Control when a Retell conversation flow agent moves between nodes: prompt conditions evaluated by the LLM, deterministic equation conditions, and else edges.
Transition conditions decide whether and where the agent moves next. Each edge out of a node pairs a condition with a destination: when the condition is met, the agent transitions to that node. This is where you get the most control over a flow, and where careful testing pays off most.
Prompt: A natural-language condition evaluated by the LLM against the conversation.
Equation: A deterministic comparison over dynamic variables — no LLM involved.
Example prompt conditions:
User said something about booking a meeting
User said something about cancelling a meeting
User claims to be over 18
User said they lived in New York or Los Angeles
Example equation conditions:
- {{user_age}} > 18- {{current_time}} > 9 AND {{current_time}} < 18- {{user_location}} == "New York"- {{user_location}} != "New York"- "New York, Los Angeles" CONTAINS {{user_location}}- {{user_age}} < 18 OR {{user_location}} == "New York"- {{name}} exists
Equation conditions can only reference dynamic variables. For information the agent learns during the call, either use a prompt condition or first capture the value with an extract DV node and branch on it afterwards.
Else edge: The fallback. It fires when no other condition matches, so the flow never gets stuck. Use it deliberately — on a node with an else edge, any user turn that matches nothing else moves through it.
Always edge: Transitions unconditionally as soon as the user responds, skipping condition evaluation entirely. Useful when the node just needs one reply (e.g. an acknowledgment) before moving on.
Skip Response edge: Created when the node’s Skip Response setting is on. The node transitions once the agent finishes speaking, without waiting for the user — good for disclaimers or hand-off lines.
When a transition check runs, conditions are evaluated in this order:
Always edge — if the node has one, the agent transitions through it right after the user responds. Nothing else is checked.
Equation conditions — evaluated deterministically before any prompt condition. Among equation edges, evaluation runs top to bottom and the first condition that evaluates true wins.
Prompt conditions — if no equation matched, the LLM evaluates all prompt conditions together, alongside any global node entry conditions, and picks the single best match — or none.
Else edge — if nothing matched and the node has an else edge, the agent transitions through it.
Stay — otherwise the agent stays in the current node and keeps the conversation going.
Click the node, then click the + button to add a transition condition. Choose Prompt or Equation.
Adding a transition condition from the node's edge list.
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Write the condition
For a prompt condition, type the condition text directly on the edge.For an equation condition, the equation editor opens. Click Add equation to add rows, the trash icon to delete one, and switch ANY to ALL to require every equation to be true.
The equation editor with ANY/ALL and per-row controls.
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Reorder equations
Drag the six-dot handle on the left of an equation to move it up or down. Order matters: the first equation condition that evaluates true wins.
The LLM sees the current node’s instruction while evaluating conditions, but each condition should stand on its own — describe what the user said or the state reached, without leaning on the instruction text:
When user indicates they want to book a meeting
User declines the invitation
User responds to question of their age
For function nodes, you can reference the result: CRM lookup returned successful result
To keep the agent from getting stuck, cover every case you expect at that point in the conversation. General cases (like objection handling) can live on global nodes, so node-level conditions only need to cover what’s specific to that step.For equation conditions, cover every branch the dynamic variables can take. For example, to treat callers from New York and Los Angeles differently when {{user_location}} is known before the call:
- {{user_location}} == "New York"- {{user_location}} == "Los Angeles"
The user said something unrelated to every condition — what happens?
In order: if a global node’s condition matches, the agent transitions there. Otherwise, if the node has an else edge, the agent moves through it. If neither, the agent stays in the current node and responds from its instruction.
How do I see the transitions for a past call?
Open the call transcript in the history tab — it shows each transition with the node names it moved from and to. Name your nodes descriptively so this is easy to read.
Is there a limit on the number of transition conditions?
There’s no limit on conditions per node, though each equation condition holds at most 50 equations. Keep the list focused — the more prompt conditions a node has, the harder it is for the LLM to pick the right one.
The agent transitioned to a node whose condition was never met — why?
Check your global prompt and node instructions for numbered labels like “PRIORITY 1”, “Step 2”, or “ATTEMPT 1”. When the agent picks the next node, numbers in these lists can be confused with its transition options, so a transition can fire even though its condition was never met. Rename the items to letters (“PRIORITY A”) or descriptive names (“New service intent”) — the instructions themselves can stay the same.
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