diff --git a/home/progs/pi.nix b/home/progs/pi.nix
index e9fa45b..2dba5ac 100644
--- a/home/progs/pi.nix
+++ b/home/progs/pi.nix
@@ -203,9 +203,15 @@ in
       mcpServers = {
         ghidra = {
           command = lib.getExe pyghidra-mcp;
+          # --project-path defaults to the relative ./pyghidra_mcp_projects, which
+          # pyghidra-mcp materializes inside whatever cwd OMP launched it from.
+          # Pin it to a stable cache location so opening any directory doesn't
+          # litter it with a project folder.
           args = [
             "--transport"
             "stdio"
+            "--project-path"
+            "${config.home.homeDirectory}/.cache/pyghidra-mcp"
           ];
         };
       };