YAML Configuration

For advanced users who prefer code editing or need version-controlled pipeline definitions.

What is YAML View

A code editor for pipelines in the Configuration tab (alongside Flow Editor) that provides direct access to pipeline YAML definitions. Features:

Instant Flow Sync: Changes sync instantly between YAML and Flow views
Syntax Highlighting: Color-coded YAML structure with CodeMirror
Real-time Validation: Immediate error feedback
Find & Replace: Ctrl+F (Windows) or ⌘+F (Mac)
Version Control: Copy/paste YAML for backup or sharing

Schema Structure

Every pipeline has three required top-level sections:

entry_point: <node_id>        # Required
state: {...}                   # Required
nodes: [...]                   # Required

Field	Type	Required	Description
`entry_point`	String	✔️	Starting node ID
`state`	Object	✔️	State variable definitions
`nodes`	Array	✔️	Node configurations

State Configuration

Defines all variables used across the pipeline. Each has a type and optional default value.

State Syntax

state:
  <variable_name>:
    type: <data_type>
    value: <default_value>  # Optional

Default variables like input and messages don’t require initial values—they are populated during pipeline execution.

Data Types:

Type	Example
`string`	`"Hello"`
`number`	`42`, `3.14`
`list`	`[]`, `["a", "b"]`
`JSON`	`{}`, `{"key": "value"}`

Example:

state:
  input:
    type: string
  counter:
    type: number
    value: 0
  qna_list:
    type: list
    value: []
  metadata:
    type: JSON
    value: {}

Use descriptive names (user_query vs q)
Initialize accumulators ('', [], 0)
See States Guide for details

Node Configuration

The nodes array contains all pipeline nodes with common structure plus node-specific fields. Common Fields (all nodes):

Field	Type	Required	Description
`id`	String	✔️	Unique node identifier
`type`	String	✔️	Node type (see overview)
`input`	Array	✔️	State variables to read
`output`	Array	✔️	State variables to write
`transition`	String	Conditional	Next node ID (not needed with `condition`, `decision`, or `END`)

Node-Type-Specific Configurations

Configurations for key node types. See Nodes Overview for the full list of all 11 node types.

1. LLM Node

Calls language models with system/task prompts.

- id: Summarizer
  type: llm
  prompt:
    type: string
    value: ''
  input: [article_text]
  output: [messages]
  structured_output: false
  transition: NextNode
  input_mapping:
    system:
      type: fixed
      value: "You are an expert summarizer"
    task:
      type: fstring
      value: "Summarize: {article_text}"
    chat_history:
      type: fixed
      value: []
  tool_names:              # Optional
    toolkit_name:
      - tool1

Mapping Types: fixed (static), variable (state reference), fstring (template with {var})

2. Agent Node

Executes pre-configured agents.

 - id: Agent 1
    type: agent
    input:
      - input
    output:
      - metadata
    transition: END
    input_mapping:
      task:
        type: fstring
        value: ''
      chat_history:
        type: fixed
        value: []
    tool: Github

3. Code Node

Executes Python in sandbox.

- id: DataProcessor
  type: code
  code:
    type: fixed
    value: |
      # Access state
      input_text = alita_state.get('input')
      
      # Return dict to update state
      {"processed": input_text.upper()}
  input: [input]
  output: [processed_data]
  structured_output: true
  transition: END

Use alita_state.get('var') to access state variables, return dict with structured_output: true

4. Router Node

Template-based routing with Jinja2.

- id: CategoryRouter
  type: router
  default_output: DefaultNode
  routes: [ProcessA, ProcessB, END]
  input: [category]
  condition: |
    {% if category == 'urgent' %}
      ProcessA
    {% elif category == 'normal' %}
      ProcessB
    {% else %}
      END
    {% endif %}

5. Decision Node

LLM-powered routing.

- id: SmartRouter
  type: decision
  input: [user_input]
  output: [classification]
  decision:
    description: |
      Route to SaveNode if user wants to save, 
      otherwise END
    decisional_inputs: [user_input]
    nodes: [SaveNode]
    default_output: END
  tool_names:              # Optional
    toolkit1: [tool_a]

6. State Modifier Node

Transforms state with Jinja2 templates.

- id: IncrementCounter
  type: state_modifier
  template: '{{ index + 1 }}'
  variables_to_clean: []
  input: [index]
  output: [index]
  transition: NextNode

Advanced Example:

- id: AggregateResponse
  type: state_modifier
  template: |
    {{ response_full }} 
    
    ## Question {{index}}
    {{question}} 
    
    ## Answer {{index}} 
    {{messages[-1].content }}
  variables_to_clean: []
  input: [response_full, messages, question, index]
  output: [response_full]
  transition: NextStep

7. HITL Node

Pauses pipeline execution and waits for a human decision (Approve, Edit, or Reject) before continuing.

- id: Review_summary
  type: hitl
  input:
    - summary
  user_message:
    type: fstring             # fixed | fstring | variable
    value: "Please review the following summary and choose an action:\n\n{summary}"
  routes:
    approve: Publish_node     # Route on Approve
    reject: END               # Route on Reject
    edit: Regenerate_node     # Route on Edit
  edit_state_key: summary     # State variable updated when user edits

User Message Types:

Type	Description	Example
`fixed`	Static text shown as-is	`"Please approve to continue."`
`fstring`	Template with `{state_key}` placeholders resolved from state	`"Review draft:\n\n{draft_content}"`
`variable`	Reads the entire message from a named state variable	`review_message`

Only configured routes appear as buttons in the UI — omit routes you don’t need
edit requires edit_state_key to be set; omitting either hides the Edit button
Use END as a route value to terminate the pipeline for that action
HITL nodes do not use transition — routing is handled entirely by routes

Entry Point

Specifies the first node to execute.

entry_point: StartNode

nodes:
  - id: StartNode
    type: llm
    # ...

Must reference existing node ID; only one per pipeline; Router nodes cannot be entry points

Interrupts

Defines pause points for user input. See Nodes Connectors.

interrupt_after:
  - ReviewNode
  - ApprovalCheck

nodes:
  - id: ReviewNode
    type: llm
    transition: NextNode

Human-in-the-loop workflows, review checkpoints, approval gates

Connections

Nodes connect via transition, condition, decision, or routes. See Nodes Connectors. Simple Transition:

- id: Step1
  type: llm
  transition: Step2
  
- id: Step2
  type: code
  transition: END

Router:

nodes:
  - id: CategoryRouter
    type: router
    default_output: DefaultNode
    routes:
      - ProcessA
      - ProcessB
    condition: |
      {% if category == 'urgent' %}
        ProcessA
      {% else %}
        ProcessB
      {% endif %}

Decision:

nodes:
  - id: SmartRouter
    type: decision
    decision:
      description: "Route based on user intent"
      nodes:
        - SaveNode
        - ProcessNode
      default_output: END

HITL Routes:

nodes:
  - id: ReviewStep
    type: hitl
    user_message:
      type: fixed
      value: "Please approve or reject the generated content."
    routes:
      approve: PublishNode
      reject: END
      edit: ReviseNode
    edit_state_key: draft_content

Editor Features

CodeMirror Capabilities:

Syntax highlighting with color-coded structure
Error detection (red underlines for invalid YAML)
Auto-indentation for nested structures
Line numbers for navigation
Find & Replace: Ctrl+F (Windows) / ⌘+F (Mac)

Two-Way Sync: Changes sync instantly between YAML and Flow Editor.

YAML → Flow: Add node in YAML → appears in Flow canvas
Flow → YAML: Add node via Flow + button → YAML updates automatically

Start in Flow for layout → switch to YAML for bulk edits → copy YAML for version control

YAML Guide

Syntax Rules

Indentation (use spaces, not tabs):

✔️ Correct:
nodes:
  - id: Node1
    type: llm
    input:
      - var1

✘ Incorrect (mixed spaces/tabs):
nodes:
  - id: Node1
	type: llm    # Tab used instead of spaces

Strings with Special Characters

✔️ Correct:
template: '{{ index + 1 }}'
description: "Route: urgent"
value: |
  Multi-line
  content

✘ Wrong:
template: {{ index + 1 }}
description: Route: urgent

Lists (use block style):

✔️ Correct:
input: [var1, var2]
routes:
  - NodeA
  - NodeB

✘ Avoid inline for readability

Booleans/Null (lowercase):

✔️ Correct:
structured_output: true
structured_output: false
value: null

✘ Wrong:
structured_output: True
value: None

Common Errors

Missing Quotes:

✘ condition: {% if approved %}
✔️ condition: '{% if approved %}'

Undefined Node:

✘ transition: NonExistentNode
✔️ Ensure node exists in nodes array

Invalid Type:

✘ type: invalid_type
✔️ type: llm  # Use: llm, agent, toolkit, mcp, code, custom, router, decision, hitl, state_modifier, printer

Missing Fields:

✘ nodes:
     - id: Node1
       type: llm
✔️ Add: input, output, transition

Validation Checklist

Before saving:

Entry point references existing node ID
All node IDs are unique
All transitions reference existing nodes or END
State variables in nodes are defined in state
Input/output arrays use valid variable names
Node-specific fields complete (e.g., LLM has input_mapping)
No YAML syntax errors (red underlines)
Indentation uses spaces
Quotes around special characters (:, {, %)

Best Practices

Use Descriptive IDs

✔️ - id: FetchUserData
✘ - id: Node1

Initialize Defaults

✔️ counter: {type: number, value: 0}
✘ counter: {type: number}

Multi-Line Templates

✔️ template: |
     {% if condition %}NodeA{% else %}NodeB{% endif %}
✘ template: '{% if condition %}NodeA{% else %}NodeB{% endif %}'

Group Nodes with Comments

nodes:
  # Data Loading
  - id: LoadData
  # Processing
  - id: ProcessData

Don't Hardcode Secrets

✘ api_key: {type: fixed, value: "sk-123"}
✔️ Use Credentials instead

Avoid Unreachable Nodes

✘ - id: Node1
     transition: Node3
   - id: Node2  # Unreachable

Always Terminate

✔️ - id: FinalNode
     transition: END

Workflow Tips

Start Visual, Refine in Code: Use Flow Editor for layout → YAML for bulk edits
Bulk Updates: Find/replace to update toolkit names, node IDs
Test Incrementally: Add one node at a time, run pipeline after each
Version Control: Copy YAML to files, commit to git
Use Comments:
# Step 1: Load data - id: LoadData

Flow Editor - Visual pipeline building
States - State variable design
Nodes Overview - All node types
Nodes Connectors - Connection patterns
Entry Point - Entry point rules
Interaction Nodes - LLM, Agent
Execution Nodes - Toolkit, MCP, Code, Custom nodes
Control Flow Nodes - Router, Decision, HITL
Utility Nodes - State Modifier, Printer

Chat & Conversations

Indexing

Agents & Pipelines

Credentials & Toolkits

Entity Management

What is YAML View

Schema Structure

State Configuration

State Syntax

Node Configuration

Node-Type-Specific Configurations

1. LLM Node

2. Agent Node

3. Code Node

4. Router Node

5. Decision Node

6. State Modifier Node

7. HITL Node

Entry Point

Interrupts

Connections

Editor Features

YAML Guide

Syntax Rules

Strings with Special Characters

Common Errors

Validation Checklist

Best Practices

​What is YAML View

​Schema Structure

​State Configuration

​State Syntax

​Node Configuration

​Node-Type-Specific Configurations

​1. LLM Node

​2. Agent Node

​3. Code Node

​4. Router Node

​5. Decision Node

​6. State Modifier Node

​7. HITL Node

​Entry Point

​Interrupts

​Connections

​Editor Features

​YAML Guide

​Syntax Rules

​Strings with Special Characters

​Common Errors

​Validation Checklist

​Best Practices

What is YAML View

Schema Structure

State Configuration

State Syntax

Node Configuration

Node-Type-Specific Configurations

1. LLM Node

2. Agent Node

3. Code Node

4. Router Node

5. Decision Node

6. State Modifier Node

7. HITL Node

Entry Point

Interrupts

Connections

Editor Features

YAML Guide

Syntax Rules

Strings with Special Characters

Common Errors

Validation Checklist

Best Practices