Prevent Vercel preview fan-out for documentation-only changes

[atomicdjt]

Objective

Prevent one documentation or governance commit in the monorepo from automatically attempting preview builds across every connected Vercel project.

Context

The repository already contains an affected-project selector and guarded deployment workflow. Vercel’s native Git integrations still fan out independently, which caused a burst of preview deployments and exhausted the account build-rate allowance during a documentation-only remediation branch.

Safety principle

Do not disable or reconfigure all projects simultaneously. Prove the cutover on one low-risk project, preserve rollback, and change the remaining projects only after successful verification.

Acceptance criteria

• Inventory each connected Vercel project, root directory, production branch, build settings, domains, aliases, environment-variable names/scopes, and Git integration.
• Confirm the affected-project selector correctly returns no deployable applications for docs-only changes.
• Select one low-risk project for a controlled preview cutover.
• Configure an ignored-build command or disable native Git previews only for that test project.
• Push one test branch changing unrelated documentation and verify no native preview starts for the test project.
• Push one test branch changing the project’s source and verify exactly one intended preview can be launched through the approved controller.
• Confirm production deployment behavior remains unchanged.
• Document rollback steps and restore the original setting if any check fails.
• Roll out one project at a time only after the test succeeds.
• Record final evidence showing docs-only changes no longer create multi-project build fan-out.

Required verification

• GitHub workflow plan output
• Vercel deployment history before and after
• Source commit and branch traceability
• Canonical production routes returning the intended application
• No lost domains, aliases, secrets, or production triggers

Non-goals

• Upgrading Vercel solely to mask inefficient deployment behavior
• Disabling production deployments without a replacement path
• Bulk project-setting changes without rollback evidence
• Treating a build-rate-limit error as an application-code failure