​ To learn more, see the sources I considered: [[1] Flex Mode](https://docs.retellai.com/build/conversation-flow/flex-mode) [[2] Flex Mode, Advanced Warm Transfer, 60+ languages, and more.](https://www.retellai.com/changelog/flex-mode-advanced-warm-transfer-60-languages-and-more) ​

### Answer Unfortunately, using equation-based conditions (like checking

{{session_duration}}

) for transitions in Flex Mode is not recommended. The documentation explicitly states: > "Only use Prompt edge, avoid using Equation edge as LLM is really bad at interpret equation conditions. You might see very weird behaviors." [(1) ]() In Flex Mode, all nodes get compiled into a single structured prompt, and the agent navigates tasks dynamically based on natural language conditions rather than programmatic equation checks. Recommended approach: Instead of relying on

{{session_duration}}

with an equation edge, you should: 1. Use a Prompt edge with explicit, observable conditions written in natural language 2. Write crisp, clear transition instructions in your node prompts that describe when to move to the next task If you need strict, time-based sequencing, consider keeping that portion of your flow in rigid mode (standard conversation flow) rather than Flex Mode, since Flex Mode is designed for flexible navigation where customers may jump between topics. [(2) ]()

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

Thanks for the follow-up, @Legend. I'll get back to you soon.

versation flow components typically work?

​ To learn more, see the sources I considered: [[1] Flex Mode](https://docs.retellai.com/build/conversation-flow/flex-mode) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer That approach is problematic if you're using Flex Mode. The documentation explicitly warns against using equation-style conditions: > "Only use Prompt edge, avoid using Equation edge as LLM is really bad at interpret equation conditions. You might see very weird behaviors." [(1) ]() The issue with your prompt: Your condition

{{session_duration}} is greater or equal to 30 seconds

is essentially an equation-based condition written in natural language. In Flex Mode, the LLM interprets all node instructions dynamically, and it struggles to reliably evaluate numeric comparisons like this. Recommended approach: If you need time-based transitions, keep that logic outside of Flex Mode in the standard conversation flow portion, where you can use a proper Equation Edge that evaluates

{{session_duration}} >= 30

programmatically. For the Flex Mode component itself, write node instructions in a concise manner focused on conversational tasks, and use Prompt edges with crisp, observable conditions based on what the caller says or *does*—not on numeric variable evaluations. If you absolutely need this behavior within Flex Mode, consider having a separate standard flow node with an Equation Edge that checks the session duration and then transitions to your target node outside the Flex Mode context.

​ To learn more, see the sources I considered: [[1] Flex Mode](https://docs.retellai.com/build/conversation-flow/flex-mode) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer For a Global Node in rigid mode, you need to set a condition for when the global node should be transitioned to. [(1) ]() The issue is that your condition mixes an equation-style check (

{{session_duration}} is greater or equal to 30 seconds

) with a conversational state check (

caller has not been informed...

) . Global node conditions work best when they describe observable conversational triggers. What to try: 1. Use a proper Equation Edge for the numeric comparison rather than writing it as natural language in the transition condition. The condition field for global nodes expects a prompt-style description of when the transition should happen based on conversation context. 2. Separate the logic: - Create an Equation Edge that checks

{{session_duration}} >= 30

- Use the global node's condition to describe the conversational trigger (e.g., "When the agent needs to inform the caller about call duration limits") 3. Add transition finetune examples to help the model understand when to trigger the global node. You can add example conversations showing when the agent should and should not jump to the global node. [(2) ]() Debugging steps: - Review your transition conditions to ensure they precisely match your intended triggers [(3) ]() - Consider adding finetune examples to help the model understand your expectations - Check if the condition is too complex—try breaking it down into simpler conditions I don't have explicit documentation showing the exact syntax for combining equation checks with global node conditions in rigid mode. You may want to test using a pure Equation Edge for the time check separately.

​ To learn more, see the sources I considered: [[1] Global Node](https://docs.retellai.com/build/conversation-flow/global-node) [[2] Platform Changelogs | Retell AI](https://www.retellai.com/changelog) [[3] Debug guide](https://docs.retellai.com/build/conversation-flow/debug-guide) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer --- For a global node, you set a condition that describes when the node should be transitioned to from anywhere in the call. [(1) ]() The challenge with your use case is that the agent doesn't inherently "know" about session duration limits unless you explicitly tell it. The global node condition should describe an observable conversational trigger, not an equation check. Recommended approach: Since global node conditions are evaluated based on conversation context (not programmatic variable checks) , you have two options: 1. Don't use a global node for this — Instead, use a standard node with an Equation Edge that checks

{{session_duration}} >= 240

(or whatever threshold) . This equation edge can then transition to a conversation node that informs the caller. Equation edges are evaluated programmatically, not by the LLM. 2. If you must use a global node, write the condition to match something the caller says or does, not a time-based trigger. For example: -

When the caller asks how much time is left on the call

But this won't help you proactively warn them. The core issue: Global node conditions check the conversation context to determine when to transition. They don't evaluate

{{session_duration}}

as a numeric comparison—that requires an Equation Edge outside the global node mechanism. For time-based proactive behavior, use an Equation Edge on a standard node, not a global node condition.

​ To learn more, see the sources I considered: [[1] Global Node](https://docs.retellai.com/build/conversation-flow/global-node) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer In a rigid conversation flow with Flex Mode components, you would place the equation condition on a Conversation Node that sits outside your Flex Mode component. [(1) ]() Where to define it: For Conversation Nodes, you can define conditions to transition out of the node. How to structure it: 1. Create a standard Conversation Node in your rigid flow (outside the Flex component) 2. Click on that node and click the "+" button to add a transition condition 3. Choose to add an Equation transition condition 4. In the equation editor, add your condition:

{{session_duration}} >= 240

5. Connect this equation edge to your target node (the one that warns the caller about call duration) Example equation syntax from the documentation:

- {{current_time}} > 9 AND {{current_time}} < 18

Note that comparison operators like

>=

,

>

,

<

require numerical input and will evaluate to false if the input is not a number. Important: You can only use variables that are passed in as dynamic variables for equation conditions. Since

{{session_duration}}

is a built-in dynamic variable, this should work in rigid mode.

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

​ To learn more, see the sources I considered: [[1] Step 3: Add transition conditions](https://docs.retellai.com/build/conversation-flow/transition-condition) ​

### Answer Yes, that matters. The equation edge needs to be connected to a destination node for the transition to actually occur. In conversation flow, edges are connections between nodes that define transition logic. [(1) ]() When you set up an equation condition like

{{session_duration}} >= 30

, you're defining when to transition—but you also need to define where to transition to by connecting that edge to another node. What to do: 1. Connect the equation edge from your component to the target node you want to transition to (the node that warns the caller about call duration) 2. Make sure the target node exists outside your Flex component in the rigid portion of your flow Without a connected destination, the condition may evaluate as true but the agent has nowhere to go, so no transition happens.

​ To learn more, see the sources I considered: [[1] Conversation Flow Overview](https://docs.retellai.com/build/conversation-flow/overview) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Yes, not linking the Exit Component node properly is likely the issue. The documentation explicitly states: > "What if I did not link the Exit node properly in a component? It will stay stuck inside the component and cannot transition out." [(1) ]() What you need to do: 1. Inside your component, make sure you have an "Exit Component" end node 2. Link your component's internal nodes to that Exit Component node so the flow can properly exit 3. The Exit Component node hands control back to the main flow, where your equation edge on the component node can then transition to the next step Without a properly linked Exit node inside the component, the conversation will stay stuck inside the component and cannot transition out—even if your equation condition evaluates to true on the outside.

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

​ To learn more, see the sources I considered: [[1] Components](https://docs.retellai.com/build/conversation-flow/components) ​

Thanks for the follow-up, @Legend. I'll get back to you soon.

​ To learn more, see the sources I considered: [[1] Components](https://docs.retellai.com/build/conversation-flow/components) [[2] Step 3: Add transition conditions](https://docs.retellai.com/build/conversation-flow/transition-condition) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer You're right—there's no conversational trigger for a time-based interruption. The documentation confirms that Exit nodes inside a Component hand control back to the main flow. [(1) ]() The solution: Don't rely on the Exit Component node for your time-based transition. Instead: 1. Keep the equation edge on the Component node itself (in your rigid flow outside the component) with

{{session_duration}} >= 30

2. Connect that equation edge directly to your warning node The equation edge on the Component node in rigid mode should evaluate programmatically and interrupt/transition out of the component when the condition is met—regardless of what's happening inside the Flex component. For the Exit Component node inside your Flex component: Use a generic conversational condition like: -

When the conversation has naturally concluded

-

When the caller indicates they are done

This handles normal exits. Your time-based equation edge on the outside of the component should handle the forced mid-conversation transition. If this still isn't working, the issue may be that equation edges on Component nodes don't interrupt active Flex conversations mid-flow. I don't have explicit documentation confirming whether equation edges can forcibly interrupt a Flex component mid-conversation. You may need to reach out for clarification: - [Contact Sales]() - [Retell AI GitHub]()

​ To learn more, see the sources I considered: [[1] Components](https://docs.retellai.com/build/conversation-flow/components) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer --- Based on the documentation, there's a critical detail about equation conditions: you can only use variables that are passed in as dynamic variables for equation conditions. [(1) ]() The documentation states: > "Note: You can only use variables that are passed in as dynamic variables for equation conditions. If you need to use information extracted by the LLM (such as information learned during the call) , you can use prompt conditions." The issue:

{{session_duration}}

may not be available as a dynamic variable that equation conditions can evaluate unless it's explicitly passed in or configured as a default dynamic variable. Things to check: 1. Verify

session_duration

is defined — Check if

session_duration

is set up in your

default_dynamic_variables

configuration or passed in when the call starts. [(2) ]() 2. Transition timing — For Conversation Nodes, transitions happen "when user is done speaking" or "when Skip Response is enabled and agent finishes speaking." [(3) ]() The equation won't evaluate continuously—it evaluates at transition points. 3. Numerical input requirement — The comparison operators require numerical input and "will always evaluate to false if the input is not a number." [(1) ]() I don't have explicit documentation confirming that

session_duration

is automatically available as a dynamic variable for equation conditions. You may need to verify this with support: - [Contact Sales]() - [Retell AI GitHub]()

​ To learn more, see the sources I considered: [[1] Step 3: Add transition conditions](https://docs.retellai.com/build/conversation-flow/transition-condition) [[2] List Conversation Flows](https://docs.retellai.com/api-references/list-conversation-flows) [[3] Conversation Node](https://docs.retellai.com/build/conversation-flow/conversation-node) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Yes, transition priority exists. The documentation states: [(1) ]() All equation conditions are evaluated first, and then the prompt conditions are evaluated. Additionally, equation conditions are evaluated from top to bottom, and the flow travels on the first condition that evaluates to true. How to change order: You can change the order of equations by clicking on the 6 dots on the left of the equation and dragging it up or down. You can also change "ANY" to "ALL" to force all equations to be true instead of just one. Summary of priority: 1. Equation conditions evaluate first (top to bottom) 2. Prompt conditions evaluate after all equation conditions 3. First condition that evaluates to true triggers the transition

​ To learn more, see the sources I considered: [[1] Step 3: Add transition conditions](https://docs.retellai.com/build/conversation-flow/transition-condition) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.