and what the tool returns, but the core behavior is well covered.

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 significant meaning beyond the schema by explaining the difference between duration and sourceDuration, and by directing users to get_project for voiceover data. Schema coverage is 60%, and while some params (s3Key, fadeIn, fadeOut) are not addressed, the description compensates for the key parameters that differentiate use cases.

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 tool's purpose: 'Place an EXISTING audio asset on the timeline at a specific point so it's in the render.' This is a specific verb-resource pair, and it implicitly distinguishes from sibling tools like add_image_from_file or add_timeline_overlay by focusing on audio assets.

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 description provides guidance on when to use the tool (for an existing audio asset) and explains parameter choices: duration defaults to movie length (ideal for background music), while sourceDuration is for fixed clips like voiceovers. It also advises using get_project to obtain voiceover data. However, it does not explicitly compare with siblings or state when not to use this tool.

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