AI agents use update_property to create or update resources in Fabric Ontology MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Fabric Ontology MCP Server environment.
The tool updates properties of ontology items, which is a reversible modification (Write category). Severity is high because ontology changes can affect data governance, entity relationships, and workspace-wide metadata in Microsoft Fabric, potentially impacting downstream queries and analytics.
From the tool's definition Tool name 'update_property' combined with server description stating 'full CRUD control of Ontology items' and 'update' operations modifying ontology properties.
Documented attack patterns abuse exactly the kind of access update_property gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Fabric Ontology MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_property:
{
"version": "1",
"default": "deny",
"tools": {
"update_property": {
"limits": [
{
"counter": "update_property_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} update_property 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_property. It is categorised as a Write tool in the Fabric Ontology MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Fabric Ontology MCP Server MCP server in PolicyLayer and add a rule for update_property: 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 Fabric Ontology MCP Server. Nothing to install.
update_property 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 update_property 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 update_property. 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.
update_property is provided by the Fabric Ontology MCP Server MCP server (tmdaidevs/ontology-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Fabric Ontology MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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45 Fabric Ontology MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.