Connect sources and tools to a block

Some blocks in your organization have a Contextual ports section in their configuration panel. Use it to connect data sources or MCP tools. The connected block prepares its data before the block that uses it runs.

The connection type and fields depend on the block you choose from the palette.

Connect data sources

1. Add the block that will use your sources and connect it to the path from Start.
2. Add a Data Sources block to the canvas.
3. In that block, choose an Embedding model, then one or more compatible Data sources.
4. Select the block that will use the sources.
5. In Contextual ports, use Connect block to select the Data Sources block.
6. Fill in the other fields, connect the block’s outputs, and save.

Connect sources

100 %

• After success
• After failure
• Source or tool connection

Drag to move. Use + / − to zoom, arrow keys to move, and Home to reset.

The diagram distinguishes the main path from the source connection. The Data Sources block stays outside the main path: it is prepared before the block it is connected to.

One connection, several sources

A Data sources connection accepts one provider block. That block can contain several sources compatible with the selected embedding model.

Data Sources prepares the selection and its parameters. Searching is performed by the block or tool that uses those sources. See the block reference for available fields and outputs.

Connect MCP tools

1. Add the block that will use the tools and connect it to the main path.
2. Add an MCP - List tools block to the canvas.
3. Configure its MCP servers: name, URL, headers, and metadata when needed.
4. Click Get tools and select the tools you need.
5. Select the block that will use the tools.
6. In Contextual ports, use Connect block or Connect blocks, depending on the available option.
7. Fill in the other fields, connect the block’s outputs, and save.

Connect MCP tools

100 %

• After success
• After failure
• Source or tool connection

Drag to move. Use + / − to zoom, arrow keys to move, and Home to reset.

One MCP - List tools block can contain several servers. When the block using the tools allows multiple connections, you can also connect several tool-list blocks to it.

The list makes tools available. Calls are then executed by the appropriate blocks in the path. To build this path one block at a time, see the MCP agent example.

Why is my block missing from the selection?

The provider must:

• supply the data type expected by the selected block;
• remain outside the main path, with no incoming or outgoing links, including a link from Start;
• be available for this connection, without already being connected to another block.

Remove its links to the main path, then open the selection again. Compatible providers are suggested automatically. Once connected, the provider no longer displays the usual main-path outputs.

If the panel indicates that a connection is required, connect a provider before testing. If it is optional, check that the block gives the expected answer without a provider.

Check the configuration

• The embedding model can be selected and the sources are compatible.
• The source selection was checked after any model change.
• MCP servers are accessible and the required tools were fetched.
• Providers are connected to the correct blocks.
• Main-path outputs are connected.
• The workflow was saved and tested in Semantics Chat.