AI agents use set_active_source to create or update resources in ParaView-MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your ParaView-MCP environment.
This tool modifies ParaView's application state reversibly—changing the active source does not delete data or execute arbitrary operations, but it does alter the visualization pipeline configuration. This is a write operation (state modification) rather than a read (which would only query the active source).
From the tool's definition Tool name 'set_active_source' and description 'Set the active pipeline object by its name' indicate modification of ParaView's internal state by changing which visualization object is currently active.
Documented attack patterns abuse exactly the kind of access set_active_source gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ParaView-MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for set_active_source:
{
"version": "1",
"default": "deny",
"tools": {
"set_active_source": {
"limits": [
{
"counter": "set_active_source_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_active_source 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 the active pipeline object by its name. It is categorised as a Write tool in the ParaView-MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the ParaView- MCP server in PolicyLayer and add a rule for set_active_source: 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 ParaView-MCP. Nothing to install.
set_active_source 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 set_active_source 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 set_active_source. 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.
set_active_source is provided by the ParaView- MCP server (llnl/paraview_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from ParaView-MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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23 ParaView-MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.