Icpg

┌────────────────────────────────────────────────────────────────┐
│  iCPG = AST + CFG + PDG + RG (Reason Graph)                    │
│  ─────────────────────────────────────────────────────────────│
│  AST  = Abstract Syntax Tree (structure)      ← existing       │
│  CFG  = Control Flow Graph (execution paths)  ← existing       │
│  PDG  = Program Dependency Graph              ← existing       │
│  RG   = Reason Graph (WHY layer)              ← THIS SKILL     │
│                                                                │
│  The RG stores ReasonNodes (goals/tasks), links them to code   │
│  symbols via typed edges, enforces contracts (DbC), and        │
│  detects when code drifts from its original purpose.           │
│                                                                │
│  Storage: .icpg/reason.db (SQLite, per-project, gitignored)   │
│  CLI: icpg init | create | record | query | drift | bootstrap │
└────────────────────────────────────────────────────────────────┘

id              UUID
goal            Natural language: what is this trying to achieve
decision_type   business_goal | arch_decision | task | workaround | constraint | patch
scope           Files/modules expected to be touched
owner           Human or agent accountable
status          proposed | executing | fulfilled | drifted | abandoned
source          manual | commit | inferred | agent-session

FORMAL CONTRACT (Design by Contract):
  preconditions    What must be true before this intent executes
  postconditions   What must be true when fulfilled
  invariants       What must remain true throughout and after

CREATES      Reason  → Symbol   (this intent created this function)
MODIFIES     Reason  → Symbol   (this intent changed this function)
REQUIRES     Reason  → Reason   (B depends on A being done first)
DUPLICATES   Reason  → Reason   (these two goals overlap)
VALIDATED_BY Reason  → Test     (this test proves the intent was satisfied)
DRIFTS_FROM  Symbol  → Reason   (this symbol no longer does what it was made for)

icpg init                          # Create .icpg/ and database
icpg bootstrap --days 90           # Infer ReasonNodes from git history
icpg bootstrap --days 90 --no-llm  # Without LLM (commit-message only)

icpg create "Add JWT auth" --scope src/auth/ --owner feature-auth --type task
icpg record --reason <id> --base main         # Record symbols from git diff
icpg record --reason <id> --edge-type MODIFIES # Record as modifications

icpg query prior "user authentication"     # 1. Duplicate detection
icpg query constraints src/auth/service.ts  # 2. Invariants for file
icpg query risk validateToken              # 3. Symbol risk profile
icpg query context src/auth/service.ts     # All intents for a file
icpg query blast <reason-id>               # Full blast radius

icpg drift check          # Full scan across all dimensions
icpg drift resolve <id>   # Mark drift event resolved

icpg status               # Stats: reasons, symbols, edges, drift

.icpg/
  reason.db       SQLite database (4 tables: reasons, symbols, edges, drift_events)
  .gitignore      Contains: *
  chroma/         ChromaDB vectors (if chromadb installed)
  tfidf_cache.json  TF-IDF fallback cache
  .current-intent   Marker file for active intent (used by Stop hook)

pip install ./scripts/icpg            # Core (zero deps)
pip install "./scripts/icpg[vectors]"  # + ChromaDB for duplicate detection
pip install "./scripts/icpg[all]"      # + ChromaDB + scikit-learn + openai

0. INTENT       → icpg create (or identify existing intent)
1. DEDUP        → icpg query prior (check for duplicate work)
2. CONSTRAINTS  → icpg query constraints (understand invariants)
3. RISK         → icpg query risk (check fragile symbols)
4. LOCATE       → search_graph to find symbols (code-graph skill)
5. CHANGE       → Make the edit (PreToolUse hook shows context)
6. RECORD       → icpg record (link symbols to intent)
7. DRIFT CHECK  → icpg drift check (verify no unintended drift)
8. VERIFY       → Run tests, lint, typecheck

{
  "hooks": {
    "PreToolUse": [{
      "matcher": "Edit|Write",
      "hooks": [{
        "type": "command",
        "command": "scripts/icpg-pre-edit.sh",
        "timeout": 3,
        "statusMessage": "Checking intent context..."
      }]
    }]
  }
}

═══ iCPG CONTEXT ═══
INTENTS for src/auth/service.ts:
  [>] a1b2c3d4 — User authentication with JWT tokens
      Owner: feature-auth | Status: executing
      Invariants: 2
CONSTRAINTS for src/auth/service.ts:
  From intent: User authentication with JWT tokens
    INV: file_exists("src/auth/middleware.ts")
    POST: test_exists("src/auth/__tests__/service.test.ts")
PRESERVE function signatures unless your task requires changing them.
═══════════════════

{
  "hooks": {
    "Stop": [{
      "hooks": [
        {"type": "command", "command": "scripts/tdd-loop-check.sh", "timeout": 60},
        {"type": "command", "command": "scripts/icpg-stop-record.sh", "timeout": 5}
      ]
    }]
  }
}

 0. INTENT       Team lead creates ReasonNode from feature spec
 0b. DEDUP       icpg query prior — check for duplicate intents
 1. SPEC         Feature agent writes spec
 2. SPEC-REVIEW  Quality agent reviews spec + intent alignment
 3. TESTS (RED)  Feature agent writes tests
 4. RED-VERIFY   Quality agent verifies tests fail
 5. IMPLEMENT    Feature agent codes (PreEdit hook shows context)
 5b. RECORD      Auto-record symbols → intent (Stop hook)
 5c. DRIFT-CHECK Quality agent verifies no scope drift
 6. GREEN-VERIFY Quality agent verifies tests pass + coverage
 7. VALIDATE     Lint + typecheck + full suite
 8. CODE-REVIEW  Review agent (sees intent context per file)
 9. SECURITY     Security agent
10. BRANCH-PR    Merger agent (PR includes intent traceability)