diff --git a/conductor/tracks/result_migration_baseline_cleanup_20260620/state.toml b/conductor/tracks/result_migration_baseline_cleanup_20260620/state.toml
index 32c4f761..847d2e0f 100644
--- a/conductor/tracks/result_migration_baseline_cleanup_20260620/state.toml
+++ b/conductor/tracks/result_migration_baseline_cleanup_20260620/state.toml
@@ -31,7 +31,7 @@ phase_9 = { status = "completed", checkpointsha = "84b7a693", name = "ai_client
 phase_10 = { status = "completed", checkpointsha = "40a60e63", name = "ai_client Batch B (broad-catch; 9 sites migrated via 7 helpers; BC 9->0)" }
 phase_11 = { status = "completed", checkpointsha = "26ebbf78", name = "ai_client silent-swallow (11 sites; CRITICAL anti-sliming; SS 11->0, UNCLEAR 0->0)" }
 phase_12 = { status = "completed", checkpointsha = "b95601e9", name = "ai_client rethrow classification (6 sites; 4 Pattern 1 fixes + 1 Result migration + 1 known limitation)" }
-phase_13 = { status = "pending", checkpointsha = "", name = "rag_engine migration (1 SS + 5 BC + 3 RETHROW = 9 sites)" }
+phase_13 = { status = "completed", checkpointsha = "1e323cae", name = "rag_engine migration (9 sites: 1 SS + 5 BC + 3 RETHROW; migration-target 9->0)" }
 phase_14 = { status = "pending", checkpointsha = "", name = "Audit gate + end-of-track report (5 tasks; --include-baseline --strict exits 0; 11/11 tiers PASS; campaign 100% complete)" }
 
 [tasks]
@@ -168,17 +168,17 @@ t12_7 = { status = "completed", commit_sha = "", description = "SKIPPED: was 7 s
 t12_8 = { status = "in_progress", commit_sha = "", description = "Add Phase 12 invariant test; Phase 12 checkpoint" }
 
 # Phase 13: rag_engine migration (9 sites)
-t13_0 = { status = "pending", commit_sha = "", description = "Phase 13 styleguide re-read + ack commit" }
-t13_1 = { status = "pending", commit_sha = "", description = "Migrate broad-catch site 1" }
-t13_2 = { status = "pending", commit_sha = "", description = "Migrate broad-catch site 2" }
-t13_3 = { status = "pending", commit_sha = "", description = "Migrate broad-catch site 3" }
-t13_4 = { status = "pending", commit_sha = "", description = "Migrate broad-catch site 4" }
-t13_5 = { status = "pending", commit_sha = "", description = "Migrate broad-catch site 5" }
-t13_6 = { status = "pending", commit_sha = "", description = "Migrate silent-swallow site 6" }
-t13_7 = { status = "pending", commit_sha = "", description = "Classify or migrate rethrow site 7" }
-t13_8 = { status = "pending", commit_sha = "", description = "Classify or migrate rethrow site 8" }
-t13_9 = { status = "pending", commit_sha = "", description = "Classify or migrate rethrow site 9" }
-t13_10 = { status = "pending", commit_sha = "", description = "Add Phase 13 invariant test; Phase 13 checkpoint" }
+t13_0 = { status = "completed", commit_sha = "8321608", description = "Phase 13 styleguide re-read + ack commit" }
+t13_1 = { status = "completed", commit_sha = "f322052c", description = "Migrate BC site 1 (narrow 'except Exception' to (ImportError, AttributeError))" }
+t13_2 = { status = "completed", commit_sha = "7b3d7237", description = "Migrate BC site 2 (_chunk_code to Result)" }
+t13_3 = { status = "completed", commit_sha = "ee50c265", description = "Migrate BC sites 3+4 + SS 6 (3 index_file helpers)" }
+t13_4 = { status = "completed", commit_sha = "ee50c265", description = "Migrate BC site 4 (combined with site 3 in index_file batch)" }
+t13_5 = { status = "completed", commit_sha = "1e323cae", description = "Migrate BC site 5 (_async_search_mcp JSON parse to Result)" }
+t13_6 = { status = "completed", commit_sha = "ee50c265", description = "Migrate SS site 6 (combined with sites 3+4)" }
+t13_7 = { status = "completed", commit_sha = "", description = "RETHROW sites (Pattern 1/3 documented as known audit limitation; not migrated)" }
+t13_8 = { status = "completed", commit_sha = "", description = "RETHROW sites (Pattern 1/3 known limitation)" }
+t13_9 = { status = "completed", commit_sha = "", description = "RETHROW sites (Pattern 1/3 known limitation)" }
+t13_10 = { status = "in_progress", commit_sha = "", description = "Add Phase 13 invariant test; Phase 13 checkpoint" }
 
 # Phase 14: Audit gate + end-of-track report (5 tasks)
 t14_1 = { status = "pending", commit_sha = "", description = "Run audit --include-baseline --strict; verify exit 0" }
@@ -201,7 +201,7 @@ phase_9_complete = true
 phase_10_complete = true
 phase_11_complete = true
 phase_12_complete = true
-phase_13_complete = false
+phase_13_complete = true
 phase_14_complete = false
 mcp_client_broad_catch_zero = false
 mcp_client_silent_swallow_zero = false
diff --git a/tests/tier2/phase13_invariant_test.py b/tests/tier2/phase13_invariant_test.py
new file mode 100644
index 00000000..b3cb8024
--- /dev/null
+++ b/tests/tier2/phase13_invariant_test.py
@@ -0,0 +1,69 @@
+"""Phase 13 invariant tests (GREEN).
+
+9 migration-target sites addressed:
+- Site 1 (BC L33): narrowed 'except Exception' to (ImportError, AttributeError)
+- Site 2 (BC L224): migrated _chunk_code to Result (helper _chunk_code_result)
+- Site 3 (BC L247): extracted _get_file_mtime_result helper
+- Site 4 (BC L261): extracted _read_file_content_result helper
+- Site 5 (BC L290): extracted _parse_search_response_result helper (module-level)
+- Site 6 (SS L255): extracted _check_existing_index_result helper
+- Sites 7 (RETHROW L29/L32/L33/L36): follow Pattern 1/3; documented as known audit limitation
+"""
+import sys
+sys.path.insert(0, ".")
+
+
+def test_phase13_rag_engine_migration_target_zero():
+    """After Phase 13: rag_engine migration-target count is 0 (was 9)."""
+    import json
+    import subprocess
+    r = subprocess.run(
+        ["uv", "run", "python", "scripts/audit_exception_handling.py",
+         "--include-baseline", "--json"],
+        capture_output=True, text=True
+    )
+    data = json.loads(r.stdout)
+    files = {f["filename"]: f for f in data["files"]}
+    rag = files["src\\rag_engine.py"]
+    migration = sum(1 for x in rag["findings"] if x["category"] in (
+        "INTERNAL_BROAD_CATCH", "INTERNAL_SILENT_SWALLOW", "INTERNAL_OPTIONAL_RETURN", "UNCLEAR"
+    ))
+    assert migration == 0, f"expected rag_engine migration-target=0, got {migration}"
+
+
+def test_phase13_rag_engine_rethrow_strict_acceptable():
+    """rag_engine RETHROW sites follow Pattern 1/3 of styleguide (strict mode accepts)."""
+    import json
+    import subprocess
+    r = subprocess.run(
+        ["uv", "run", "python", "scripts/audit_exception_handling.py", "--strict"],
+        capture_output=True, text=True
+    )
+    # The strict mode only fails on violations (BC/SS/OO/UNCLEAR), not RETHROW.
+    # If rag_engine is contributing violations, fail.
+    assert "src\\\\rag_engine.py" not in r.stdout or "VIOLATION" not in r.stdout.split("src\\\\rag_engine.py")[1].split("\n\n")[0] if "src\\\\rag_engine.py" in r.stdout else True
+
+
+def test_phase13_all_helpers_exist():
+    """All 5 new _result helpers must exist."""
+    import src.rag_engine
+    # Class methods (4): _chunk_code_result, _get_file_mtime_result,
+    # _check_existing_index_result, _read_file_content_result
+    for name in ("_chunk_code_result", "_get_file_mtime_result",
+                 "_check_existing_index_result", "_read_file_content_result"):
+        assert hasattr(src.rag_engine.RAGEngine, name), f"{name} method missing"
+    # Module-level (1): _parse_search_response_result
+    assert hasattr(src.rag_engine, "_parse_search_response_result"), \
+        "_parse_search_response_result module-level helper missing"
+
+
+def test_phase13_legacy_functions_preserved():
+    """All legacy functions must still exist + be callable."""
+    import src.rag_engine
+    # Class methods
+    for name in ("_chunk_code", "_search_mcp", "search", "delete_documents",
+                 "get_all_indexed_paths", "delete_documents_by_path", "index_file"):
+        assert hasattr(src.rag_engine.RAGEngine, name), f"{name} method missing"
+    # Module-level
+    for name in ("_get_sentence_transformers", "_get_google_genai", "_get_chromadb"):
+        assert hasattr(src.rag_engine, name), f"{name} module-level function missing"
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