initial docs for standalone mcp client node (#3975)

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>
Co-authored-by: Kartik Balasubramanian <22399046+HumanistSerif@users.noreply.github.com>

Author: 3 people

docs/integrations/builtin/core-nodes/n8n-nodes-langchain.mcpClient.md

@@ -0,0 +1,52 @@
+---
+title: MCP Client node documentation
+description: Learn how to use the MCP Client node in n8n. Follow technical documentation to integrate MCP Client node into your workflows.
+contentType: [integration, reference]
+---
+
+# MCP Client node
+
+The MCP Client node is a [Model Context Protocol (MCP)](https://modelcontextprotocol.io/introduction) client that allows you to use the tools that are exposed by an external MCP server.
+
+You can use the MCP Client node to use MCP tools as regular steps in a workflow.
+
+If you want to use MCP tools as tools for an AI Agent, use the [MCP Client Tool node](/integrations/builtin/cluster-nodes/sub-nodes/n8n-nodes-langchain.toolmcp.md) instead.
+
+///  note  | Credentials
+The MCP Client node supports [Bearer](/integrations/builtin/credentials/httprequest.md#using-bearer-auth), generic [header](/integrations/builtin/credentials/httprequest.md#using-header-auth), and [OAuth2](/integrations/builtin/credentials/httprequest.md#using-oauth2) authentication methods.
+///
+
+## Node parameters
+
+Configure the node with the following parameters.
+
+* **Server Transport**: The transport protocol used by the MCP Server endpoint you want to connect to.
+* **MCP Endpoint URL**: The URL of the external MCP Server. For example, `https://mcp.notion.com/mcp`.
+* **Authentication**: The authentication method for authentication to your MCP server. The MCP Client node supports [bearer](/integrations/builtin/credentials/httprequest.md#using-bearer-auth), generic [header](/integrations/builtin/credentials/httprequest.md#using-header-auth), and [OAuth2](/integrations/builtin/credentials/httprequest.md#using-oauth2) authentication. Select **None** to attempt to connect without authentication.
+* **Tool**: Select the tool to use in the node. The list of tools is automatically fetched from the external MCP server.
+* **Input Mode**: 
+	* **Manual**: Specify each tool parameter manually.
+	* **JSON**: Specify tool parameters as a JSON object. Use this mode for tools with nested parameters.
+
+## Options
+
+* **Convert to Binary**: Whether to convert images and audio to binary data. If false, images and audio are returned as base64 encoded strings.
+* **Timeout**: Time in milliseconds to wait for tool calls to finish.
+
+## Templates and examples
+
+<!-- see https://www.notion.so/n8n/Pull-in-templates-for-the-integrations-pages-37c716837b804d30a33b47475f6e3780 -->
+[[ templatesWidget(page.title, 'mcp-client') ]]
+
+## Related resources
+
+To use MCP tools with AI Agents, n8n has the [MCP Client Tool node](/integrations/builtin/cluster-nodes/sub-nodes/n8n-nodes-langchain.toolmcp.md).
+
+n8n also has an [MCP Server Trigger](/integrations/builtin/core-nodes/n8n-nodes-langchain.mcptrigger.md) node that allows you to expose n8n tools to external AI Agents.
+
+Refer to the [MCP documentation](https://modelcontextprotocol.io/introduction) and [MCP specification](https://modelcontextprotocol.io/specification/) for more details about the protocol, servers, and clients.
+
+--8<-- "_snippets/integrations/builtin/cluster-nodes/tools-link.md"
+
+--8<-- "_snippets/integrations/builtin/cluster-nodes/langchain-overview-link.md"
+

nav.yml

@@ -229,6 +229,7 @@ nav:
         - integrations/builtin/core-nodes/n8n-nodes-base.splitinbatches.md
         - Manual Trigger: integrations/builtin/core-nodes/n8n-nodes-base.manualworkflowtrigger.md
         - integrations/builtin/core-nodes/n8n-nodes-base.markdown.md
+        - MCP Client: integrations/builtin/core-nodes/n8n-nodes-langchain.mcpClient.md
         - MCP Server Trigger: integrations/builtin/core-nodes/n8n-nodes-langchain.mcptrigger.md
         - integrations/builtin/core-nodes/n8n-nodes-base.merge.md
         - integrations/builtin/core-nodes/n8n-nodes-base.n8n.md