fix: Fix holon linking in decide phase (DRR)

Author: m0n0x41d

CHANGELOG.md

@@ -9,6 +9,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **DRR Linking (FPF E.9)**: Decision records now create graph relations to hypotheses.
+  - `quint_decide` accepts new `rejected_ids` parameter for rejected alternatives.
+  - Creates `selects` relation: DRR → winner hypothesis.
+  - Creates `rejects` relations: DRR → each rejected alternative.
+  - Enables queries: "What alternatives were considered for this DRR?"
+
 - **sqlc Integration**: Type-safe database queries generated from SQL.
   - All database operations now use sqlc-generated code with proper type safety.
   - New `db/store.go` wrapper provides clean API while preserving schema bootstrap.

src/mcp/cmd/commands/q5-decide.md

@@ -72,6 +72,7 @@ Computes R_eff for comparison.
 Finalizes the decision and creates the DRR.
 -   **title**: Title of the decision (e.g., "Use Redis for Caching").
 -   **winner_id**: The ID of the chosen hypothesis.
+-   **rejected_ids**: Array of IDs of rejected L2 alternatives (creates `rejects` relations).
 -   **context**: The problem statement.
 -   **decision**: "We decided to use [Winner] because..."
 -   **rationale**: "It had the highest R_eff and best fit for constraints..."
@@ -95,10 +96,21 @@ Presenting comparison:
 
 [User responds: "redis-caching"]
 
-[Call quint_decide(winner_id="redis-caching", title="Use Redis for Caching", ...)]
+[Call quint_decide(
+    title="Use Redis for Caching",
+    winner_id="redis-caching",
+    rejected_ids=["cdn-edge"],
+    context="...",
+    decision="...",
+    rationale="...",
+    consequences="..."
+)]
 → DRR created at .quint/decisions/DRR-XXXX-use-redis-for-caching.md
+→ Relations created:
+  - DRR --selects--> redis-caching
+  - DRR --rejects--> cdn-edge
 
-Result: Decision recorded. Ready for implementation.
+Result: Decision recorded with full audit trail. Ready for implementation.
 ```
 
 ## Example: Failure Path (Transformer Mandate Violation)

src/mcp/internal/fpf/integration_test.go

@@ -321,7 +321,7 @@ func TestFullFPFWorkflowIntegration(t *testing.T) {
 			t.Fatalf("SaveState failed: %v", err)
 		}
 
-		path, err := tools.FinalizeDecision("Final Decision", finalWinnerID, "Context", "Decision", drrContent, "Consequences", "Characteristics")
+		path, err := tools.FinalizeDecision("Final Decision", finalWinnerID, nil, "Context", "Decision", drrContent, "Consequences", "Characteristics")
 		if err != nil {
 			t.Fatalf("FinalizeDecision failed: %v", err)
 		}

src/mcp/internal/fpf/server.go

@@ -225,8 +225,13 @@ func (s *Server) handleToolsList(req JSONRPCRequest) {
 			InputSchema: map[string]interface{}{
 				"type": "object",
 				"properties": map[string]interface{}{
-					"title":           map[string]string{"type": "string"},
-					"winner_id":       map[string]string{"type": "string"},
+					"title":     map[string]string{"type": "string"},
+					"winner_id": map[string]string{"type": "string"},
+					"rejected_ids": map[string]interface{}{
+						"type":        "array",
+						"items":       map[string]string{"type": "string"},
+						"description": "IDs of rejected L2 alternatives",
+					},
 					"context":         map[string]string{"type": "string"},
 					"decision":        map[string]string{"type": "string"},
 					"rationale":       map[string]string{"type": "string"},
@@ -402,7 +407,15 @@ func (s *Server) handleToolsCall(req JSONRPCRequest) {
 
 	case "quint_decide":
 		s.tools.FSM.State.Phase = PhaseDecision
-		output, err = s.tools.FinalizeDecision(arg("title"), arg("winner_id"), arg("context"), arg("decision"), arg("rationale"), arg("consequences"), arg("characteristics"))
+		var rejectedIDs []string
+		if rids, ok := params.Arguments["rejected_ids"].([]interface{}); ok {
+			for _, r := range rids {
+				if s, ok := r.(string); ok {
+					rejectedIDs = append(rejectedIDs, s)
+				}
+			}
+		}
+		output, err = s.tools.FinalizeDecision(arg("title"), arg("winner_id"), rejectedIDs, arg("context"), arg("decision"), arg("rationale"), arg("consequences"), arg("characteristics"))
 		if err == nil {
 			s.tools.FSM.State.Phase = PhaseIdle
 			if saveErr := s.tools.FSM.SaveState(s.tools.GetFPFDir() + "/state.json"); saveErr != nil {

src/mcp/internal/fpf/tools.go

@@ -481,7 +481,7 @@ func (t *Tools) RefineLoopback(currentPhase Phase, parentID, insight, newTitle,
 	return childPath, nil
 }
 
-func (t *Tools) FinalizeDecision(title, winnerID, decisionContext, decision, rationale, consequences, characteristics string) (string, error) {
+func (t *Tools) FinalizeDecision(title, winnerID string, rejectedIDs []string, decisionContext, decision, rationale, consequences, characteristics string) (string, error) {
 	defer t.RecordWork("FinalizeDecision", time.Now())
 
 	body := fmt.Sprintf("\n# %s\n\n", title)
@@ -510,10 +510,27 @@ func (t *Tools) FinalizeDecision(title, winnerID, decisionContext, decision, rat
 	}
 
 	if t.DB != nil {
+		ctx := context.Background()
 		drrID := t.Slugify(title)
-		if err := t.DB.CreateHolon(context.Background(), drrID, "DRR", "", "DRR", title, body, "default", "", winnerID); err != nil {
+		if err := t.DB.CreateHolon(ctx, drrID, "DRR", "", "DRR", title, body, "default", "", winnerID); err != nil {
 			fmt.Fprintf(os.Stderr, "Warning: failed to create DRR holon in DB: %v\n", err)
 		}
+
+		// Create selects relation: DRR → winner
+		if winnerID != "" {
+			if err := t.createRelation(ctx, drrID, "selects", winnerID, 3); err != nil {
+				fmt.Fprintf(os.Stderr, "Warning: failed to create selects relation: %v\n", err)
+			}
+		}
+
+		// Create rejects relations: DRR → each rejected alternative
+		for _, rejID := range rejectedIDs {
+			if rejID != "" && rejID != winnerID {
+				if err := t.createRelation(ctx, drrID, "rejects", rejID, 3); err != nil {
+					fmt.Fprintf(os.Stderr, "Warning: failed to create rejects relation to %s: %v\n", rejID, err)
+				}
+			}
+		}
 	}
 
 	if winnerID != "" {

src/mcp/internal/fpf/tools_test.go

@@ -283,7 +283,7 @@ func TestFinalizeDecision(t *testing.T) {
 	title := "Final Project Decision"
 	content := "This is the DRR content for the decision."
 
-	drrPath, err := tools.FinalizeDecision(title, winnerID, "Context", content, "Rationale", "Consequences", "Characteristics")
+	drrPath, err := tools.FinalizeDecision(title, winnerID, nil, "Context", content, "Rationale", "Consequences", "Characteristics")
 	if err != nil {
 		t.Fatalf("FinalizeDecision failed: %v", err)
 	}