diff --git a/src/mir/builder/control_flow/joinir/merge/instruction_rewriter.rs b/src/mir/builder/control_flow/joinir/merge/instruction_rewriter.rs
index 759f8f6f..28761c27 100644
--- a/src/mir/builder/control_flow/joinir/merge/instruction_rewriter.rs
+++ b/src/mir/builder/control_flow/joinir/merge/instruction_rewriter.rs
@@ -365,9 +365,17 @@ pub(super) fn merge_and_rewrite(
     // The issue was that pre-pass used stale remapper values before Phase 33-21 updates.
     // Instead, we now generate Copies for non-carrier params in the main block processing loop.
 
-    // Phase 286C-2.1 Step 2: Call scan_blocks() to establish 3-stage pipeline
-    // Currently returns empty plan - future steps will extract instruction scanning logic
-    let _scan_plan = scan_blocks(mir_module, remapper, value_to_func_name, &ctx, debug)?;
+    // Phase 286C-2.1 Step 3: Call scan_blocks() to identify rewrites
+    let scan_plan = scan_blocks(mir_module, remapper, value_to_func_name, &ctx, debug)?;
+
+    if debug {
+        log!(
+            true,
+            "[cf_loop/joinir] Phase 286C-2.1: Scan complete - {} tail calls, {} returns",
+            scan_plan.tail_calls.len(),
+            scan_plan.return_conversions.len()
+        );
+    }
 
     // ===== STAGE 2: PLAN (Generate rewritten blocks) =====
     // TODO Phase 286C-2.1: Extract to plan_rewrites()
@@ -1601,19 +1609,16 @@ pub(super) fn merge_and_rewrite(
         }
     }
 
-    // Phase 286C-2.1: Future orchestrator structure (Step 2 onwards):
+    // Phase 286C-2.1: Step 3 complete - scan_blocks() integrated
+    // Step 4-5 future work: Extract plan/apply logic into separate functions
     //
-    // // Stage 1: Scan - Read-only analysis
-    // let plan = scan_blocks(mir_module, remapper, value_to_func_name, &ctx, debug)?;
+    // Target orchestrator structure:
+    // 1. let plan = scan_blocks(...)?;              // ✅ Done (Step 3)
+    // 2. let blocks = plan_rewrites(plan, &mut ctx)?;  // TODO (Step 4)
+    // 3. apply_rewrites(builder, blocks)?;             // TODO (Step 5)
     //
-    // // Stage 2: Plan - Generate rewritten blocks
-    // let blocks = plan_rewrites(plan, &mut ctx)?;
-    //
-    // // Stage 3: Apply - Mutate builder
-    // apply_rewrites(builder, blocks)?;
-    //
-    // // Build final merge result
-    // Ok(MergeResult { ... })
+    // Current state: Main loop (lines 380-1469) contains both plan and apply logic.
+    // This needs to be separated into 2 stages for clean architecture.
 
     Ok(MergeResult {
         exit_block_id: ctx.exit_block_id,