Generate and Optimize CircleCI Configurations

This skill covers creating, optimizing, and troubleshooting CircleCI configuration files, with deep knowledge of CircleCI capabilities, best practices, workflows, orbs, and deployment strategies across tech stacks. Its core principles are always using CircleCI version 2.1 for maximum flexibility, structuring configs with clear version/orbs/jobs/workflows separation, using meaningful job and workflow names, and using parameters and executors for reuse - plus resource optimization through appropriate resource classes, Docker layer caching, parallelism for test suites, and strategic dependency/artifact caching. It provides core templates for a basic Node.js project using the circleci/node orb, Docker build-and-push using the circleci/docker orb with remote Docker layer caching, multi-environment deployment workflows with branch filters and manual approval holds before production, matrix builds testing multiple Node versions via pipeline parameters, dependency caching with checksum-based cache keys, workspace persistence between build and deploy jobs, context-based secret sharing across projects, a comprehensive test pipeline with parallelism and circleci tests split for timing-based test splitting, and Slack notification integration on pass/fail events.

Use this skill when writing or optimizing CircleCI 2.1 pipelines that need orb-based reuse, multi-environment deployment with approval gates, or matrix testing across versions. It names concrete debugging practices - validate configs locally with circleci config validate before pushing, use SSH debugging for build issues, and implement proper timeout settings to prevent hung jobs - and cost-management guidance like using resource_class: small for lightweight jobs and monitoring credit usage against resource classes. It is not a general CI/CD theory guide - it's scoped to CircleCI's specific YAML schema, orb ecosystem, and pipeline features, and its security guidance is specific to CircleCI contexts and environment variables rather than broader secrets-management architecture.

version: 2.1

orbs:
  node: circleci/node@5.0.2

executors:
  node-executor:
    docker:
      - image: cimg/node:18.17
    resource_class: medium

jobs:
  install-and-test:
    executor: node-executor
    steps:
      - checkout
      - node/install-packages:
          cache-path: ~/project/node_modules
          override-ci-command: npm ci
      - run:
          name: Run tests
          command: npm test
      - store_test_results:
          path: ./test-results

workflows:
  test-and-deploy:
    jobs:
      - install-and-test

Given a project's tech stack and deployment needs, the skill produces complete .circleci/config.yml files like the one above: orb-based job definitions, multi-environment workflows with branch filters and approval jobs, matrix-parameterized test jobs, cache restore/save steps keyed on lockfile checksums, workspace persist/attach steps for cross-job artifact sharing, context blocks for shared secrets, parallelized test jobs with circleci tests glob/circleci tests split, and Slack orb notification steps.

Engineering teams setting up or optimizing CircleCI pipelines who want orb-based, reusable configuration rather than hand-rolled steps - covering the full lifecycle from install/test through multi-environment deployment with approval gates and Slack notifications. It suits teams that care about pipeline cost (resource class selection, credit monitoring) and reliability (timeout settings, local config validation, proper error handling) as much as getting the pipeline to pass.