capcut_add_keyframe

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

With no annotations, the description carries the full burden. It discloses that it creates real per-property animation (not static) and that it can add or replace keyframes. However, it does not mention mutation of the draft, persistence, or any error conditions, which are important for a mutating tool without annotation coverage.

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 paragraph that front-loads the core behavior, then gives a usage tip and the enum list. It is concise and to the point, though it could be better structured with separate sentences for each key point.

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 mutation tool with no output schema and no annotations, the description should explain more: whether changes are saved automatically, what happens on conflicting keyframes, and any time constraints. The description leaves these out, making it incomplete for an agent to call it correctly.

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 0%, so the description must explain all parameters. It explains atSec and value indirectly through the usage tip ('different atSec/value') and lists the property enum, but does not define units, ranges, or the roles of draft and segmentId. This is insufficient for a 5-parameter tool with no schema descriptions.

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 states a specific verb (add/replace), a clear resource (keyframe on a segment property), and distinguishes it from static value setting. It also lists the allowed property enum, making the tool's scope unambiguous and different from siblings like set_props or remove_keyframes.

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 explicitly instructs to call twice with different atSec/value to animate, which is a clear usage pattern. It implies the tool is for animation rather than static values but does not mention alternatives or when not to use it, leaving a minor gap.

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