pr_setClipProperties

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

Adds non-obvious behavior beyond the annotations: keyframes are ADDED, not replaced, and a static value on an already-keyframed parameter is refused unless replaceKeyframes:true. That refusal rule is exactly the kind of write-safety context annotations do not convey. It does not discuss multi-clip partial failure or whether supplied values are absolute, leaving minor gaps.

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?

Messages are front-loaded and every clause carries information; no filler. The dense parenthetical packing (units, coordinate origin, keyframe grammar) makes it slightly harder to scan, but nothing is redundant.

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 10-parameter mutation tool with no output schema and thin schema descriptions, the description supplies the units, keyframe representation and the keyframe-conflict rule an agent needs to call it correctly. Remaining gaps are return behavior and what happens when one clip in the array fails.

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?

With only 30% schema coverage, the description carries the parameter burden and does so well: units for scale (%), position ([x,y] px with 0,0 top-left), rotation (deg), anchorPoint (px), opacity (0-100) and volume (dB, 0=unity). It also defines the keyframe object shape (time in timeline seconds plus optional scale/position/rotation/opacity/volume/interpolation), which the schema leaves as an empty additionalProperties object.

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?

States a specific verb+resource with precise scope: Motion/Opacity (scale, position, rotation, anchorPoint, opacity) on video clips, volume dB on audio clips. This implicitly separates it from pr_setEffectProperties and pr_getClipProperties, but no sibling is named explicitly, so it stops short of an unambiguous 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?

Usage is implied by the property list rather than stated: an agent must infer that this is the tool for transform/opacity/volume and that pr_setEffectProperties handles effects. There is no explicit when-not guidance or named alternative, though the video-vs-audio split gives some routing signal.

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