Environment variables
gluon uses a small set of environment variables for configuration and runtime context.
Variables that affect CLI behavior
| Variable | Meaning |
|---|---|
GLUON_CONFIG_DIR | Default value for the global --config-dir legacy fallback |
GLUON_RUNNER | Default runner for gluon run |
GITHUB_ACTIONS | Causes run to auto-select the GitHub Actions backend when set to true |
GITHUB_WORKSPACE | Used as the default workdir for the GitHub Actions backend when --workdir is not set |
Variables injected during execution
| Variable | Meaning |
|---|---|
GLUON_CONTEXT | Runtime environment label such as local, container, or ci |
GLUON_RUNNER | Resolved runner name for the current step |
GitHub Actions compatibility mode
When the GitHub Actions backend is active, gluon also supports standard GitHub Actions workflow command behavior such as GITHUB_ENV, GITHUB_OUTPUT, and GITHUB_PATH handling inside the compatibility engine.
Prefer CLI flags when you need per-command overrides, and reserve environment variables for CI defaults or workspace-wide configuration.
Most new workflows should declare composition sources in intent.yaml instead of relying on GLUON_CONFIG_DIR.