fix(bedrock): raise_for_status in WrappedBotoClient so gateway errors surface

[vldcmp-uipath]

Problem

WrappedBotoClient (the httpx-backed Bedrock shim that replaces boto3 when talking to the LLM Gateway) read responses with .json() / iter_bytes() without checking the HTTP status. On a non-2xx gateway response — e.g. a 403 License not available — the error body was parsed as if it were a normal Converse result and handed to langchain_aws, which then raised a misleading:

ValueError: No 'output' key found in the response from the Bedrock Converse API.
This usually happens due to misconfiguration of endpoint or region ...

The real status code (403) and the gateway's detail ("…you need additional 'AGU'") were lost — so a licensing error surfaced as a confusing "check your endpoint/region" message.

Fix

Call response.raise_for_status() before reading the body in converse, invoke_model, and the streaming generator (_stream_generator, used by converse_stream / invoke_model_with_response_stream). The UiPath httpx client's patched raise_for_status then raises the typed UiPathAPIError subclass (e.g. UiPathPermissionDeniedError, carrying .status_code and .body).

For streaming responses the error body is read first (if response.is_error: response.read()), since the gateway returns a non-streamed JSON error body and UiPathAPIError.from_response parses response.json() to populate detail. Verified on httpx 0.28.1 that is_error / status_code are available from the response headers inside the stream() context before the body is read, and that the success path still streams via iter_bytes().

Verification

Confirmed end-to-end against a real gateway 403: the Bedrock Converse path now produces UiPathPermissionDeniedError(status_code=403, body={... "detail": "License not available ... 'AGU'" ...}) instead of the opaque ValueError.

Tests

New tests/langchain/clients/bedrock/test_wrapped_boto_client.py:

• converse / invoke_model raise on a 403 (and converse returns the body on 200)
• converse_stream / invoke_model_with_response_stream raise on a 403 when consumed

🤖 Generated with Claude Code