Create a new credential for workflow authentication. Use get_credential_schema first to understand required fields for the credential type.
AI agents use create_credential to create or update resources in n8n Workflow Builder MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your n8n Workflow Builder MCP Server environment.
This tool creates and stores credentials (authentication secrets) which is a reversible write operation. However, the severity is elevated to 'high' because credentials are sensitive security artifacts—misuse could grant an AI agent the ability to create backdoor access credentials, impersonate users, or establish unauthorized authentication pathways in the workflow system.
From the tool's definition Tool creates a new credential for workflow authentication. Description states 'Create a new credential' which is a write operation that persists authentication secrets to the n8n system.
Documented attack patterns abuse exactly the kind of access create_credential gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and n8n Workflow Builder MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_credential:
{
"version": "1",
"default": "deny",
"tools": {
"create_credential": {
"limits": [
{
"counter": "create_credential_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_credential 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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Create a new credential for workflow authentication. Use get_credential_schema first to understand required fields for the credential type. It is categorised as a Write tool in the n8n Workflow Builder MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the n8n Workflow Builder MCP Server MCP server in PolicyLayer and add a rule for create_credential: 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 n8n Workflow Builder MCP Server. Nothing to install.
create_credential 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 create_credential 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 create_credential. 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.
create_credential is provided by the n8n Workflow Builder MCP Server MCP server (makafeli/n8n-workflow-builder). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from n8n Workflow Builder MCP Server, 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.
34 n8n Workflow Builder MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.