AI agents use update_document to create or update resources in ERPNext MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your ERPNext MCP Server environment.
The tool modifies existing records in an ERP system, which is a Write operation. Severity is high because ERPNext is a business-critical system handling financial, inventory, and operational data. Misuse could corrupt records, create audit issues, or cause business process failures.
From the tool's definition Tool name is 'update_document' and description states 'Update an existing document in ERPNext'. This modifies existing data reversibly.
Documented attack patterns abuse exactly the kind of access update_document gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ERPNext MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_document:
{
"version": "1",
"default": "deny",
"tools": {
"update_document": {
"limits": [
{
"counter": "update_document_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_document 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 document in ERPNext. It is categorised as a Write tool in the ERPNext MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the ERPNext MCP Server MCP server in PolicyLayer and add a rule for update_document: 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 ERPNext MCP Server. Nothing to install.
update_document 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_document 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_document. 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_document is provided by the ERPNext MCP Server MCP server (rakeshgangwar/erpnext-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 11 ERPNext MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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11 ERPNext MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.