Architecture

Playwright CodeGraph is a deterministic local and CI data plane. It converts repository evidence into a canonical test plan, executes that plan, and produces portable quality artifacts.

Component Flow

Git diff ───────────────┐
Rush workspace graph ──┤
Source code graph ──────┼──> Deterministic planner ──> plan.json
Scenario registry ──────┤              │
Test inventory ─────────┘              ├──> Unit runner
                                       ├──> Playwright runner
                                       └──> HTML quality report

Graph Layers

Layer	Evidence	Purpose
Git graph	merge base, committed, staged, unstaged, and untracked changes	Establish the exact change set
Workspace graph	Rush projects, dependencies, and reverse dependents	Expand package-level impact
Source graph	imports and file reachability from CodeGraph	Find statically affected tests
Scenario graph	journeys, scenario dependencies, code paths, and tests	Express business impact
Runtime graph	optional LCOV or V8 observations	Distinguish declared coverage from observed execution
History graph	shadow and replay records	Measure fallback and missed-failure behavior

Deterministic Boundary

The selector uses only versioned, inspectable inputs:

Git references and working-tree state
Strict configuration
Rush manifests and package manifests
CodeGraph protocol output
Scenario YAML and test annotations
Test file inventory

Identical inputs produce a byte-stable plan. Timestamps and durations belong to execution records, not selection plans.

Fail-Open Safety

The planner expands to a full run when it cannot prove selective execution is safe. Examples include:

Missing, stale, incompatible, or failed graph operations
Incomplete Git history
Unknown repository files
Global configuration triggers
Scenario coverage gaps
Selection or command-length limits
Invalid configuration

AI can explain or recommend work, but it is never the sole reason to skip a test.

Public Contracts

The TypeScript API and CLI share versioned contracts for:

Changed files
Workspace projects
Selection reasons
Full-run reasons
Selection plans
Scenario coverage
Execution, shadow, and replay artifacts

Repository-derived values are escaped before entering the standalone report, and its Content Security Policy blocks external scripts, styles, and resources.

Cross-Platform Execution

The CLI does not use a command shell to run CodeGraph, Vitest, Jest, or Playwright. It resolves local package binaries and launches their JavaScript entry points through Node.js. CI validates Node.js 20 and 22 on Windows and Ubuntu.

Quality Reports Deployment