diff --git a/App/lib/Phase/Phase2/__init__.vp b/App/lib/Phase/Phase2/__init__.vp
index ca8fd8d..2134031 100644
--- a/App/lib/Phase/Phase2/__init__.vp
+++ b/App/lib/Phase/Phase2/__init__.vp
@@ -1433,7 +1433,7 @@ def RunMultiFileProject(mb: memhub.MemBuddy*, source_dir: str, temp_dir: str, ou
             string.strcpy(final_obj_paths, main_obj_path)
             fop_pos = mlen
 
-        # Merge the App non-main modules' .obj (obj_paths, space-separated) compiled by Phase B/B+.
+        # Merge the App non-main modules' .obj (obj_paths, space-separated) compiled by Phase B/B+.
         # final_obj_paths must include main_obj + reachable includes + App deps, else linking hits undefined symbols.
         if obj_pos > 0:
             if fop_pos + obj_pos + 1 < OBJ_PATHS_SIZE + 512:
diff --git a/App/lib/Projectrans/Config.vp b/App/lib/Projectrans/Config.vp
index ea5aa7a..ddb47a4 100644
--- a/App/lib/Projectrans/Config.vp
+++ b/App/lib/Projectrans/Config.vp
@@ -354,19 +354,17 @@ def resolve_paths(project_dir: str) -> int:
     SourceDir = _join_path(SourceDir, project_dir)
     BuildDir = _join_path(BuildDir, project_dir)
 
-    # TempDir = {BuildDir}/temp (single-track MLIR always appends the _mlir isolation suffix)
+    # TempDir = {BuildDir}/temp; OutputDir = {BuildDir}/output
     if BuildDir is not None:
         bd_len: sizet = string.strlen(BuildDir)
-        suf_dir: str = mlir_dir_suffix()
-        suf_dir_len: sizet = string.strlen(suf_dir)
-        temp_buf: str = _mbuddy.alloc(bd_len + suf_dir_len + 8)
+        temp_buf: str = _mbuddy.alloc(bd_len + 8)
         if temp_buf is not None:
-            viperlib.snprintf(temp_buf, bd_len + suf_dir_len + 8, "%s/temp%s", BuildDir, suf_dir)
+            viperlib.snprintf(temp_buf, bd_len + 8, "%s/temp", BuildDir)
             TempDir = temp_buf
         # OutputDir = {BuildDir}/output
-        output_buf: str = _mbuddy.alloc(bd_len + suf_dir_len + 8)
+        output_buf: str = _mbuddy.alloc(bd_len + 8)
         if output_buf is not None:
-            viperlib.snprintf(output_buf, bd_len + suf_dir_len + 8, "%s/output%s", BuildDir, suf_dir)
+            viperlib.snprintf(output_buf, bd_len + 8, "%s/output", BuildDir)
             OutputDir = output_buf
 
     # includes paths may be of the form ../includes, resolved against project_dir.
@@ -545,10 +543,13 @@ def get_includes_binary_dir() -> str:
     return buf
 
 
-# Directory isolation suffix for single-track MLIR.
-# Emitter is always mlirlite, so the suffix is "_mlir": Temp/Output/includes caches live under *_mlir, separate from old LLVM caches.
+# Directory isolation suffix for the includes binary cache only.
+# TempDir/OutputDir are plain {BuildDir}/temp and {BuildDir}/output (same layout as TPC and as
+# the project scripts expect). The includes cache keeps "_mlir": it holds MLIR-era artifacts
+# (sha1 subdirectories) while TPC's includes cache at {IncludesDir}.binary/ holds flat
+# "<sha1>.<triple>.pic.obj" files, so sharing one directory would mix the two layouts.
 def mlir_dir_suffix() -> str:
-    """Directory isolation suffix for the MLIR backend (always "_mlir")."""
+    """Directory isolation suffix for the includes cache of the MLIR backend (always "_mlir")."""
     return "_mlir"