> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unstructured.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom workflow DAG nodes

If `WorkflowType` is set to `CUSTOM` (for the Python SDK), or if `workflow_type` is set to `custom` (for `curl` or Postman), you must also specify the settings for the workflow's
directed acyclic graph (DAG) nodes. These nodes' settings are specified in the `workflow_nodes` array.

* A **Source** node is automatically created when you specify the `source_id` value outside of the\
  `workflow_nodes` array.

* A **Destination** node is automatically created when you specify the `destination_id` value outside of the
  `workflow_nodes` array.

* You can specify [Partitioner](/api-reference/workflow/nodes/partitioner/partitioner), [Enrichment](/api-reference/workflow/nodes/enrichment/enrichment),
  [Chunker](/api-reference/workflow/nodes/chunker/chunker), and [Embedder](/api-reference/workflow/nodes/embedder/embedder) nodes.

  <Warning>
    Unstructured can potentially generate image summary descriptions, table summary descriptions, table-to-HTML output, and generative OCR optimizations, only for workflows that are configured as follows:

    * With a **Partitioner** node set to use the **Auto** or **High Res** partitioning strategy, and an image summary description node, table summary description node, table-to-HTML output node, or generative OCR optimization node is added.
    * With a **Partitioner** node set to use the **VLM** partitioning strategy. No image summary description node, table summary description node, table-to-HTML output node, or generative OCR optimization node is needed (or allowed).

    Even with these configurations, Unstructured actually generates image summary descriptions, table summary descriptions, and table-to-HTML output only for files that contain images or tables and are also eligible
    for processing with the following partitioning strategies:

    * **High Res**, when the workflow's **Partitioner** node is set to use **Auto** or **High Res**.
    * **VLM** or **High Res**, when the workflow's **Partitioner** node is set to use **VLM**.

    Unstructured never generates image summary descriptions, table summary descriptions, or table-to-HTML output for workflows that are configured as follows:

    * With a **Partitioner** node set to use the **Fast** partitioning strategy.
    * With a **Partitioner** node set to use the **Auto**, **High Res**, or **VLM** partitioning strategy, for all files that Unstructured encounters that do not contain images or tables.

    Unstructured never produces generative OCR optimizations for workflows with a **Partitioner** node set to use the **Fast** partitioning strategy.
  </Warning>

* The order of the nodes in the `workflow_nodes` array will be the same order that these nodes appear in the DAG,
  with the first node in the array added directly after the **Source** node. The **Destination** node
  follows the last node in the array.

* Be sure to specify nodes in the allowed order. The following DAG placements are all allowed:

```mermaid theme={null}
flowchart LR
    Partitioner
```

```mermaid theme={null}
flowchart LR
    Partitioner-->Chunker
```

```mermaid theme={null}
flowchart LR
    Partitioner-->Chunker-->Embedder
```

```mermaid theme={null}
flowchart LR
    Partitioner-->Enrichment-->Chunker
```

```mermaid theme={null}
flowchart LR
    Partitioner-->Enrichment-->Chunker-->Embedder
```

<Note>
  For workflows that use **Chunker** and enrichment nodes together, the **Chunker** node should be placed after all enrichment nodes. Placing the
  **Chunker** node before any enrichment nodes could cause incomplete or no enrichment results to be generated.
</Note>