Wrap non-JSON responses, read timeouts and connection errors in RouterError

CHANGELOG.md

@@ -4,6 +4,9 @@ All notable changes to this project are documented here. The format follows [Kee
 
 ## [Unreleased]
 
+### Fixed
+- `request_json` now raises `RouterError` (with the original exception chained) for non-JSON responses, read timeouts and connection errors, so `except RouterError:` fallbacks work as documented.
+
 ## [0.1.0] - 2026-09-23
 
 ### Added

src/model_router/_http.py

@@ -19,3 +19,9 @@ def request_json(url, api_key=None, body=None, timeout=60):
         raise RouterError(f"{url} -> HTTP {e.code}: {e.read().decode(errors='replace')[:500]}") from e
     except urllib.error.URLError as e:
         raise RouterError(f"{url} -> {e.reason}") from e
+    except TimeoutError as e:
+        raise RouterError(f"{url} -> timed out after {timeout}s") from e
+    except OSError as e:
+        raise RouterError(f"{url} -> {e}") from e
+    except (json.JSONDecodeError, UnicodeDecodeError) as e:
+        raise RouterError(f"{url} -> response was not valid JSON: {e}") from e

tests/test_http.py

@@ -53,6 +53,29 @@ def test_network_error_becomes_router_error(self):
                 request_json("https://x.test/a")
         self.assertIn("no route", str(ctx.exception))
 
+    def test_non_json_body_becomes_router_error(self):
+        resp = MagicMock()
+        resp.__enter__.return_value = io.BytesIO(b"<html>oops</html>")
+        with patch("urllib.request.urlopen", return_value=resp):
+            with self.assertRaises(RouterError) as ctx:
+                request_json("https://x.test/a")
+        self.assertIsInstance(ctx.exception.__cause__, json.JSONDecodeError)
+
+    def test_read_timeout_becomes_router_error(self):
+        resp = MagicMock()
+        resp.__enter__.return_value.read.side_effect = TimeoutError("The read operation timed out")
+        with patch("urllib.request.urlopen", return_value=resp):
+            with self.assertRaises(RouterError) as ctx:
+                request_json("https://x.test/a", timeout=5)
+        self.assertIn("timed out", str(ctx.exception))
+        self.assertIsInstance(ctx.exception.__cause__, TimeoutError)
+
+    def test_connection_reset_becomes_router_error(self):
+        with patch("urllib.request.urlopen", side_effect=ConnectionResetError("reset by peer")):
+            with self.assertRaises(RouterError) as ctx:
+                request_json("https://x.test/a")
+        self.assertIsInstance(ctx.exception.__cause__, ConnectionResetError)
+
 
 if __name__ == "__main__":
     unittest.main()