GitHub Actions "Unable to interpret value as a boolean"

By Daniel Zoghalchali·Latchkey

A key expecting a boolean got a value that is not true or false, often a quoted string or an empty expression result.

What this error means

The workflow fails with "Unable to interpret value as a 'boolean'" at a key such as continue-on-error or an input typed boolean.

The workflow is not valid. .github/workflows/ci.yml (Line: 14): Unable to interpret value as a 'boolean': 'yes'

Common causes

A non-boolean literal

Values like yes, no, or 1 are not booleans here; only true and false are accepted.

An expression returning a string

An expression that yields a quoted string instead of an actual boolean fails the type check.

How to fix it

Provide a real boolean

1. Use unquoted true or false.
2. For expressions, compare to produce a boolean, not a string.

continue-on-error: ${{ github.ref != 'refs/heads/main' }}

How to prevent it

• Avoid quoting boolean values in YAML.
• Run actionlint to catch boolean type mismatches.

Frequently asked questions

Related guides

References

• GitHub Actions documentation
• Workflow syntax for GitHub Actions