Get the schema for a credential type
AI agents call credential_schema to retrieve information from N8n Fabric without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves schema information about credential types, which is informational metadata about how credentials should be structured. It does not create, modify, delete, or execute anything. It has minimal blast radius—an AI agent could misuse it only by gathering information about credential formats, which does not directly expose secrets or enable unauthorized actions. It is purely a Read operation.
From the tool's definition Tool description states 'Get the schema for a credential type' — a retrieval operation with no modification or execution. The name 'credential_schema' and action 'Get' indicate a read-only query for credential metadata/structure.
Attacks that exploit this kind of access
Get the schema for a credential type. It is categorised as a Read tool in the N8n Fabric MCP Server, which means it retrieves data without modifying state.
Register the N8n Fabric MCP server in PolicyLayer and add a rule for credential_schema: 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 Fabric. Nothing to install.
credential_schema is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the credential_schema 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 credential_schema. 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.
credential_schema is provided by the N8n Fabric MCP server (ry-ops/n8n-fabric). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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