fix: use API detail message in BundleNotFoundError instead of raw URL

src/musher/_http.py

@@ -89,7 +89,12 @@ def _raise_for_status(response: httpx.Response) -> None:
         raise AuthenticationError("Invalid or missing API token")
 
     if status == 404:  # noqa: PLR2004
-        raise BundleNotFoundError(str(response.url))
+        try:
+            body_404: dict[str, object] = response.json()  # pyright: ignore[reportAny]
+            detail_404 = str(body_404.get("detail", ""))
+        except (ValueError, KeyError):
+            detail_404 = ""
+        raise BundleNotFoundError(detail_404 or str(response.url))
 
     if status == 429:  # noqa: PLR2004
         retry_after_header: str | None = response.headers.get("Retry-After")  # pyright: ignore[reportAny]

tests/test_http.py

@@ -64,6 +64,22 @@ async def test_404_raises_bundle_not_found(self, transport: HTTPTransport):
         with pytest.raises(BundleNotFoundError):
             await transport.get("/v1/test")
 
+    @respx.mock
+    async def test_404_with_json_body_uses_detail(self, transport: HTTPTransport):
+        respx.get("https://api.test.dev/v1/test").mock(
+            return_value=httpx.Response(
+                404,
+                json={
+                    "type": "https://api.platform.musher.dev/errors/not-found",
+                    "title": "Resource Not Found",
+                    "status": 404,
+                    "detail": "Bundle version with identifier '1.0.0' not found",
+                },
+            )
+        )
+        with pytest.raises(BundleNotFoundError, match="Bundle version with identifier"):
+            await transport.get("/v1/test")
+
     @respx.mock
     async def test_429_raises_rate_limit_with_retry_after(self, transport: HTTPTransport):
         respx.get("https://api.test.dev/v1/test").mock(