diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index 67f711b35..24458017c 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -3103,7 +3103,11 @@ For more help on a command:
 
         elif action == "export":
             if args.session_id:
-                data = db.export_session(args.session_id)
+                resolved_session_id = db.resolve_session_id(args.session_id)
+                if not resolved_session_id:
+                    print(f"Session '{args.session_id}' not found.")
+                    return
+                data = db.export_session(resolved_session_id)
                 if not data:
                     print(f"Session '{args.session_id}' not found.")
                     return
@@ -3118,13 +3122,17 @@ For more help on a command:
                 print(f"Exported {len(sessions)} sessions to {args.output}")
 
         elif action == "delete":
+            resolved_session_id = db.resolve_session_id(args.session_id)
+            if not resolved_session_id:
+                print(f"Session '{args.session_id}' not found.")
+                return
             if not args.yes:
-                confirm = input(f"Delete session '{args.session_id}' and all its messages? [y/N] ")
+                confirm = input(f"Delete session '{resolved_session_id}' and all its messages? [y/N] ")
                 if confirm.lower() not in ("y", "yes"):
                     print("Cancelled.")
                     return
-            if db.delete_session(args.session_id):
-                print(f"Deleted session '{args.session_id}'.")
+            if db.delete_session(resolved_session_id):
+                print(f"Deleted session '{resolved_session_id}'.")
             else:
                 print(f"Session '{args.session_id}' not found.")
 
@@ -3140,10 +3148,14 @@ For more help on a command:
             print(f"Pruned {count} session(s).")
 
         elif action == "rename":
+            resolved_session_id = db.resolve_session_id(args.session_id)
+            if not resolved_session_id:
+                print(f"Session '{args.session_id}' not found.")
+                return
             title = " ".join(args.title)
             try:
-                if db.set_session_title(args.session_id, title):
-                    print(f"Session '{args.session_id}' renamed to: {title}")
+                if db.set_session_title(resolved_session_id, title):
+                    print(f"Session '{resolved_session_id}' renamed to: {title}")
                 else:
                     print(f"Session '{args.session_id}' not found.")
             except ValueError as e:
diff --git a/hermes_state.py b/hermes_state.py
index 8945e195d..3f4715067 100644
--- a/hermes_state.py
+++ b/hermes_state.py
@@ -249,6 +249,32 @@ class SessionDB:
         row = cursor.fetchone()
         return dict(row) if row else None
 
+    def resolve_session_id(self, session_id_or_prefix: str) -> Optional[str]:
+        """Resolve an exact or uniquely prefixed session ID to the full ID.
+
+        Returns the exact ID when it exists. Otherwise treats the input as a
+        prefix and returns the single matching session ID if the prefix is
+        unambiguous. Returns None for no matches or ambiguous prefixes.
+        """
+        exact = self.get_session(session_id_or_prefix)
+        if exact:
+            return exact["id"]
+
+        escaped = (
+            session_id_or_prefix
+            .replace("\\", "\\\\")
+            .replace("%", "\\%")
+            .replace("_", "\\_")
+        )
+        cursor = self._conn.execute(
+            "SELECT id FROM sessions WHERE id LIKE ? ESCAPE '\\' ORDER BY started_at DESC LIMIT 2",
+            (f"{escaped}%",),
+        )
+        matches = [row["id"] for row in cursor.fetchall()]
+        if len(matches) == 1:
+            return matches[0]
+        return None
+
     # Maximum length for session titles
     MAX_TITLE_LENGTH = 100
 
diff --git a/tests/hermes_cli/test_sessions_delete.py b/tests/hermes_cli/test_sessions_delete.py
new file mode 100644
index 000000000..6f6d359b4
--- /dev/null
+++ b/tests/hermes_cli/test_sessions_delete.py
@@ -0,0 +1,64 @@
+import sys
+
+
+def test_sessions_delete_accepts_unique_id_prefix(monkeypatch, capsys):
+    import hermes_cli.main as main_mod
+    import hermes_state
+
+    captured = {}
+
+    class FakeDB:
+        def resolve_session_id(self, session_id):
+            captured["resolved_from"] = session_id
+            return "20260315_092437_c9a6ff"
+
+        def delete_session(self, session_id):
+            captured["deleted"] = session_id
+            return True
+
+        def close(self):
+            captured["closed"] = True
+
+    monkeypatch.setattr(hermes_state, "SessionDB", lambda: FakeDB())
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        ["hermes", "sessions", "delete", "20260315_092437_c9a6", "--yes"],
+    )
+
+    main_mod.main()
+
+    output = capsys.readouterr().out
+    assert captured == {
+        "resolved_from": "20260315_092437_c9a6",
+        "deleted": "20260315_092437_c9a6ff",
+        "closed": True,
+    }
+    assert "Deleted session '20260315_092437_c9a6ff'." in output
+
+
+def test_sessions_delete_reports_not_found_when_prefix_is_unknown(monkeypatch, capsys):
+    import hermes_cli.main as main_mod
+    import hermes_state
+
+    class FakeDB:
+        def resolve_session_id(self, session_id):
+            return None
+
+        def delete_session(self, session_id):
+            raise AssertionError("delete_session should not be called when resolution fails")
+
+        def close(self):
+            pass
+
+    monkeypatch.setattr(hermes_state, "SessionDB", lambda: FakeDB())
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        ["hermes", "sessions", "delete", "missing-prefix", "--yes"],
+    )
+
+    main_mod.main()
+
+    output = capsys.readouterr().out
+    assert "Session 'missing-prefix' not found." in output
diff --git a/tests/test_hermes_state.py b/tests/test_hermes_state.py
index 81e922c7f..d77247936 100644
--- a/tests/test_hermes_state.py
+++ b/tests/test_hermes_state.py
@@ -361,6 +361,24 @@ class TestDeleteAndExport:
     def test_delete_nonexistent(self, db):
         assert db.delete_session("nope") is False
 
+    def test_resolve_session_id_exact(self, db):
+        db.create_session(session_id="20260315_092437_c9a6ff", source="cli")
+        assert db.resolve_session_id("20260315_092437_c9a6ff") == "20260315_092437_c9a6ff"
+
+    def test_resolve_session_id_unique_prefix(self, db):
+        db.create_session(session_id="20260315_092437_c9a6ff", source="cli")
+        assert db.resolve_session_id("20260315_092437_c9a6") == "20260315_092437_c9a6ff"
+
+    def test_resolve_session_id_ambiguous_prefix_returns_none(self, db):
+        db.create_session(session_id="20260315_092437_c9a6aa", source="cli")
+        db.create_session(session_id="20260315_092437_c9a6bb", source="cli")
+        assert db.resolve_session_id("20260315_092437_c9a6") is None
+
+    def test_resolve_session_id_escapes_like_wildcards(self, db):
+        db.create_session(session_id="20260315_092437_c9a6ff", source="cli")
+        db.create_session(session_id="20260315X092437_c9a6ff", source="cli")
+        assert db.resolve_session_id("20260315_092437") == "20260315_092437_c9a6ff"
+
     def test_export_session(self, db):
         db.create_session(session_id="s1", source="cli", model="test")
         db.append_message("s1", role="user", content="Hello")