diff --git a/agents/README.md b/agents/README.md
index d75f596b..fdd34227 100644
--- a/agents/README.md
+++ b/agents/README.md
@@ -10,6 +10,7 @@ The primary workflow is to symlink files from here into each agent runtime/confi
 - `AGENTS.md`: global baseline rules for coding agents.
 - `evals/global-rules.md`: behavioral scenarios for validating changes to the global rules.
 - `install-rules.py`: installs the baseline by creating symlinks in supported agent config dirs.
+- `test_install_rules.py`: regression tests for file preservation and independent target handling.
 - `install-cli.md`: curated CLI install/update command snippets.
 - `install-skills.md`: curated `npx skills` command snippets.
 
@@ -38,6 +39,7 @@ Current targets:
 Behavior:
 
 - Each target is handled independently.
+- Target errors are reported while remaining targets are attempted; any error yields a nonzero exit.
 - Missing destination directories are skipped.
 - Existing regular files are preserved as `.bak` backups (numbered when a backup already exists).
 - Destination links are replaced atomically; a failed link creation leaves the destination intact.
@@ -49,6 +51,12 @@ the global rules source and is not installed by this script.
 Auto-approval controls tool prompting. The global rules still define task authorization, safety, and
 secret handling.
 
+Run installer regression tests without changing installed rules:
+
+```bash
+python3 -B -m unittest discover -s agents -p test_install_rules.py
+```
+
 ## About `install-cli.md` and `install-skills.md`
 
 Use them as snippet libraries:
diff --git a/agents/install-rules.py b/agents/install-rules.py
index bf898224..a257f9da 100644
--- a/agents/install-rules.py
+++ b/agents/install-rules.py
@@ -47,12 +47,21 @@ def main() -> int:
     opencode_dir = xdg_config_home / "opencode"
     claude_dir = Path("~/.claude").expanduser()
     agents_dir = Path("~/.agents").expanduser()
-    install_one(codex_dir, agents_file, "AGENTS.md")
-    install_one(opencode_dir, agents_file, "AGENTS.md")
-    install_one(claude_dir, agents_file, "CLAUDE.md")
-    install_one(agents_dir, agents_file, "AGENTS.md")
+    targets = (
+        (codex_dir, "AGENTS.md"),
+        (opencode_dir, "AGENTS.md"),
+        (claude_dir, "CLAUDE.md"),
+        (agents_dir, "AGENTS.md"),
+    )
+    failed = False
+    for target_dir, target_name in targets:
+        try:
+            install_one(target_dir, agents_file, target_name)
+        except OSError as error:
+            print(f"failed  {target_dir / target_name}: {error}", file=sys.stderr)
+            failed = True
 
-    return 0
+    return 1 if failed else 0
 
 
 if __name__ == "__main__":
diff --git a/agents/test_install_rules.py b/agents/test_install_rules.py
index 2f1c41cf..6f90aca5 100644
--- a/agents/test_install_rules.py
+++ b/agents/test_install_rules.py
@@ -1,4 +1,5 @@
 import importlib.util
+import io
 import tempfile
 import unittest
 from pathlib import Path
@@ -13,6 +14,22 @@ spec.loader.exec_module(installer)
 
 
 class InstallRulesTests(unittest.TestCase):
+    def test_target_failure_does_not_stop_remaining_targets(self):
+        with (
+            patch.object(
+                installer, "install_one", side_effect=[PermissionError("denied"), None, None, None]
+            ) as install,
+            patch("sys.stderr", new_callable=io.StringIO) as stderr,
+        ):
+            self.assertEqual(installer.main(), 1)
+            self.assertEqual(install.call_count, 4)
+            self.assertIn("denied", stderr.getvalue())
+
+    def test_successful_targets_return_success(self):
+        with patch.object(installer, "install_one") as install:
+            self.assertEqual(installer.main(), 0)
+            self.assertEqual(install.call_count, 4)
+
     def test_existing_file_is_backed_up_without_overwriting_backup(self):
         with tempfile.TemporaryDirectory() as directory:
             root = Path(directory)