arch-drift

name	arch-drift
description	Detect violations of architectural decisions in the codebase. Checks module dependency direction rules, identifies boundary violations, and reports drift between documented decisions and actual code.
allowed-tools	Read, Bash(git *), Bash(ls *), Bash(bash plugins/*)
user-invocable	true

Architecture Drift --- Decision Conformance Checking

Detect whether the codebase conforms to documented architectural decisions. Checks dependency direction rules, identifies module boundary violations, and reports drift with references to governing ADRs.

Command

/arch-drift [--module <path>] [--strict]

Arguments

Argument	Required	Description
--module <path>	No	Scope analysis to a single module. Checks all modules if omitted.
--strict	No	Exit non-zero on any error-severity violation. For CI use.

Workflow

1. Scan modules. Discover all modules:

   bash ../arch-map/scripts/scan-modules.sh [--module <path>]
   

2. Read accepted ADRs. For each ADR in docs/decisions/ with status accepted:

   • Extract the architectural constraints it declares
   • Note which modules it governs (by path references in the body)
   • Focus on the "Decision" section for specific rules or patterns

3. Check dependency direction. For each module, run the boundary checker:

   bash scripts/check-boundaries.sh --module <path> --type <type>
   

   This scans source files for import statements and checks them against the dependency direction rules:

   Module Type	Can Depend On	Cannot Depend On
   app	lib, core	other app
   lib	core	app, lib*
   core	(none internal)	app, lib

   *Cross-lib dependencies are allowed if explicitly declared in the module's CLAUDE.md ## Dependencies section.

4. Classify findings. Each violation is classified by severity:

   • Error: Clear dependency direction violation (e.g., core importing from app)
   • Warning: Probable violation with heuristic uncertainty
   • Info: Governance observations (e.g., no ADR covers this module)

5. Reference governing ADRs. For each violation, identify which ADR established the rule being violated and include the reference in the report.

6. Report results. Output a structured report:

   Architecture drift analysis:
     Modules checked: 8
     Violations found: 3
       Errors: 1
       Warnings: 2
   
     ERROR: packages/core/src/utils.ts:15
       Imports from packages/api (app) — core cannot depend on app
       Governing ADR: ADR-014 (Heuristic Architecture Governance)
   
     WARNING: packages/auth-lib/src/client.ts:42
       Imports from packages/shared-lib (lib) — lib-to-lib not declared
       Declare in CLAUDE.md ## Dependencies to allow
   

7. Strict mode. If --strict is specified and any error-severity violations exist, report failure. This enables CI integration.

Scripts

• scripts/check-boundaries.sh --- Scan source files for import violations against dependency direction rules