Execute raw ExtendScript directly in After Effects to automate project manipulation, layer creation, animation, and rendering. Returns the last evaluated expression as a string.
Execute a raw ExtendScript snippet directly in After Effects
| Name | Required | Description | Default |
|---|---|---|---|
| script | Yes | ExtendScript code. The last evaluated expression is returned as a string. |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
There are no annotations, so the description carries the full burden of behavioral disclosure. It does not mention that executing arbitrary ExtendScript can mutate the project, has no undo, or may be destructive. It only states that the script runs and that the last expression is returned, leaving important safety behavior undisclosed.
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 sentence with no filler, and the core action is front-loaded. Every word contributes to identifying the tool's function, making it highly efficient.
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 an arbitrary-code-execution tool with no annotations and no output schema, the description is too thin. It does not mention when raw execution is appropriate, what the script can affect, or potential risks. The schema covers the return value, but the missing safety and usage context is a significant gap.
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 100% and the input schema already documents the script parameter and its return behavior. The description adds no additional parameter-level detail, so it correctly holds at the baseline of 3.
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 and resource: 'Execute a raw ExtendScript snippet directly in After Effects.' This distinguishes it from the many sibling tools that perform specific high-level operations, since it emphasizes raw, arbitrary script execution rather than a convenience wrapper.
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 given about when to choose this tool over dedicated siblings, such as ae_apply_effect or ae_add_expression, nor are any exclusions or prerequisites mentioned. The raw/direct wording implies it is a generic fallback for scriptable operations, but this is not explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.