capcut_set_timeline

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 two non-obvious traits: the safe dry-run default and the destructive limit on duration (it cannot shorten existing segments). However, it omits other mutation-relevant behavior such as the requirement that CapCut be closed for a write (only visible in the schema), and what happens to unspecified settings.

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 short sentences with zero filler; the operation and its target are front-loaded and the two caveats (duration limit, dry-run default) follow immediately.

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 7-parameter mutation tool with no annotations and no output schema, the description covers the primary settings and the most important safety caveat, but leaves the write-safety precondition and side effects unexplained. 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?

Schema coverage is only 43%, so the description must compensate. It maps to most writable parameters (canvas size = width/height, fps, duration, colour space) and clarifies that duration means 'total duration' rather than a segment, but it says nothing about the required 'draft' parameter or the fps/duration value ranges beyond what the schema already covers.

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 names a specific verb ('Change') plus the exact settings affected (canvas size, fps, total duration, colour space) on a named resource (a draft), so an agent can distinguish it from capcut_set_clip or capcut_set_speed_curve. It does not explicitly name a sibling it is differentiated from, which keeps it short of a 5.

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?

There is no guidance on when to use this tool versus alternatives such as capcut_create_draft or capcut_set_clip, nor any prerequisites (e.g. CapCut must be closed). The only usage-relevant statements are constraints ('Duration cannot cut existing segments') and the dry-run default, not routing information.

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