> ## Documentation Index
> Fetch the complete documentation index at: https://praison.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Evaluate Condition • AI Agent SDK
> evaluate_condition: Evaluate a condition expression with variable substitution.
# evaluate\_condition
Function
> This function is defined in the [**evaluator**](../modules/evaluator) module.
Evaluate a condition expression with variable substitution.
This is the shared condition evaluation function used by both
AgentFlow and AgentTeam. It supports various condition formats.
Supported formats:
* Numeric comparison: "\{\{var}} > 80", "\{\{var}} >= 50", "\{\{var}} \< 10"
* String equality: "\{\{var}} == approved", "\{\{var}} != rejected"
* Contains check: "error in \{\{message}}", "\{\{status}} contains success"
* Boolean: "\{\{flag}}" (truthy check)
* Nested property: "\{\{item.score}} >= 60"
## Signature
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
def evaluate_condition(condition: str, variables: Dict[str, Any], previous_output: Optional[str]) -> bool
```
## Parameters
Condition expression with \{\{var}} placeholders.
Dictionary containing variables for substitution.
Optional output from previous step (substitutes \{\{previous\_output}}).
### Returns
Boolean result of condition evaluation.
Returns False on evaluation errors (fail-safe).
## Usage
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
result = evaluate_condition("{{score}} > 80", {"score": 90}) # True
result = evaluate_condition("{{status}} == approved", {"status": "approved"}) # True
result = evaluate_condition("error in {{message}}", {"message": "An error occurred"}) # True
```
## Uses
* `re.findall`
* `get_nested_value`
* `re.match`
* `numeric_match.group`
* `string_match.group`
* `logger.warning`
## Used By
* [`ExpressionCondition.evaluate`](../functions/ExpressionCondition-evaluate)
* [`Task.evaluate_when`](../functions/Task-evaluate_when)
## Source
`praisonaiagents/conditions/evaluator.py` at line 131
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