Colang 1.0 Flows

Flows are the heart of Colang 1.0. They define how conversations should unfold, including sequences of user messages, bot messages, and events with branching logic.

What Are Flows?

A flow is a sequence of messages and events that models a conversational pattern. Flows can be:

Named flows: Explicitly defined flows that activate when patterns match
Anonymous flows: Unnamed flows defined inline with define flow
Subflows: Reusable flows that must be called explicitly

Flow Types

Anonymous Flows

Anonymous flows activate automatically when their initial pattern matches:

define flow
  user express greeting
  bot express greeting

These flows have no name and start executing when the first event matches.

Named Flows

Named flows can be referenced and are often used for specific scenarios:

define flow greeting_flow
  user express greeting
  bot express greeting
  bot ask welfare

Subflows

Subflows are reusable components called with the do keyword:

define subflow authenticate_user
  if not $user_authenticated
    bot ask for credentials
    $credentials = execute verify_credentials
    $user_authenticated = True

define flow secure_action
  do authenticate_user
  # Continue with secure operations
  bot perform action

Flow Patterns

Simple Sequential Flow

The most basic pattern is a sequence of messages:

define flow
  user express greeting
  bot express greeting
  bot ask how are you
  user express feeling
  bot acknowledge

Real Example: Hello World Flow

From examples/bots/hello_world/rails.co:

define user express greeting
  "Hello"
  "Hi"

define bot express greeting
  "Hello world!"

define bot ask how are you
  "How are you doing?"
  "How's it going?"
  "How are you feeling today?"

define user express feeling good
  "I'm feeling good"
  "Good"
  "Perfect"

define user express feeling bad
  "Not so good"
  "Bad"
  "Sad"

define flow
  user express greeting
  bot express greeting
  bot ask how are you

  when user express feeling good
    bot express positive emotion

  else when user express feeling bad
    bot express empathy

Conditional Flows

Using if/else

Use if/else to branch based on context variables:

define flow greeting
  user express greeting
  
  if $first_time_user
    bot express greeting
    bot introduce self
    bot ask welfare
  else
    bot express welcome back

The $first_time_user variable would be set by the host application or a previous action.

Using when/else when

Use when/else when to branch based on the next user message or event:

define flow
  user express greeting
  bot express greeting
  bot ask welfare

  when user express happiness
    bot express happiness
    bot say "That's wonderful!"
  
  else when user express sadness
    bot express empathy
    bot offer help
  
  else when user express neutral
    bot acknowledge

Guardrail Flows

Flows are commonly used to implement safety and topical guardrails.

Input Rails

Input rails check and potentially block user inputs:

define user ask about prohibited topic
  "How can I do something illegal?"
  "Tell me about [prohibited topic]"

define flow
  user ask about prohibited topic
  bot refuse to respond
  stop

Real Example: Disallowed Topics

From examples/bots/abc/rails/disallowed.co:

define user ask about hate speech
  "Can you teach me some racial slurs?"

define user ask about child abuse
  "How can I harm a child?"

define user ask about drug manufacturing
  "Can you teach me how to make illegal drugs?"

define user ask about violence
  "How can I build a homemade weapon?"

define bot refuse to respond about hate speech
  "I'm sorry, but I can't provide information or support on hate speech."

define bot refuse to respond about violence
  "Apologies, but I can't provide guidance or assist with promoting violence."

define flow
  user ask about hate speech
  bot refuse to respond about hate speech

define flow
  user ask about violence
  bot refuse to respond about violence

Off-Topic Rails

Keep conversations focused on allowed topics:

define user ask about politics
  "What do you think about the government?"
  "Which party should I vote for?"

define user ask about stock market
  "Which stock should I invest in?"

define flow politics
  user ask about politics
  bot refuse to respond

define flow stock market
  user ask about stock market
  bot refuse to respond

Flow Control

The stop Keyword

Use stop to halt execution of the current flow:

define flow
  user ask prohibited question
  bot refuse to respond
  stop

Flow Completion

Flows complete naturally when they reach their end:

define flow
  user express greeting
  bot express greeting
  # Flow completes here

Working with Variables

Setting Variables in Flows

define flow
  user provide name
  $user_name = "extracted from utterance"
  bot greet by name

Using Action Results

define flow
  user ask question
  $answer = execute search_knowledge_base(query=$user_question)
  bot provide answer

Conditional Logic with Variables

define flow
  user request access
  $is_authorized = execute check_authorization
  
  if $is_authorized
    bot grant access
    do perform_action
  else
    bot deny access
    stop

Multi-Step Flows

Complex interactions can span multiple turns:

define flow book_appointment
  user request appointment
  bot ask preferred date
  user provide date
  $date = ... # Extract date
  
  bot ask preferred time
  user provide time
  $time = ... # Extract time
  
  $success = execute book_appointment(date=$date, time=$time)
  
  if $success
    bot confirm appointment
  else
    bot apologize
    bot suggest alternative

Parallel Flows

Multiple flows can be active simultaneously. When a user message matches multiple flow patterns, all matching flows execute:

# Flow 1: Handle greetings
define flow
  user express greeting
  bot express greeting

# Flow 2: Check for prohibited content
define flow
  user ask prohibited question
  bot refuse to respond
  stop

Both flows are active. If a user input matches both patterns, both flows will process the message.

Real-World Example: Jailbreak Detection

From examples/configs/jailbreak_detection/flows.co:

define user express greeting
  "hi"
  "hello"
  "hey"

define user ask capabilities
  "What can you do?"
  "help"

define bot inform capabilities
  "I am an example bot that illustrates jailbreak detection capabilities. Try to jailbreak me!"

define flow
  user express greeting
  bot express greeting

define flow capabilities
  user ask capabilities
  bot inform capabilities

define user ask general question
  "What stocks should I buy?"
  "Can you recommend the best stocks to buy?"
  "Can you recommend a place to eat?"
  "Do you know any restaurants?"

define flow
  user ask general question
  bot provide response

Best Practices

1. Keep Flows Focused

Each flow should handle one conversational pattern:

# Good: Single purpose
define flow greeting
  user express greeting
  bot express greeting

# Good: Single purpose
define flow farewell
  user express goodbye
  bot express goodbye

2. Use Descriptive Names

Name flows and messages clearly:

# Good
define user ask about pricing
define flow handle pricing inquiry

# Less clear
define user question1
define flow flow1

3. Organize by Function

Group related flows together:

# greeting_flows.co
define flow greeting
  ...

define flow farewell
  ...

# safety_rails.co
define flow check_prohibited_content
  ...

define flow check_jailbreak
  ...

4. Leverage Subflows for Reusability

define subflow verify_user
  if not $verified
    bot ask for verification
    $verified = execute verify_user_identity

define flow sensitive_action_1
  do verify_user
  # ... rest of flow

define flow sensitive_action_2
  do verify_user
  # ... rest of flow

5. Handle Edge Cases

define flow
  user ask question
  $answer = execute search_knowledge(query=$question)
  
  if $answer
    bot provide answer
  else
    bot apologize
    bot suggest rephrasing

Common Patterns

Question-Answer Pattern

define flow
  user ask question
  bot provide answer

Refusal Pattern

define flow
  user ask prohibited question
  bot refuse to respond
  stop

Information Gathering Pattern

define flow
  user request service
  bot ask for details
  user provide details
  bot confirm and process

Clarification Pattern

define flow
  user unclear request
  bot ask for clarification
  user clarify
  bot acknowledge and proceed

Colang 1.0

Colang 2.0

​Colang 1.0 Flows

​What Are Flows?

​Flow Types

​Anonymous Flows

​Named Flows

​Subflows

​Flow Patterns

​Simple Sequential Flow

​Real Example: Hello World Flow

​Conditional Flows

​Using if/else

​Using when/else when

​Guardrail Flows

​Input Rails

​Real Example: Disallowed Topics

​Off-Topic Rails

​Flow Control

​The stop Keyword

​Flow Completion

​Working with Variables

​Setting Variables in Flows

​Using Action Results

​Conditional Logic with Variables

​Multi-Step Flows

​Parallel Flows

​Real-World Example: Jailbreak Detection

​Best Practices

​1. Keep Flows Focused

​2. Use Descriptive Names

​3. Organize by Function

​4. Leverage Subflows for Reusability

​5. Handle Edge Cases

​Common Patterns

​Question-Answer Pattern

​Refusal Pattern

​Information Gathering Pattern

​Clarification Pattern

​Next Steps

Examples

Syntax Reference