nœuds / builtin / ai / aidependencies / tools
MCP Client Tool
Connect an agent to a remote MCP server and let it call the server's tools — with an approval gate on every call.
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Give an AI agent the tools of a remote Model Context Protocol (MCP) server, with your approval before every call.
What it does
Section titled “What it does”MCP Client Tool is a tool provider for an agent, not a step in the flow. It has no output port: you connect it to the Tools slot of a Tools Agent.
When the agent starts, the node connects to Server URL, asks the server which tools it offers, and hands each one to the agent as a separate tool, with the server’s own name, description and arguments. One MCP Client Tool node can therefore add many tools at once. Allowed Tools narrows that list.
Every call is approved first. An approval row appears in the Executions pane, for example “call MCP tool search on mcp.example.com”. It names the tool and server only, never the arguments or your credential. A rejected call never runs, and the model is told you declined. If nobody answers within 2 minutes, the call is rejected.
If the server can’t be reached, rejects the credential or fails to list its tools, this node adds no tools and logs the error, while the agent’s other tools keep working.
When to use it
Section titled “When to use it”- You use a hosted MCP server (a project tracker, a docs search, your own service) and want an AWFlow agent to use its tools.
- You want to reuse existing MCP tools instead of building the same calls with HTTP Request Tool.
Only remote servers reached over the web work. Servers that run as a local program on your computer can’t be started from AWFlow.
Inputs and settings
Section titled “Inputs and settings”| Réglage | Type | Ce que cela fait |
|---|---|---|
| Server URL (obligatoire) | Text | The remote MCP server URL (Streamable HTTP/SSE endpoint) to connect to. |
| Authentication | Credential | The credential to send as the Authorization header on every request. |
| Allowed Tools | List | If set, only remote tools with these names are exposed to the model. Leave empty to expose every tool the server advertises. |
- Server URL is the full endpoint the server’s provider gives you, for example
https://mcp.example.com/mcp. - Allowed Tools takes exact tool names as the server spells them, for example
searchandget_issue. Limiting the list keeps the agent focused and hides tools that change or delete data.
Outputs
Section titled “Outputs”This node has no output port. It plugs into a slot on another node instead of passing items along.
- Tools slot of Tools Agent
Each tool’s result goes back to the model, not to the next node. The agent’s steps output lists the calls it made, and its response holds the final answer.
Dependencies and credentials
Section titled “Dependencies and credentials”- Authentication (connection): optional. See Create a connection.
If the server needs a key, the provider gives you an API key or access token; save it as a Bearer token credential and pick it in Authentication. It is sent as the Authorization header on every request. See Create a credential.
Example workflow
Section titled “Example workflow”- Get Selected Text reads a question you highlighted, with Output field name
text. - MCP Client Tool with Server URL
https://mcp.example.com/mcp, your token in Authentication, and Allowed Tools set tosearch. - Tools Agent with Prompt
Search our docs and answer: {{ $input.text }}, a Chat OpenAI model in Model, and the MCP Client Tool connected to Tools. - Run it and approve “call MCP tool search on mcp.example.com” in the Executions pane. Display Markdown then shows
{{ $input.response }}.
Common issues
Section titled “Common issues”- The agent doesn’t have the server’s tools. The connection or tool listing failed, so the node added none. Open the run’s logs for the “MCP Client Tool: failed to connect” message, then check Server URL and Authentication.
- Only some tools appear. Allowed Tools is filtering them, or a name there doesn’t match the server’s spelling exactly.
- Every call is refused. You rejected it, or nobody approved it within 2 minutes.
- A local server doesn’t work. Only servers with a web address are supported.
Related nodes
Section titled “Related nodes”- Tools Agent: the agent this tool plugs into.
- HTTP Request Tool: let the agent call any API directly.
- Workflow as Tool: turn one of your own workflows into a tool.
- Action Approval: how the approval gate protects you.