Snyk Code "SNYK_TOKEN" missing / authentication error in CI

Snyk CLI commands authenticate with an API token. When SNYK_TOKEN is absent from the environment, snyk code test cannot authenticate and fails before analyzing anything.

What this error means

The Snyk step fails with "Authentication error", "Missing SNYK_TOKEN", or a prompt to run snyk auth, typically in a non-interactive CI job.

Snyk

Authentication error (SNYK-0005)
Please run `snyk auth` or set the SNYK_TOKEN environment variable to authenticate.

Common causes

The token secret is not exposed to the step

The workflow never sets SNYK_TOKEN from a secret, so the CLI has no credentials in CI.

Relying on interactive snyk auth

snyk auth opens a browser flow that cannot complete in CI; only the token env var works headlessly.

How to fix it

Set SNYK_TOKEN from a secret

Add the Snyk API token as a repository or org secret.
Expose it as SNYK_TOKEN in the step env.
Re-run so snyk code test authenticates.

.github/workflows/snyk.yml

- run: snyk code test
  env:
    SNYK_TOKEN: ${{ secrets.SNYK_TOKEN }}

Do not use interactive auth in CI

Remove any snyk auth step and rely solely on the SNYK_TOKEN environment variable for headless runs.

How to prevent it

Store the Snyk token as a secret and inject it as SNYK_TOKEN.
Avoid interactive snyk auth in CI.
Fail fast if the token env var is empty.