Several sessions of one app: a session's working folder names its agent when that agent runs in the same app (MCP server and hooks), an i_am tool binds a session explicitly, the doctor checks second sessions against their app's install, and an agent that left the roster can still be uninstalled

tests/test_core.py

@@ -340,6 +340,18 @@ class Projects(unittest.TestCase):
             with self.assertRaises(projects.ProjectError):
                 projects.project_from_dict(bad, home=self.dir)
 
+    def test_session_identity_for_two_sessions_of_one_app(self):
+        made = projects.project_from_dict({
+            "name": "pair", "identities": {"wt-codex": "Codex", "wt-codex2": "Codex2", "wt-deepseek": "DeepSeek"},
+            "agents": [{"name": "Codex", "host": "codex"}, {"name": "Codex2", "host": "codex"},
+                       {"name": "DeepSeek", "host": "deepseek"}, {"name": "User", "kind": "human"}]}, home=self.dir)
+        two = self.dir / "wt-codex2" / "src"
+        two.mkdir(parents=True)
+        self.assertEqual(made.session_identity("Codex", two), "Codex2")             # same app: the folder decides
+        self.assertEqual(made.session_identity("Codex", self.dir), "Codex")         # no folder match: installed one
+        self.assertEqual(made.session_identity("DeepSeek", two), "DeepSeek")        # another app's folder: ignored
+        self.assertEqual(made.session_identity(None, two), "Codex2")                # nothing pinned: the folder
+
     def test_resolution_order_and_identities(self):
         made = make_home(self.dir, names=("first", "second"))
         self.assertEqual(projects.resolve(home=self.dir, cwd=self.dir).name, "first")      # home default