Lists After Effects property keyframes with time, value, interpolation, and temporal ease so you can inspect animation timing for a layer or comp.
After Effects: list keyframes of a property — time, value, interpolation and temporal ease.
| Name | Required | Description | Default |
|---|---|---|---|
| layer | Yes | Layer name or 1-based index. | |
| property | Yes | ||
| compositionName | No | Comp name; omit to use the active comp. |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false and closed-world behavior, so safety is covered. The description adds the shape of the returned data (time, value, interpolation, temporal ease), which is real value given there is no output schema. It omits ordering, behavior when the property has no keyframes, and unit/format conventions.
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?
A single sentence that front-loads the host app and the resource, with the returned fields appended compactly. No filler; only a minor cost that the app prefix could be inferred from the ae_ namespace.
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 read-only, three-parameter query tool with annotations carrying the safety profile and no output schema, the description covers purpose and return fields adequately. It still leaves the 'property' addressing format and empty-result behavior unexplained, which an agent needs to invoke it correctly on the first try.
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 67%: 'layer' and 'compositionName' are documented, but 'property' has no schema description and the tool description only restates 'of a property' without clarifying accepted forms (display name, path with '>', or match name). With two of three parameters described, the description does not compensate for the remaining ambiguity.
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 uses a specific verb (list) plus resource (keyframes of a property) and names the app (After Effects), which separates it cleanly from the many set/mutation siblings like ae_setKeyframe and ae_setKeyframeEase. It does not explicitly name a sibling alternative (e.g., ae_getProperties for static values), so it falls just short of 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?
It states what the tool does but never says when to choose it over ae_getProperties, ae_getCompState, or ae_getLayer, nor any prerequisite such as having a property with existing keyframes. The only usage hint ('omit to use the active comp') lives in the schema, not the description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.