diff --git a/.gitignore b/.gitignore
index 385de5e..f8197c1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,10 @@ engine/*.pak
 engine/*.dll
 engine/argus316/
 engine/omicron/
+# scratch mod dirs: lab runs need a -game dir under engine/, and a
+# git add -A has twice swept one into a commit. Only argus/ ships.
+engine/*/
+!engine/argus/
 engine/qconsole.log
 
 # id-derived coloured model staging (regenerate from LibreQuake for
diff --git a/engine/argsession/autoexec.cfg b/engine/argsession/autoexec.cfg
deleted file mode 100644
index 0d36bf0..0000000
--- a/engine/argsession/autoexec.cfg
+++ /dev/null
@@ -1,2 +0,0 @@
-sv_protocol 15
-max_edicts 600
diff --git a/engine/argsession/progs.dat b/engine/argsession/progs.dat
deleted file mode 100644
index 8fc28a9..0000000
Binary files a/engine/argsession/progs.dat and /dev/null differ
diff --git a/engine/argus/progs.dat b/engine/argus/progs.dat
index ed4c600..8fc28a9 100644
Binary files a/engine/argus/progs.dat and b/engine/argus/progs.dat differ
diff --git a/game/argus/progs.dat b/game/argus/progs.dat
index ed4c600..8fc28a9 100644
Binary files a/game/argus/progs.dat and b/game/argus/progs.dat differ
diff --git a/tools/argus_mcp/src/backup.rs b/tools/argus_mcp/src/backup.rs
index d9aeec1..cc44805 100644
--- a/tools/argus_mcp/src/backup.rs
+++ b/tools/argus_mcp/src/backup.rs
@@ -358,16 +358,42 @@ mod tests {
             "an out-of-tree install must get an indexed key, got {keys:?}"
         );
 
+        // take_backup only READS the install paths, so it is safe here.
+        // restore_backup is deliberately NOT called: install_paths()
+        // includes the rerelease Saved Games copy, which lives under
+        // USERPROFILE and not under this test's temp root, so restoring
+        // would write to a real install on the developer's machine -
+        // the exact class #222 was about, and it made this test flaky
+        // besides. The defect #215 describes is the manifest KEY
+        // collision, and the manifest is what we check.
         let taken = take_backup(&cfg);
         assert!(taken.ok, "{taken:?}");
-        fs::write(outside.join("argus/progs.dat"), b"CLOBBERED").unwrap();
-        let r = restore_backup(&cfg, &taken.id).unwrap();
-        assert!(r.ok, "{r:?}");
-        assert_eq!(
-            fs::read(outside.join("argus/progs.dat")).unwrap(),
-            b"OUTSIDE",
-            "the out-of-tree install must come back"
+        let man = read_manifest(&backups_dir(&cfg).join(&taken.id))
+            .expect("manifest written");
+        let progs: Vec<&BackupFile> = man
+            .files
+            .iter()
+            .filter(|f| f.rel.ends_with("progs.dat"))
+            .collect();
+        let mut rels: Vec<&str> = progs.iter().map(|f| f.rel.as_str()).collect();
+        rels.sort();
+        let uniq = {
+            let mut r = rels.clone();
+            r.dedup();
+            r.len()
+        };
+        assert_eq!(rels.len(), uniq, "progs.dat entries collided: {rels:?}");
+        assert!(
+            progs.iter().any(|f| f.restore_to.contains("steam")),
+            "the out-of-tree install must be in the manifest, got {rels:?}"
         );
+        for f in &progs {
+            assert!(
+                backups_dir(&cfg).join(&taken.id).join(&f.rel).is_file(),
+                "manifest names {} but no file was copied",
+                f.rel
+            );
+        }
         let _ = fs::remove_dir_all(&base);
     }
 }
diff --git a/tools/argus_mcp/src/gui.rs b/tools/argus_mcp/src/gui.rs
index 724b322..9ffb12a 100644
--- a/tools/argus_mcp/src/gui.rs
+++ b/tools/argus_mcp/src/gui.rs
@@ -305,8 +305,7 @@ fn write_response(stream: &mut TcpStream, resp: &Response) -> Result<(), String>
 /// progs.dat. A page on any other origin could reach them as a simple
 /// cross-site request: text/plain body, no preflight, no token. Require
 /// a same-origin Host, no cross-origin Origin, and real JSON.
-fn post_allowed(req: &Request) -> Result<(), Response> {
-    let port = GUI_PORT.load(std::sync::atomic::Ordering::Relaxed);
+fn post_allowed(req: &Request, port: u16) -> Result<(), Response> {
     let host = req.headers.get("host").map(|s| s.as_str()).unwrap_or("");
     let want_a = format!("127.0.0.1:{port}");
     let want_b = format!("localhost:{port}");
@@ -340,8 +339,16 @@ fn post_allowed(req: &Request) -> Result<(), Response> {
 }
 
 fn route(req: &Request) -> Response {
+    route_at(req, GUI_PORT.load(std::sync::atomic::Ordering::Relaxed))
+}
+
+/// The bound port is passed in rather than read from a global: the POST
+/// guard is a security check and should not depend on hidden process
+/// state, and the lib tests run concurrently in one process, which made
+/// a global-reading version flake.
+fn route_at(req: &Request, port: u16) -> Response {
     if req.method == "POST" {
-        if let Err(r) = post_allowed(req) {
+        if let Err(r) = post_allowed(req, port) {
             return r;
         }
     }
@@ -888,13 +895,16 @@ mod tests {
         for (k, v) in headers {
             h.insert(k.to_string(), v.to_string());
         }
-        route(&Request {
-            method: "POST".into(),
-            path: path.into(),
-            query: HashMap::new(),
-            body: b"{}".to_vec(),
-            headers: h,
-        })
+        route_at(
+            &Request {
+                method: "POST".into(),
+                path: path.into(),
+                query: HashMap::new(),
+                body: b"{}".to_vec(),
+                headers: h,
+            },
+            7420,
+        )
     }
 
     // #214: these endpoints rewrite the source tree and every installed
@@ -902,7 +912,6 @@ mod tests {
     // cross-site request: text/plain body, no preflight, no token.
     #[test]
     fn post_endpoints_refuse_other_origins() {
-        GUI_PORT.store(7420, std::sync::atomic::Ordering::Relaxed);
         let ok_headers = [
             ("host", "127.0.0.1:7420"),
             ("content-type", "application/json"),