Detect project stack and generate CI/CD pipeline configuration for GitHub Actions or GitLab CI. TRIGGER when: user asks to set up CI/CD, create a pipeline, add GitHub Actions, configure GitLab CI, or automate testing and deployment. DO NOT TRIGGER when: user is debugging an existing pipeline failure, or asking about deployment infrastructure (servers, containers, cloud).

CI/CD Pipeline Builder

What You Get

GitHub Actions or GitLab CI YAML file ready to commit
Dependency caching, pinned versions, test + lint + build stages

Philosophy

Start with a minimal reliable pipeline that runs tests on every push. Add complexity only when justified. A pipeline that is fast and trustworthy is better than one that is comprehensive and flaky.

Workflow: 5 Phases

Phase 1: Detect Stack

Scan the repository for manifests, lockfiles, and configuration files. See stack-detection.md for the full signal table. Identify:

Primary language(s) and runtime versions
Package manager and lockfile
Test framework and test command
Linter and formatter
Build tool and build command
Monorepo structure (if applicable)

Phase 2: Choose Platform

Default to GitHub Actions unless the project already uses GitLab CI or the user requests otherwise. Check for existing pipeline files:

.github/workflows/*.yml -- GitHub Actions
.gitlab-ci.yml -- GitLab CI

If a pipeline already exists, extend it rather than replacing it.

Phase 3: Generate Pipeline

Start with the minimal reliable baseline from pipeline-templates.md:

Install dependencies (with caching)
Run linter/formatter check
Run tests
Build (if applicable)

Use the detected runtime version. Pin action versions to specific SHAs or major versions. Use lockfile-based caching.

Phase 4: Validate

Before presenting the pipeline to the user:

Verify all referenced tools are in the project's dependencies
Check that test/lint/build commands match the project's configuration
Ensure secrets are referenced by name, not hardcoded
Confirm the runner OS matches the project's requirements

Phase 5: Add Deployment Stages

Only if the user requests deployment. Add stages for:

Staging deployment (on merge to main)
Production deployment (on tag or manual trigger)
Environment-specific secrets and approvals

Keep deployment stages separate from CI stages. CI should pass before deployment is attempted.

WRONG: floating versions

# WRONG: unpinned action version, no caching, floating runtime
- uses: actions/setup-node@latest
- run: npm ci && npm test

CORRECT: pinned and cached

# CORRECT: pinned action, lockfile cache, explicit runtime
- uses: actions/setup-node@v4
  with:
    node-version-file: '.nvmrc'
    cache: 'npm'
- run: npm ci
- run: npm test

Rules

Always cache dependencies. Uncached CI is a waste of compute.
Pin versions: actions, runtimes, dependencies. Floating versions cause flaky builds.
Keep pipelines under 10 minutes. If slower, parallelize or split.
Never store secrets in pipeline files. Use the platform's secrets manager.
Run the full test suite, not a subset. Partial CI is worse than no CI.

Sub-files

File	Topic
stack-detection.md	File signals per ecosystem
pipeline-templates.md	GitHub Actions and GitLab CI scaffolds

ci-cd-pipeline-builder