core-sdk

Create a WorkflowBuilder, add nodes with workflow.add_node("NodeName", "id", {config}), connect them with 4-parameter add_connection calls, then execute with runtime.execute(workflow.build()). Never call workflow.execute(runtime).

Use the 4-parameter syntax: workflow.add_connection(source_id, source_output, target_id, target_input). Dot notation like "result.metrics.accuracy" extracts nested fields, and one output can fan out to multiple targets.

Use AsyncLocalRuntime for Docker and FastAPI async contexts, and LocalRuntime for CLI scripts and synchronous code. Using LocalRuntime inside Docker causes hangs, so AsyncLocalRuntime is mandatory there.

Use one of three methods: static node configuration at build time, dynamic connections from other nodes, or runtime parameters passed to execute(). Node-specific runtime parameters are automatically unwrapped and isolated per node.

Cyclic workflows are a planned feature that is not yet implemented in the SDK. Until release, use alternative patterns such as retry logic or manual loops instead of cycle-based iteration.

Common causes are using the deprecated 3-parameter connection syntax, mismatched node IDs, or wrong port names such as "output" instead of "data" for CSVReaderNode. Verify node IDs match exactly and check each node's documented ports.