Execute arbitrary ExtendScript in After Effects for automation, project modifications, and JSON-serializable returns using function bodies with parameters.
Execute arbitrary ExtendScript in AE. Code is a function body: use return for a JSON-serializable result; access parameters as args. May modify projects and files. ES3 syntax is recommended for AE 2024+.
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes | ||
| parameters | No |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so description carries full burden. Discloses that it may modify projects and files, which is critical. Recommends ES3 for AE 2024+, but does not mention error behavior, timeouts, or the execution environment, leaving some uncertainty for a potentially dangerous operation.
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?
Three sentences, each providing distinct value: purpose, code format, and side-effect warning with syntax note. Efficient and well-structured, though could be slightly more detailed without much added length.
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?
Provides essential information for executing code: purpose, code format, and side effects. However, lacks details on error handling, whether AE must be running, or any constraints, which is significant for a tool that runs arbitrary code. Output schema absent, but return guidance helps. Overall, adequate but with gaps.
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 0% schema coverage, description adds meaning to the code parameter by specifying it's a function body and how to return a result, and explains the parameters object is accessible as args. This compensates for the lack of schema descriptions, though it could give more detail on parameter structure.
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?
Clearly states it executes arbitrary ExtendScript in AE, specifying verb, resource, and context. Distinguishes from siblings like run-command by emphasizing the arbitrary script execution in AE.
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?
Provides clear context on how to format the code (function body, return value, parameter access) but does not explicitly state when to use this tool over alternatives like run-command, nor when not to use it. Lacks tool-selection guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.