diff --git a/build.py b/build.py
index b85af31a..82f86674 100755
--- a/build.py
+++ b/build.py
@@ -130,7 +130,7 @@ def get_build_mode_from_command_line():
     """
     mode = sys.argv[1].lower() if len(sys.argv) > 1 else 'all'
     if mode in ["cpp", "cxx"]: mode = "c++"
-    if not mode in ["all", "c++", "clean", "experiment"]:
+    if not mode in ["all", "c++", "clean", "ccjson"]:
         sys.exit(f"Invalid build mode: {mode}")
     return mode
 
@@ -294,22 +294,29 @@ def build_intellisense_database_for_clangd():
     based on clangd how to compile each source file.
     This also installs a .clangd file in the UnrealEngine directory.
     """
-    mods1 = Path(f"{INTEGRATION}/Intermediate/Build/{OS}").rglob("UnrealEditor/{DEBUG}/**/Module.*.o.rsp")
-    mods2 = Path(f"{UNREALENGINE}/Engine/Intermediate/Build/{OS}").rglob("UnrealEditor/Development/**/Module.*.o.rsp")
-    mods = list(mods1) + list(mods2)
+    # Find clang compiler.
     clangs = list(Path(f"{UNREALENGINE}/Engine/Extras/ThirdPartyNotUE/SDKs").rglob("*-linux-gnu/bin/clang++"))
     if len(clangs) != 1: sys.exit("Couldn't identify correct clang++ compiler in UnrealEngine thirdparty directory")
     clang = str(clangs[0])
-    ccjson = json.loads(Path(f"{INTEGRATION}/luprex/build/{OS}/compile_commands.json").read_text())
-    ccdir = f"{UNREALENGINE}/Engine/Source";
-    for mod in mods:
+    # Build the table of source files and RSP files.
+    mods1 = Path(f"{INTEGRATION}/Intermediate/Build/{OS}").rglob(f"UnrealEditor/{DEBUG}/**/Module.*.o.rsp")
+    mods2 = Path(f"{UNREALENGINE}/Engine/Intermediate/Build/{OS}").rglob("UnrealEditor/Development/**/Module.*.o.rsp")
+    cpp_to_rsp = {}
+    for mod in itertools.chain(mods1, mods2):
         rsp = str(mod)
-        cpp = rsp.removesuffix(".o.rsp")
+        cpp = os.path.abspath(rsp.removesuffix(".o.rsp"))
+        cpp_to_rsp[cpp] = rsp
+        for subfile in cpp_files_included_by(cpp):
+            abs = os.path.abspath(os.path.join(f"{UNREALENGINE}/Engine/Source", subfile))
+            cpp_to_rsp[abs] = rsp
+    # Read the luprex compile commands database.
+    ccjson = json.loads(Path(f"{INTEGRATION}/luprex/build/{OS}/compile_commands.json").read_text())
+    # Generate the new commands
+    ccdir = f"{UNREALENGINE}/Engine/Source";
+    for cpp in sorted(cpp_to_rsp.keys()):
+        rsp = cpp_to_rsp[cpp]
         args = [clang, "@"+rsp]
         ccjson.append({ "file" : cpp, "arguments":args, "directory":ccdir })
-        for subfile in cpp_files_included_by(cpp):
-            abs = os.path.join(f"{UNREALENGINE}/Engine", subfile)
-            ccjson.append({ "file" : abs, "arguments":args, "directory":ccdir })
     Path(f"{INTEGRATION}/.vscode/compile_commands.json").write_text(json.dumps(ccjson, indent=2))
 
 
@@ -348,6 +355,9 @@ CONFIG = autodetect_system_config()
 store_system_config_in_globals(CONFIG)
 os.chdir(f"{INTEGRATION}/EnginePatches")
 
+if MODE == "ccjson":
+    build_intellisense_database_for_clangd()
+
 if MODE == "all":
     unzip_unreal_engine_and_apply_patch()
     generate_buildconfiguration_xml()