Set a keyframe on any After Effects layer property at a specific time by providing composition, layer, property path, time, and value.
Add a keyframe to a layer property at a specific time
| Name | Required | Description | Default |
|---|---|---|---|
| time | Yes | Time in seconds | |
| value | Yes | The value at this keyframe | |
| comp_name | Yes | Composition name | |
| layer_name | Yes | Layer name | |
| property_path | Yes | Property path using dot notation |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of explaining side effects and mutation behavior, but it only states the basic action. It does not disclose whether an existing keyframe at the same time is overwritten, whether the property must already be keyframeable, or any error/return behavior.
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 clear sentence with no filler or repetition. It is appropriately concise for a simple tool, though it does not enrich the schema in any way.
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 mutating tool with no annotations and no output schema, the description is sparse. It leaves unanswered important contextual details such as the effect of adding a keyframe to a non-keyframeable property, what happens on failure, and whether the operation replaces or inserts at the given time.
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 description coverage is 100%, so all five parameters are already documented with meaningful descriptions. The tool description adds little beyond that, but since the schema handles the heavy lifting, a baseline score of 3 is appropriate.
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 states a specific action ('Add a keyframe') and target resource ('a layer property at a specific time'). It is understandable and distinct from generic get/delete/interpolation tools, though it does not explicitly differentiate itself from the closely related sibling ae_add_keyframe_sequence.
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?
No guidance is provided about when to use this tool versus alternatives such as ae_add_keyframe_sequence, ae_set_layer_property, or ae_get_keyframes. The intended use is implied but not explicitly stated, and no exclusions or prerequisites are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.