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eval

eval​

Execute nested workflows with isolated execution contexts.

Input​

input:
  flow_id: "sha256:abc123..."  # Blob ID of stored workflow
  input: <data for nested workflow>
  • flow_id (required): Blob ID of the workflow to execute (must be stored as a blob first)
  • input (required): Input data for the nested workflow

Output​

output:
  result: <output from nested workflow>
  run_id: "uuid-of-execution"
  • result: The result from executing the nested workflow (FlowResult type)
  • run_id: Unique identifier for the nested execution

Example​

steps:
  - id: store_workflow
    component: /builtin/put_blob
    input:
      data:
        $literal:
          schema: https://stepflow.org/schemas/v1/flow.json
          input:
            type: object
            properties:
              data: { type: array }
          steps:
            - id: process
              component: /data/analyze
              input:
                data: { $from: { workflow: input }, path: "data" }
            - id: summarize
              component: /data/summarize
              input:
                analysis: { $from: { step: process } }
          output:
            summary: { $from: { step: summarize } }
      blob_type: "flow"

  - id: run_analysis
    component: /builtin/eval
    input:
      flow_id: { $from: { step: store_workflow }, path: "blob_id" }
      input:
        data: { $from: { step: load_data } }

Use Cases​

  • Workflow Modularity: Break complex workflows into reusable sub-workflows
  • Dynamic Execution: Execute different workflows based on runtime conditions
  • Parallel Sub-workflows: Run multiple independent workflows concurrently
  • Testing: Execute workflows in isolation for testing purposes