modelcontextprotocol / modelcontextprotocol/python-sdk
401 in Streamable HTTP should be handled gracefully
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 24.3k
- Forks
- 4k
- Avg merge
- 1d 1h
- Merged PRs (30d)
- 31
Description
Initial Checks
- I confirm that I'm using the latest version of MCP Python SDK
- I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue
Description
Currently, streamable_http will call response.raise_for_status() when handling POST requests. (ref).
This means that a 401 will bubble up and cause the entire program to crash.
While a 401 on server initialize could warrant an exception, we have a use case where a MCP server will return 401 for specific unauthorized operations, and allow others.
This should be handled gracefully, similar to how _handle_unexpected_content_type works, returning a JSONRPC message outlining an unauthorized exception was thrown.
This would let an agent or other client handle it instead of crashing the program.
Python & MCP Python SDK
Python 3.12 and MCP SDK v1.13.1
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in src/mcp/client/streamable_http.py at the POST handling around response.raise_for_status(), then compare it with _handle_unexpected_content_type. Trace how HTTP errors become client results; done means a 401 from an unauthorized operation produces a JSON-RPC unauthorized error message that the client can handle without crashing.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- api
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 74/100