AI agents use apply_object_style to create or update resources in InDesign UXP MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your InDesign UXP MCP Server environment.
Applying an object style changes the visual properties and attributes of a page item (such as a shape, text frame, or graphic) but does not create, delete, or execute arbitrary code. It is a styling/formatting operation that can be undone, making it a Write action rather than Execute or Destructive.
From the tool's definition The tool name is 'apply_object_style' and the description states it will 'Apply an object style to a page item', which modifies the formatting/styling properties of an existing object in an InDesign document. This is a reversible modification operation.
Documented attack patterns abuse exactly the kind of access apply_object_style gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and InDesign UXP MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for apply_object_style:
{
"version": "1",
"default": "deny",
"tools": {
"apply_object_style": {
"limits": [
{
"counter": "apply_object_style_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}apply_object_style 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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Apply an object style to a page item. It is categorised as a Write tool in the InDesign UXP MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the InDesign UXP MCP Server MCP server in PolicyLayer and add a rule for apply_object_style: 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 InDesign UXP MCP Server. Nothing to install.
apply_object_style 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 apply_object_style 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 apply_object_style. 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.
apply_object_style is provided by the InDesign UXP MCP Server MCP server (theloniuser/indesign-uxp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 135 InDesign UXP MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
135 InDesign UXP MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.