Workflow Steps

Workflows are built from four step types. Each step receives the current state and can update it for the next step.

Step Types Overview

Step	Purpose
`AgentStep`	Run an agent; optionally map state to input via `inputFrom`.
`FunctionStep`	Custom logic; `run(state, ctx)` returns partial state update.
`ConditionStep`	Branch: if `condition(state)` then run nested steps.
`ParallelStep`	Run multiple steps concurrently; merge results.

AgentStep

Runs an agent. Use inputFrom to derive the agent’s input from state.

interface AgentStep<TState> {
  name: string;
  agent: Agent;
  inputFrom?: (state: TState) => string;
}

string

required

Step identifier. Used in stepResults and logs.

Agent

required

The agent to run.

(state) => string

Maps state to the agent’s input string. If omitted, the full state is JSON-stringified. Agent output is stored as state[stepName + “_output”].

Example

{
  name: "research",
  agent: researcher,
  inputFrom: (state) => `Research: ${state.topic}`,
}

FunctionStep

Runs custom logic. Return a partial state object to merge into the workflow state.

interface FunctionStep<TState> {
  name: string;
  run: (state: TState, ctx: RunContext) => Promise<Partial<TState>>;
}

string

required

Step identifier.

(state, ctx) => Promise<Partial<TState>>

required

Async function. Receives current state and RunContext. Return partial state to merge.

Example

{
  name: "validate",
  run: async (state, ctx) => {
    if (!state.topic?.trim()) {
      throw new Error("Topic is required");
    }
    return { validated: true };
  },
}

ConditionStep

Branches based on a condition. Runs nested steps only when condition(state) is true.

interface ConditionStep<TState> {
  name: string;
  condition: (state: TState) => boolean;
  steps: StepDef<TState>[];
}

string

required

Step identifier.

(state) => boolean

required

Predicate. If true, nested steps run; otherwise they are skipped.

StepDef<TState>[]

required

Nested steps to run when condition is true.

Example

{
  name: "maybe-review",
  condition: (state) => state.needsReview === true,
  steps: [
    {
      name: "review",
      agent: reviewer,
      inputFrom: (state) => `Review: ${state.draft}`,
    },
  ],
}

ParallelStep

Runs multiple steps concurrently. Results are merged into state.

interface ParallelStep<TState> {
  name: string;
  parallel: StepDef<TState>[];
}

string

required

Step identifier.

StepDef<TState>[]

required

Steps to run in parallel. All must complete before the workflow continues.

Example

{
  name: "parallel-analysis",
  parallel: [
    { name: "tech", agent: techAnalyst, inputFrom: (s) => s.proposal },
    { name: "legal", agent: legalAnalyst, inputFrom: (s) => s.proposal },
    { name: "finance", agent: financeAnalyst, inputFrom: (s) => s.proposal },
  ],
}

​Workflow Steps

​Step Types Overview

​AgentStep

​Example

​FunctionStep

​Example

​ConditionStep

​Example

​ParallelStep

​Example

​Full Example

Workflow Steps

Step Types Overview

AgentStep

Example

FunctionStep

Example

ConditionStep

Example

ParallelStep

Example

Full Example