Lists all available nodes in the n8n instance. Use this tool BEFORE creating or updating workflows to ensure you only use valid node types. This helps prevent errors caused by using node types that do not exist in the current n8n instance.
AI agents call list_available_nodes to retrieve information from Mcp N8n Builder without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a straightforward informational read operation. It queries the n8n instance to enumerate valid node types. While it provides information that could theoretically be used to craft harmful workflows, the tool itself only retrieves data with no side effects.
From the tool's definition Tool retrieves and lists available nodes from the n8n instance without modifying, creating, or deleting any data. The description states 'Lists all available nodes' which is a query/retrieval operation.
Documented attack patterns abuse exactly the kind of access list_available_nodes gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp N8n Builder, and nothing reaches the server without passing your rules. This is the rule we recommend for list_available_nodes:
{
"version": "1",
"default": "deny",
"tools": {
"list_available_nodes": {}
}
}list_available_nodes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Lists all available nodes in the n8n instance. Use this tool BEFORE creating or updating workflows to ensure you only use valid node types. This helps prevent errors caused by using node types that do not exist in the current n8n instance. It is categorised as a Read tool in the Mcp N8n Builder MCP Server, which means it retrieves data without modifying state.
Register the Mcp N8n Builder MCP server in PolicyLayer and add a rule for list_available_nodes: 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 N8n Builder. Nothing to install.
list_available_nodes 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 list_available_nodes 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 list_available_nodes. 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.
list_available_nodes is provided by the Mcp N8n Builder MCP server (spences10/mcp-n8n-builder). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 Mcp N8n Builder tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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10 Mcp N8n Builder tools catalogued and risk-classified — across an index of 42,500+ MCP servers.