State Nodes: The Building Blocks of Reasoning

Workflows in Chain Nodes are composed of specialized state nodes, each representing a distinct step in the "Durable Reasoning" chain. These nodes are executing blocks of logic tied together by a state machine.

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1. Initial State (initial)

The entry point of every workflow run. When a run starts, it begins at the initial state, evaluates its entry logic, and automatically launches the transitions.

• Usage: Used to process starting inputs or setup default blackboard state keys.
• Example:

  - name: INTAKE
    type: initial
    script:
      trigger: '"start"'

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2. Prompt State (prompt)

The core reasoning unit. Executes an AI Agent on your worker task queues. It takes plain-text instructions (with optional Blackboard templating) and parses the agent's LLM response back into blackboard variables.

• Capabilities:
  • Tool Binding: Connects agents to registered MCP servers (SSE or stdio).
  • Templating: Direct double-brace substitution (e.g. ) to inject current blackboard data.
  • Provider Assignment: Configurable per state to target specific active LLM providers (e.g. OpenAI vs Ollama).
• Example:

  - name: ANALYZE
    type: prompt
    agent: classifier-bot
    instructions: "Evaluate the sentiment of {{ customer_message }}. Set sentiment: positive/negative."

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3. Human-in-the-Loop State (hitl)

Suspends automated execution and creates an interactive task in the collaborative Social Inbox.

• Features:
  • Zero Compute Idle: Powered by Temporal, the process completely sleeps (requiring zero memory/CPU) until a human responds.
  • Interactive Forms: Captures input schema fields defined in the workflow's input registry.
  • Assignees: Assign tasks to specific roles (e.g. billing-managers).
• Example:

  - name: MANAGER_APPROVAL
    type: hitl
    assignee: billing-managers
    instructions: "Review mathematical mismatch on invoice total."

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4. Script State (script)

An ultra-fast, zero-latency execution node designed for mathematical evaluations and fast routing decisions. It evaluates expressions using Go's expr package.

• Usage: Modifying variable values or checking conditions instantly.
• Example:

  - name: ASSIGN_QUEUE
    type: script
    script:
      trigger: "urgency == 'critical' ? 'route_priority' : 'route_standard'"
      updates:
        assigned_team: "urgency == 'critical' ? 'tier_3' : 'tier_1'"

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5. Code State (code)

Executes custom Javascript (ES6) inside a secure, fully isolated Goja VM sandbox. Ideal for parsing complex JSON, array manipulation, and advanced math.

• Features:
  • Direct Mutation: Mutate the global bb object directly.
  • Execution Rules: No fetch, require, or timers are exposed, keeping execution safe and sandboxed.
• Example:

  - name: CALCULATE_TAX
    type: code
    code:
      language: javascript
      code: |
        bb.tax = bb.subtotal * 0.19;
        bb.total = bb.subtotal + bb.tax;
        return { trigger: 'done', reasoning: 'Tax computed successfully' };

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6. Wait State (wait)

Halts execution at a gate until a specific logical condition expression evaluates to true or an optional timeout occurs.

• Example:

  - name: WAIT_FOR_PAYMENT
    type: wait
    condition: "blackboard.payment_received == true"
    on_condition: "continue_fulfillment"
    timeout: "24h"
    on_timeout: "cancel_order"

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7. Sub-Process State (subprocess)

Invokes another workflow as a durable child process, allowing you to compose modular, reusable workflows (Skills) together.

• Example:

  - name: RUN_AUDIT
    type: subprocess
    subprocess:
      name: invoice-auditor
      version: 1
      inputs:
        invoice_id: "blackboard.invoice_id"

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8. Emit Event State (emit_event)

Broadcasts a named platform event to the Redis event bus, waking up or signaling other active/waiting workflow runs in the workspace.

• Example:

  - name: SIGNAL_COMPLETED
    type: emit_event
    emit_event:
      name: "order.shipped"
      payload:
        order_id: "blackboard.order_id"

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9. Terminal State (terminal)

Ends execution of the workflow run. The status is set to completed and clean-up operations are executed.

• Example:

  - name: SUCCESS
    type: terminal