The Condition block branches a workflow on boolean expressions. It checks each branch in order and runs the path of the first one that is true, with no model call. When you want a model to decide the route, use a Router instead.
Configuration
Conditions
A list of branches: an if, any number of else if rows, and a final else. Each branch holds a JavaScript expression that evaluates to true or false, and connects to its own path. Sim checks them top to bottom and takes the first branch that is true; the else branch runs when none match.
Reference an earlier output inside an expression with a connection tag:
<agent.score> > 75
<ticket.subject>.toLowerCase().includes('urgent')
<user.email>.endsWith('@company.com') && <user.plan> === 'pro'Read an environment variable with {{KEY}}:
{{MAX_RETRIES}} === 3
{{FEATURE_ON}} === true
{{TIER}} === 'pro'Numbers, booleans, and null compare as literals. Every other value is bound as a string, so an apostrophe, quote, or newline inside a secret cannot change what the expression means.
If an expression throws, for example because it reads a field that is not there, the block errors and the run follows the error path if one is connected. Guard missing values with optional chaining (?.) or a null check.
Outputs
| Output | What it is |
|---|---|
<condition.conditionResult> | The boolean result of the branch that matched |
<condition.selectedOption> | The id of the matched branch |
<condition.selectedPath> | The destination block the workflow routed to |
Examples
Route a support ticket by priority
The Condition checks <start.priority> and runs one downstream path. The other does not run, so a reference to a block on the path that did not run comes back empty.
Moderate content by score
An Agent scores the content, and the Condition publishes it or blocks it on <moderate.toxicity>.
Branch onboarding by account tier
A Function reads the account, and the Condition sends enterprise accounts through guided setup and everyone else through the quick start.
Best Practices
- Order branches from specific to general. The first true branch wins, so put narrow checks before catch-alls.
- Always give unmatched runs a path. Connect the else branch, or make the last condition
true, so nothing dead-ends silently. - Keep expressions simple. Short boolean checks are easy to read and debug. Do heavy logic in a Function block first and branch on its result.
- Guard missing values. Use optional chaining (
?.) or a null check so an absent field does not throw.