Update an existing contact
AI agents use update_contact to create or update resources in Mcp Afip — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Afip environment.
This tool modifies contact information reversibly. It is a Write operation because it creates or modifies data that can be reverted or corrected. In the context of an AFIP (Argentine tax authority) server dealing with invoicing and financial records, updating contact details could impact tax compliance, invoicing accuracy, and business operations, warranting medium severity.
From the tool's definition Tool name 'update_contact' and description 'Update an existing contact' clearly indicate modification of existing data without deletion.
Documented attack patterns abuse exactly the kind of access update_contact gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Afip, and nothing reaches the server without passing your rules. This is the rule we recommend for update_contact:
{
"version": "1",
"default": "deny",
"tools": {
"update_contact": {
"limits": [
{
"counter": "update_contact_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} update_contact 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 contact. It is categorised as a Write tool in the Mcp Afip MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mcp Afip MCP server in PolicyLayer and add a rule for update_contact: 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 Mcp Afip. Nothing to install.
update_contact 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_contact 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_contact. 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_contact is provided by the Mcp Afip MCP server (codespar/mcp-dev-latam). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Afip, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
1300 Mcp Afip tools catalogued and risk-classified — across an index of 43,000+ MCP servers.