diff --git a/CLAUDE.md b/CLAUDE.md
index dbb119a..0780dc1 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -23,10 +23,14 @@ Usage example in a workflow:
 
 ### Core Classes (src/)
 
-- **`Jira`** - Wrapper around `jira.js` Version2Client. Handles all Jira API calls including fetching/creating versions and updating issue fixVersions.
-- **`Issue`** - Represents a single Jira issue. Fetches current fixVersions, applies new versions, and tracks before/after state for reporting.
-- **`EventManager`** - Parses issue keys from input, applies project filters (include/exclude), and orchestrates the fixVersion update process.
-- **`Action`** - Entry point. Creates Jira client and EventManager, executes the update workflow.
+- **`index.ts`** - Entry point that imports Action and input-helper, executes the action workflow, and handles top-level error reporting via `core.setFailed()`.
+- **`action.ts`** - Main action orchestrator. Creates Jira client and EventManager, executes the fixVersion update workflow.
+- **`Jira.ts`** - Wrapper around `jira.js` Version2Client. Handles all Jira API calls including fetching/creating versions and updating issue fixVersions.
+- **`Issue.ts`** - Represents a single Jira issue. Fetches current fixVersions, applies new versions, and tracks before/after state for reporting.
+- **`EventManager.ts`** - Parses issue keys from input, applies project filters (include/exclude), and orchestrates the fixVersion update process.
+- **`input-helper.ts`** - Parses and validates GitHub Action inputs from environment variables (`JIRA_BASE_URL`, `JIRA_API_TOKEN`, `JIRA_USER_EMAIL`, `GITHUB_TOKEN`, `GITHUB_WORKSPACE`) and action inputs (`jira_base_url`, `jira_api_token`, `jira_user_email`, `token`, `projects`, `projects_ignore`, `fix_versions`, `issues`, `fail_on_error`).
+- **`fs-helper.ts`** - File system utilities providing `existsSync()`, `directoryExistsSync()`, `fileExistsSync()`, and `loadFileSync()` with input validation and error handling.
+- **`utils.ts`** - General utility functions including `issueIdRegEx` (Jira issue key regex pattern), `isError()` (type guard for Node.js errors), `toCommaDelimitedString()`, `nullIfEmpty()`, and `formatDate()` (ISO 8601 date formatting).
 
 ### Key Dependency: jira.js
 
@@ -61,18 +65,28 @@ yarn lint:markdown      # Check markdown syntax
 yarn lint:markdown:fix  # Auto-fix markdown issues
 
 # Unit tests (Vitest, mocked Jira)
-yarn test
-yarn test:watch
-yarn test -- --testNamePattern="pattern" # Run specific test
+yarn test                                     # Run all tests
+yarn test:watch                               # Run tests in watch mode
+yarn test -- --testNamePattern="pattern"      # Run specific test by name
+yarn test:unit                                # Run unit tests only (sets defaults, handles missing)
+yarn test:integration                         # Run integration tests only (GitHub Event)
+yarn test-ci                                  # Run tests with JUnit reporter for CI (outputs junit.xml)
+
+# Full build + validation pipeline
+yarn all        # Build, format, lint, package, and test in sequence
+
+# Commit helper
+yarn commit     # Interactive conventional commit helper (git-cz)
 
 # E2E tests (requires Docker and Playwright)
 yarn e2e:up           # Start Jira + MySQL containers
-yarn e2e:setup        # Run Playwright setup wizard automation
+yarn e2e:setup        # Run Playwright setup wizard automation (headless Chromium)
+yarn e2e:setup:http   # Alternative HTTP-based Jira setup (non-Playwright, uses direct HTTP/database)
 yarn e2e:wait         # Wait for Jira API ready
 yarn e2e:seed         # Create test project/issues
 yarn e2e:test         # Run E2E test suite
 yarn e2e:logs         # Show Docker container logs
-yarn e2e:down         # Stop containers
+yarn e2e:down         # Stop containers and remove volumes
 yarn e2e:all          # Full E2E sequence (up -> setup -> wait -> seed -> test)
 yarn e2e:fast         # Fast E2E (restore from snapshots if valid, else full setup)
 
@@ -86,7 +100,11 @@ yarn e2e:snapshot:save    # Save current Docker volumes as snapshots
 
 ### Unit Tests
 
-Located in `__tests__/`. Uses Vitest with mocked Jira client via `vi.mock('../src/Jira')`. Mock data is inline in test files due to Vitest hoisting. Test fixtures are in `__tests__/fixtures/`.
+Located in `__tests__/`. Uses Vitest with mocked Jira client via `vi.mock('../src/Jira')`. Test fixtures are in `__tests__/fixtures/`.
+
+**Mock Infrastructure** (`__tests__/mocks/`):
+
+- `jira-api.ts` - Provides mock implementations for Jira class methods, including `mockJiraData` (in-memory storage for issues, projects, versions), `resetMockData()`, `setupDefaultMockData()`, and `createMockJiraInstance()` factory function for creating fully-mocked Jira clients.
 
 ### E2E Tests
 
@@ -94,16 +112,30 @@ Located in `e2e/`. Uses a Dockerized Jira Data Center instance (`haxqer/jira:9.1
 
 **E2E Scripts** (`e2e/scripts/`):
 
+- `e2e-config.ts` - Central E2E configuration interface. Defines `E2EConfig` type and `getE2EConfig()` function that returns Data Center config (basic auth) by default, or Jira Cloud config when `E2E_JIRA_EMAIL` and `E2E_JIRA_API_TOKEN` environment variables are set.
 - `setup-jira-playwright.ts` - Automates Jira setup wizard via headless Chromium (handles XSRF)
+- `setup-jira.ts` - Alternative HTTP-based Jira setup. Uses direct HTTP requests and database insertion to configure Jira without Playwright. Handles license generation via atlassian-agent, database license insertion, container restart, and admin account setup.
 - `jira-client.ts` - E2E test client using jira.js (same library as main action)
 - `seed-jira.ts` - Creates test project, versions, and issues
 - `wait-for-jira.ts` - Polls until Jira API is ready
-- `snapshot-*.ts` - Docker volume snapshot management for CI caching
+- `snapshot-check.ts` - Validates Docker volume snapshots
+- `snapshot-save.ts` - Saves Docker volumes as snapshots
+- `snapshot-restore.ts` - Restores Docker volumes from snapshots
 
 **E2E Test Files** (`e2e/tests/`):
 
 - `fixversion.e2e.test.ts` - Tests fixVersion creation and assignment via the Jira API
 
+## CI Workflows
+
+Located in `.github/workflows/`:
+
+- **`ci.yml`** - Main CI pipeline. Runs on PRs to main/develop and pushes to main. Includes validate job (type check, lint, build, verify dist up-to-date) and unit tests.
+- **`unit-tests.yml`** - Standalone unit test runner. Runs on PRs to main/develop and pushes to main. Executes `yarn test` and builds.
+- **`e2e-jira.yml`** - E2E tests with Dockerized Jira Data Center. Supports snapshot restore for faster runs. Has `skip_snapshots` workflow_dispatch input to force full setup.
+- **`build-e2e-snapshots.yml`** - Scheduled workflow (every 5 days at 3am UTC) to build and upload E2E Docker volume snapshots. Supports `force_rebuild` workflow_dispatch input.
+- **`push_code_linting.yml`** - Biome linting on pull requests with reviewdog integration for PR review comments.
+
 ## Build and TypeScript Configuration
 
 - **Build System**: Rollup with TypeScript plugin (see `rollup.config.ts`)
diff --git a/README.md b/README.md
index f943666..087313c 100644
--- a/README.md
+++ b/README.md
@@ -79,3 +79,33 @@ This action will add the supplied list of FixVersions to the list of Jira Issue
 TODO:
 
 - [ ] Add a `operation` input that can take an `add`, `set`, or `remove` modifier for the list of fixversions, for how to treat the list of FixVersions supplied. Append would add any new fixversions to the issues fixversions list, replace removes existing fix versions first, and remove would remove any fix versions from the issue that are supplied from the input list of fix_versions
+
+## Development
+
+### Prerequisites
+
+- Node.js >= 22.0.0
+- Yarn package manager
+- Docker (for E2E tests)
+
+### Available Scripts
+
+```bash
+yarn build        # Build the action (Rollup ESM bundle)
+yarn test         # Run unit tests (Vitest)
+yarn lint         # Check linting (Biome)
+yarn lint:fix     # Auto-fix linting issues
+yarn format       # Format code (Biome)
+yarn e2e:all      # Run full E2E test suite
+```
+
+### Tooling
+
+- **Biome** for linting and formatting (replaces ESLint + Prettier)
+- **Vitest** for unit testing (replaces Jest)
+- **Rollup** for bundling (ESM output)
+
+### Node Version Note
+
+- Development requires **Node 22+**
+- GitHub Actions runtime uses **Node 20** (GitHub doesn't support node22 yet)
diff --git a/e2e/README.md b/e2e/README.md
index c6b9054..9cbfbe8 100644
--- a/e2e/README.md
+++ b/e2e/README.md
@@ -365,4 +365,5 @@ UI testing is brittle and slow. REST API testing is:
 
 - [Jira REST API Documentation](https://developer.atlassian.com/cloud/jira/platform/rest/v2/)
 - [Docker Compose Documentation](https://docs.docker.com/compose/)
-- [Atlassian Docker Images](https://hub.docker.com/r/atlassian/jira-software)
+- [haxqer/jira Docker Image](https://hub.docker.com/r/haxqer/jira) - Third-party Jira Data Center image used by this project (`haxqer/jira:9.17.5`)
+- [Atlassian Docker Images](https://hub.docker.com/r/atlassian/jira-software) - Official images (for reference; not used in this project)