AI agents use update_person to create or update resources in Twenty CRM MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Twenty CRM MCP Server environment.
This tool creates or modifies data reversibly by updating person records in the Twenty CRM database. It does not delete data (which would be Destructive), execute arbitrary code (Execute), or handle financial transactions (Financial).
From the tool's definition Tool name 'update_person' and description 'Update an existing person' indicate modification of existing data in the CRM system.
Documented attack patterns abuse exactly the kind of access update_person gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Twenty CRM MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_person:
{
"version": "1",
"default": "deny",
"tools": {
"update_person": {
"limits": [
{
"counter": "update_person_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_person 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 an existing person. It is categorised as a Write tool in the Twenty CRM MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Twenty CRM MCP Server MCP server in PolicyLayer and add a rule for update_person: 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 Twenty CRM MCP Server. Nothing to install.
update_person 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_person 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_person. 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_person is provided by the Twenty CRM MCP Server MCP server (mhenry3164/twenty-crm-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Twenty CRM 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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23 Twenty CRM MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.