Genie: typed TS steps for CI workflows to replace bash string concatenation

Problem

CI workflow genie files (ci.yml.genie.ts) currently construct bash scripts via TS string arrays/template literals. This is error-prone and hard to maintain:

• ${} clashes between TS template literals and bash variable expansion
• Quote escaping (e.g. '"'"' inside grep patterns)
• Fragile text extraction (grep-based URL parsing, PIPESTATUS handling)
• No IDE support inside bash strings
• None of the CI step logic is testable

Example — runVercelDeploy in schickling.dev builds a 12-line bash script via [].join('\n') to run a devenv task, capture output, extract a URL via grep, and write to $GITHUB_ENV.

Proposed approach

Two complementary pieces:

1. @overeng/ci-helpers runtime library

Typed primitives for common CI operations that step scripts import:

• GitHubActions.fromEnv() — read event JSON, setEnv(), setOutput(), addPath(), annotations
• exec() — subprocess with stdout capture, tee, exit code
• Domain helpers (e.g. Vercel URL extraction)

2. tsStep helper in genie's github-workflow generator

Thin helper that codifies the convention of referencing a TS module from a workflow step:

tsStep({
  name: 'Deploy',
  module: '.github/ci/deploy.ts',
  env: { DEPLOY_TASK: '...', VERCEL_TOKEN: '${{ secrets.VERCEL_TOKEN }}' },
})
// → generates: { name: 'Deploy', shell: 'bash', env: {...}, run: 'bun .github/ci/deploy.ts' }

Optional: genie's validate() hook checks that the referenced module exists.

Result

Step logic lives in real .ts files with full IDE support and testability. The genie file stays focused on workflow structure (jobs, triggers, permissions, step ordering). The boundary is explicit — genie owns the shape, TS modules own the runtime logic.

This issue was created on behalf of @schickling by Claude Code.

Start by reading the ci.yml.genie.ts workflow generators and the runVercelDeploy example in schickling.dev, then review the proposed @overeng/ci-helpers and tsStep boundaries. Done means common CI operations have typed TypeScript primitives, workflow steps can reference TS modules with their environment, and step logic is testable outside bash strings.