compose

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

With no annotations, the description carries the full burden and it does disclose important behavior: the call returns immediately with a jobId, the agent must poll job_status, and concurrent jobs are rejected. This goes beyond the schema and gives the agent accurate expectations, though it does not mention overwrite behavior or cleanup.

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?

Two sentences with no wasted words: the first states the intended operation and target, the second gives essential async and concurrency guidance. The structure is front-loaded and easy to scan.

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 captures the core behavior (async job, single-flight, output file) and the schema covers parameters along with an output schema for return values. However, given the large sibling toolset representing a pipeline, it does not explain where compose fits in the workflow or when it should be called relative to render, captions, or gif, leaving room for agent uncertainty.

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 already documents all four parameters with 100% coverage, so the baseline is 3. The description adds no extra parameter-level meaning; it only mentions the output path, which is not tied to any specific parameter beyond the dir context.

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 identifies the operation ('Trim, sync, mux and caption') and a concrete deliverable ('output/final-demo.mp4'), so an agent can tell what compose accomplishes. However, it does not explicitly distinguish it from sibling tools like render, captions, or gif, which could also be involved in producing media outputs.

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 implies asynchronous usage ('Returns a jobId immediately — poll job_status') and a concurrency restriction ('Rejects if another job is running'), which helps an agent decide how to invoke it. It does not state when to choose compose over alternatives nor mention any prerequisites such as finished renders or recordings, leaving usage guidance mostly implicit.

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