Actions7
Overview
This node acts as a client interface to an MCP (Model Context Protocol) server, enabling interaction with various MCP resources and tools. It supports multiple connection types to communicate with the MCP server, including command line (STDIO), HTTP streamable protocol, and deprecated Server-Sent Events (SSE).
The "List Tools" operation specifically retrieves the list of available tools from the MCP server. Each tool includes its name, description, and input schema, allowing users to understand what tools are accessible and how to use them.
Common scenarios:
- Discovering which tools are available on an MCP server before executing any.
- Dynamically generating UI elements or workflows based on available tools.
- Integrating MCP tools into automated pipelines by first listing and selecting appropriate tools.
Example:
A user wants to automate a workflow that uses specific MCP tools. They first use this node with the "List Tools" operation to fetch all tools and their input requirements, then configure subsequent nodes to execute selected tools with proper parameters.
Properties
| Name | Meaning |
|---|---|
| Connection Type | Choose the transport type to connect to MCP server. Options: - Command Line (STDIO) - Server-Sent Events (SSE) (Deprecated) - HTTP Streamable (recommended for real-time communication) |
Output
The output JSON contains a tools field which is an array of objects. Each object represents a tool with the following structure:
name: The tool's name (string).description: A textual description of what the tool does (string).schema: A JSON Schema representation of the tool's input parameters, describing expected inputs and their types.
This structured output allows downstream nodes or users to programmatically inspect tool capabilities and prepare valid inputs.
The node does not output binary data.
Dependencies
- Requires connectivity to an MCP server via one of the supported transports:
- Command Line interface (STDIO) with a configured command and environment.
- HTTP Streamable protocol with URL endpoints and optional headers.
- Deprecated SSE transport (not recommended).
- Requires credentials corresponding to the chosen connection type, such as API keys or command configurations.
- Uses external MCP SDK packages for client communication and schema handling.
- Environment variables may be used to augment command-line environment settings.
Troubleshooting
- No tools found: If the MCP server returns no tools, the node throws an error indicating no tools were found. Verify the MCP server has tools registered and the connection is correct.
- Connection errors: Errors during transport creation or connection (e.g., invalid URLs, missing credentials) will cause failures. Check credential configuration and network accessibility.
- Invalid tool schemas: If the MCP server returns malformed input schemas, the node might fail to parse them properly.
- JSON parsing errors: When executing tools (not in this operation), invalid JSON parameters can cause errors. Ensure JSON inputs are well-formed.
- Deprecated SSE usage: Using SSE transport is deprecated; prefer HTTP Streamable for better support and stability.