diff --git a/src/envault/auth.py b/src/envault/auth.py
index 05bfd58..1155ea9 100644
--- a/src/envault/auth.py
+++ b/src/envault/auth.py
@@ -16,6 +16,7 @@
 import time
 from typing import Any
 from urllib.error import URLError
+from urllib.parse import urlencode
 from urllib.request import Request, urlopen
 
 
@@ -164,7 +165,7 @@ def _introspect(self, token: str) -> AuthResult:
         import base64
 
         url = f"{self._provider_url}/introspect"
-        body = f"token={token}".encode()
+        body = urlencode({"token": token}).encode()
         headers: dict[str, str] = {
             "Content-Type": "application/x-www-form-urlencoded",
         }
diff --git a/src/envault/backup.py b/src/envault/backup.py
index 228caa3..3f83646 100644
--- a/src/envault/backup.py
+++ b/src/envault/backup.py
@@ -92,16 +92,32 @@ def _get_backup_dir(project_dir: Path | str = ".") -> Path:
 
 
 def _load_manifest(backup_dir: Path) -> list[BackupEntry]:
-    """Load the backup manifest from disk."""
+    """Load the backup manifest from disk.
+
+    Skips individual corrupt entries rather than discarding the entire
+    manifest, preserving valid backups when one entry is malformed.
+    """
     manifest_path = backup_dir / BACKUP_MANIFEST
     if not manifest_path.exists():
         return []
     try:
         data = json.loads(manifest_path.read_text(encoding="utf-8"))
-        return [BackupEntry.from_dict(entry) for entry in data]
-    except (json.JSONDecodeError, KeyError):
+    except json.JSONDecodeError:
         return []
 
+    if not isinstance(data, list):
+        return []
+
+    entries: list[BackupEntry] = []
+    for entry in data:
+        if not isinstance(entry, dict):
+            continue
+        try:
+            entries.append(BackupEntry.from_dict(entry))
+        except (KeyError, TypeError):
+            continue
+    return entries
+
 
 def _save_manifest(backup_dir: Path, entries: list[BackupEntry]) -> None:
     """Save the backup manifest to disk."""
diff --git a/src/envault/serve.py b/src/envault/serve.py
index d8ce597..fe47665 100644
--- a/src/envault/serve.py
+++ b/src/envault/serve.py
@@ -19,7 +19,6 @@
 import base64
 import json
 import os
-import secrets as _secrets
 import time
 from http.server import BaseHTTPRequestHandler, HTTPServer
 from pathlib import Path
@@ -69,36 +68,6 @@ def _send_error(self, status: int, message: str) -> None:
         """Send a JSON error payload."""
         self._send_json({"error": message}, status=status)
 
-    def _check_auth(self) -> bool:
-        """Validate the Bearer token if API auth is enabled.
-
-        Returns True if the request is authorized (or auth is disabled).
-        Returns False if auth is required but missing/invalid (and sends 401).
-        """
-        if not self.api_key:
-            # Auth not configured — allow all requests
-            return True
-
-        auth_header = self.headers.get("Authorization", "")
-        if not auth_header:
-            self._send_error(401, "Unauthorized: valid Bearer token required")
-            return False
-
-        token = auth_header[len("Bearer ") :] if auth_header.startswith("Bearer ") else auth_header
-        if not token or not token.strip():
-            self._send_error(401, "Unauthorized: valid Bearer token required")
-            return False
-
-        if (
-            _secrets.compare_digest(token.strip(), self.api_key)
-            if self.api_key
-            else _secrets.compare_digest(token.strip(), "")
-        ):
-            return True
-
-        self._send_error(401, "Unauthorized: valid Bearer token required")
-        return False
-
     # ── Routing ──────────────────────────────────────────────────────────────
 
     def _check_bearer_token(self) -> bool:
@@ -330,6 +299,9 @@ def do_GET(self) -> None:  # noqa: N802 -- stdlib naming convention
         if path == "/health":
             # /health is always accessible (useful for load balancers)
             self._handle_health()
+        elif path == "/auth/info":
+            # /auth/info is always accessible so clients can discover auth methods
+            self._handle_auth_info()
         elif path == "/secrets":
             if not self._check_auth():
                 return
diff --git a/src/envault/stores/__init__.py b/src/envault/stores/__init__.py
index 7080641..eee5dcc 100644
--- a/src/envault/stores/__init__.py
+++ b/src/envault/stores/__init__.py
@@ -346,7 +346,10 @@ def _api_post(self, path: str, data: dict) -> bool:
         return resp.status_code in (200, 201)
 
     def get(self, key: str) -> str | None:
-        items = self._api_get(f"/v1/vaults/{self.vault_id}/items?filter=title%20eq%20%22{key}%22")
+        from urllib.parse import quote
+
+        encoded_key = quote(key, safe="")
+        items = self._api_get(f"/v1/vaults/{self.vault_id}/items?filter=title%20eq%20%22{encoded_key}%22")
         if not items:
             return None
         item_list = items if isinstance(items, list) else items.get("items", [])
@@ -370,9 +373,12 @@ def set(self, key: str, value: str) -> bool:
         return self._api_post(f"/v1/vaults/{self.vault_id}/items", payload)
 
     def delete(self, key: str) -> bool:
+        from urllib.parse import quote
+
         import requests
 
-        items = self._api_get(f"/v1/vaults/{self.vault_id}/items?filter=title%20eq%20%22{key}%22")
+        encoded_key = quote(key, safe="")
+        items = self._api_get(f"/v1/vaults/{self.vault_id}/items?filter=title%20eq%20%22{encoded_key}%22")
         if not items:
             return False
         item_list = items if isinstance(items, list) else items.get("items", [])
diff --git a/tests/test_auth.py b/tests/test_auth.py
new file mode 100644
index 0000000..432f74d
--- /dev/null
+++ b/tests/test_auth.py
@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+import json
+
+from envault.auth import OAuth2Auth
+
+
+def test_oauth2_introspection_url_encodes_reserved_token_characters(monkeypatch):
+    captured: dict[str, object] = {}
+
+    class _Response:
+        status = 200
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, exc_type, exc_value, traceback):
+            return False
+
+        def read(self):
+            return json.dumps({"active": True, "sub": "synthetic-user"}).encode()
+
+    def fake_urlopen(request, timeout):
+        captured["request"] = request
+        captured["timeout"] = timeout
+        return _Response()
+
+    monkeypatch.setattr("envault.auth.urlopen", fake_urlopen)
+
+    result = OAuth2Auth(provider_url="https://identity.example", strategy="introspect").check(
+        {"Authorization": "Bearer token+with&reserved=value"}
+    )
+
+    assert result.success
+    request = captured["request"]
+    assert request.data == b"token=token%2Bwith%26reserved%3Dvalue"
+    assert captured["timeout"] == 10
diff --git a/tests/test_backup_manifest.py b/tests/test_backup_manifest.py
new file mode 100644
index 0000000..24302c9
--- /dev/null
+++ b/tests/test_backup_manifest.py
@@ -0,0 +1,80 @@
+"""Tests for backup manifest loading resilience."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from envault.backup import BACKUP_MANIFEST, _load_manifest
+
+
+def _write_manifest(backup_dir: Path, data: list[dict]) -> None:
+    """Helper to write raw manifest JSON."""
+    manifest_path = backup_dir / BACKUP_MANIFEST
+    manifest_path.write_text(json.dumps(data), encoding="utf-8")
+
+
+def test_load_manifest_skips_corrupt_entries(tmp_path: Path) -> None:
+    """A single corrupt entry must not discard valid entries.
+
+    Regression: previously a KeyError on any entry caused the entire
+    manifest to be silently discarded, losing all valid backups.
+    """
+    valid_entry = {
+        "name": "good-backup",
+        "source_file": ".env",
+        "backup_path": str(tmp_path / "good-backup"),
+        "timestamp": "2026-08-10T00:00:00+00:00",
+        "encrypted": False,
+    }
+    corrupt_entry = {"name": "missing-fields"}  # missing source_file, backup_path, timestamp
+
+    _write_manifest(tmp_path, [valid_entry, corrupt_entry])
+
+    entries = _load_manifest(tmp_path)
+
+    assert len(entries) == 1
+    assert entries[0].name == "good-backup"
+    assert entries[0].source_file == ".env"
+
+
+def test_load_manifest_all_corrupt_returns_empty(tmp_path: Path) -> None:
+    """When every entry is corrupt, return empty list without raising."""
+    _write_manifest(tmp_path, [{"bad": True}, {"also_bad": True}])
+
+    entries = _load_manifest(tmp_path)
+
+    assert entries == []
+
+
+def test_load_manifest_valid_json_but_not_list(tmp_path: Path) -> None:
+    """A manifest that is valid JSON but not a list returns empty."""
+    manifest_path = tmp_path / BACKUP_MANIFEST
+    manifest_path.write_text('{"not": "a list"}', encoding="utf-8")
+
+    entries = _load_manifest(tmp_path)
+
+    assert entries == []
+
+
+def test_load_manifest_preserves_order(tmp_path: Path) -> None:
+    """Valid entries are returned in their original order."""
+    entries_data = [
+        {
+            "name": f"backup-{i}",
+            "source_file": f".env.{i}",
+            "backup_path": str(tmp_path / f"backup-{i}"),
+            "timestamp": f"2026-08-10T00:0{i}:00+00:00",
+            "encrypted": False,
+        }
+        for i in range(5)
+    ]
+    # Insert a corrupt entry in the middle
+    entries_data.insert(2, {"corrupt": True})
+
+    _write_manifest(tmp_path, entries_data)
+
+    result = _load_manifest(tmp_path)
+
+    assert len(result) == 5
+    assert [e.name for e in result] == [f"backup-{i}" for i in range(5)]
diff --git a/tests/test_cli_edge_cases.py b/tests/test_cli_edge_cases.py
index dcd8c88..6c2452e 100644
--- a/tests/test_cli_edge_cases.py
+++ b/tests/test_cli_edge_cases.py
@@ -31,9 +31,7 @@ def _make_config(tmp_path, env_map):
     """Create minimal .envault.yml with list-formatted environments."""
     config = {
         "project": "test",
-        "environments": [
-            {"name": name, "env_file": path} for name, path in env_map.items()
-        ],
+        "environments": [{"name": name, "env_file": path} for name, path in env_map.items()],
     }
     config_path = tmp_path / ".envault.yml"
     with open(config_path, "w") as f:
@@ -171,9 +169,7 @@ def test_package_data_includes_py_typed(self):
         with open(pyproject, "rb") as f:
             data = tomllib.load(f)
         pkg_data = data.get("tool", {}).get("setuptools", {}).get("package-data", {})
-        assert "envault" in pkg_data, (
-            "Expected [tool.setuptools.package-data] section for 'envault'"
-        )
+        assert "envault" in pkg_data, "Expected [tool.setuptools.package-data] section for 'envault'"
         assert "py.typed" in pkg_data["envault"], (
             f"Expected 'py.typed' in package-data for envault, got {pkg_data['envault']}"
         )
@@ -184,8 +180,6 @@ def test_ruff_known_first_party(self):
         pyproject = Path(__file__).parent.parent / "pyproject.toml"
         with open(pyproject, "rb") as f:
             data = tomllib.load(f)
-        isort_cfg = (
-            data.get("tool", {}).get("ruff", {}).get("lint", {}).get("isort", {})
-        )
+        isort_cfg = data.get("tool", {}).get("ruff", {}).get("lint", {}).get("isort", {})
         kfp = isort_cfg.get("known-first-party", [])
         assert kfp == ["envault"], f"known-first-party should be ['envault'], got {kfp}"
diff --git a/tests/test_serve.py b/tests/test_serve.py
index d9d8317..452d487 100644
--- a/tests/test_serve.py
+++ b/tests/test_serve.py
@@ -675,6 +675,31 @@ def test_secrets_trailing_slash(self):
         assert handler._sent_status == 200
         assert "keys" in handler._sent_json
 
+    def test_auth_info_endpoint_accessible(self):
+        """GET /auth/info should return auth configuration without requiring auth."""
+        store = _FakeStore({})
+        handler = _make_handler(store, api_key="secret-token")
+        handler.path = "/auth/info"
+        handler.do_GET()
+
+        assert handler._sent_status == 200
+        data = handler._sent_json
+        assert "auth_mode" in data
+        assert data["auth_mode"] == "bearer"
+        assert data["requires_auth"] is True
+
+    def test_auth_info_no_auth_configured(self):
+        """GET /auth/info should show 'any' mode when no api_key is set."""
+        store = _FakeStore({})
+        handler = _make_handler(store, api_key=None)
+        handler.path = "/auth/info"
+        handler.do_GET()
+
+        assert handler._sent_status == 200
+        data = handler._sent_json
+        assert data["auth_mode"] == "any"
+        assert data["requires_auth"] is False
+
 
 # ── Tests: API Authentication ──────────────────────────────────────────────────
 
diff --git a/tests/test_stores_integration.py b/tests/test_stores_integration.py
index e18c000..e03b9dc 100644
--- a/tests/test_stores_integration.py
+++ b/tests/test_stores_integration.py
@@ -465,6 +465,58 @@ def test_list_keys_with_prefix(self):
             keys = store.list_keys(prefix="DB_")
             assert keys == ["DB_HOST", "DB_PORT"]
 
+    def test_get_url_encodes_special_characters_in_key(self):
+        """Keys with special chars (&, =, #, spaces, quotes) must be URL-encoded in the filter."""
+        from urllib.parse import quote
+
+        import responses
+
+        from envault.stores import OnePasswordStore
+
+        store = OnePasswordStore(token="fake", vault_id="v1")
+        base_url = "http://localhost:8080/v1/vaults/v1/items"
+        # Key with characters that break unencoded URLs
+        key = 'MY&KEY=WITH#SPECIAL "CHARS"'
+        encoded_key = quote(key, safe="")
+        filter_url = f"{base_url}?filter=title%20eq%20%22{encoded_key}%22"
+
+        with responses.RequestsMock() as rsps:
+            items = [
+                {
+                    "title": key,
+                    "fields": [{"purpose": "PASSWORD", "value": "secret_val"}],
+                }
+            ]
+            rsps.get(filter_url, json=items)
+            result = store.get(key)
+            assert result == "secret_val"
+            # Verify the request was made with the properly encoded URL
+            assert len(rsps.calls) == 1
+            assert encoded_key in rsps.calls[0].request.url
+
+    def test_delete_url_encodes_special_characters_in_key(self):
+        """delete() must also URL-encode keys with special characters."""
+        from urllib.parse import quote
+
+        import responses
+
+        from envault.stores import OnePasswordStore
+
+        store = OnePasswordStore(token="fake", vault_id="v1")
+        base_url = "http://localhost:8080/v1/vaults/v1/items"
+        key = "KEY/WITH/SLASHES&AMP"
+        encoded_key = quote(key, safe="")
+        filter_url = f"{base_url}?filter=title%20eq%20%22{encoded_key}%22"
+        item_id = "item-del-special"
+
+        with responses.RequestsMock() as rsps:
+            rsps.get(filter_url, json=[{"id": item_id, "title": key}])
+            rsps.delete(f"{base_url}/{item_id}", status=204)
+            result = store.delete(key)
+            assert result is True
+            assert len(rsps.calls) == 2
+            assert encoded_key in rsps.calls[0].request.url
+
 
 # ── Store factory deeper tests ──────────────────────────────────────────────