AI agents use themes_set_slide to create or update resources in Propresenter — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Propresenter environment.
This tool modifies theme slide content, which is a Write operation—it creates or modifies data reversibly. Severity is medium because misuse could alter presentation themes affecting multiple slides/presentations, but the changes are reversible and don't delete data or execute arbitrary code. Confidence is 0.85 as the description is clear but lacks detail on scope of modifications.
From the tool's definition Tool name 'themes_set_slide' and description 'Update a specific slide in a theme' indicate modification of theme data. The verb 'Update' confirms reversible data change.
Documented attack patterns abuse exactly the kind of access themes_set_slide gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Propresenter, and nothing reaches the server without passing your rules. This is the rule we recommend for themes_set_slide:
{
"version": "1",
"default": "deny",
"tools": {
"themes_set_slide": {
"limits": [
{
"counter": "themes_set_slide_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}themes_set_slide 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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Update a specific slide in a theme. It is categorised as a Write tool in the Propresenter MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Propresenter MCP server in PolicyLayer and add a rule for themes_set_slide: 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 Propresenter. Nothing to install.
themes_set_slide 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 themes_set_slide 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 themes_set_slide. 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.
themes_set_slide is provided by the Propresenter MCP server (@alxpark/propresenter-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Propresenter, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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177 Propresenter tools catalogued and risk-classified — across an index of 43,000+ MCP servers.