8398a7/action-slack "Error: Specify secrets.SLACK_WEBHOOK_URL" (missing webhook)

action-slack reads the webhook URL from the SLACK_WEBHOOK_URL env var. Without it the action cannot post and errors immediately.

What this error means

The Slack notify step fails with "missing webhook" or "Specify secrets.SLACK_WEBHOOK_URL".

Error: Specify secrets.SLACK_WEBHOOK_URL
##[error]Error: missing webhook

Common causes

Webhook env not set

SLACK_WEBHOOK_URL was not exported on the step env.

Secret unavailable on fork PRs

On fork-originated PRs the secret is not exposed, so the env is empty.

How to fix it

Provide the webhook via env

1. Set SLACK_WEBHOOK_URL under env on the action-slack step.
2. Gate the notify on non-fork runs if the secret is unavailable for forks.
3. Re-run the workflow.

- uses: 8398a7/action-slack@v3
  if: ${{ always() }}
  with:
    status: ${{ job.status }}
  env:
    SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}

How to prevent it

• Pass webhook URLs via env to the notify step.
• Skip notifications on fork PRs where secrets are not available.

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