Terraform CLI
Terraform could not convert the value to bool
Error: Invalid function argument
Terraform could not convert the supplied value to a boolean because tobool only accepts booleans, null, or the exact strings true and false.
Error AtlasError Documentation and ResolutionObserved message
Error: Invalid function argument
Why it happens
- The expression passes a string like no, yes, or another unsupported value to tobool.
- The function receives a number, collection, or other non-boolean-compatible type.
- Input normalization assumes Terraform can coerce values that tobool rejects.
How to fix it
- Validate the input before calling tobool and pass only supported boolean-like values.
- Normalize upstream variables so they are already bool values when possible.
- Use explicit branching logic if the input space includes values beyond true, false, or null.
Official reference
tobool functionRelated errors
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