Set or remove an expression for a specific layer property.
AI agents use setLayerExpression to create or update resources in After Effects MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your After Effects MCP Server environment.
This tool modifies a layer property by setting or removing an expression in Adobe After Effects. It creates or updates data (the expression) in a reversible way — expressions can be changed or removed. No code is executed externally, no data is permanently destroyed, and no financial transactions occur.
From the tool's definition Set or remove an expression for a specific layer property
Documented attack patterns abuse exactly the kind of access setLayerExpression gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and After Effects MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for setLayerExpression:
{
"version": "1",
"default": "deny",
"tools": {
"setLayerExpression": {
"limits": [
{
"counter": "setlayerexpression_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}setLayerExpression stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Set or remove an expression for a specific layer property. It is categorised as a Write tool in the After Effects MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the After Effects MCP Server MCP server in PolicyLayer and add a rule for setLayerExpression: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches After Effects MCP Server. Nothing to install.
setLayerExpression is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the setLayerExpression rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for setLayerExpression. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
setLayerExpression is provided by the After Effects MCP Server MCP server (thellamainator/after-effects-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from After Effects MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
30 After Effects MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.