This is an initial attempt to implement evals for all (or most) of our
foundational examples. Before we release, we want to make sure all of them work
and reply properly. Until now this has been done manually, hopefully this will
be useful to speed up our release process.
### Summary
This PR improves the MCP (Model Context Protocol) client's SSE (Server-Sent Events) server connection handling by replacing the generic string parameter with a proper `SseServerParameters` class.
### Changes
- **Breaking Change**: Changed `server_params` type from `Union[StdioServerParameters, str]` to `Union[StdioServerParameters, SseServerParameters]`
- Added import for `SseServerParameters` from `mcp.client.session_group`
- Updated SSE client connection to use structured parameters instead of a simple URL string
- Fixed error message to correctly reflect the expected parameter types
- Improved logging by changing info-level log to debug-level for consistency
### Details
#### Before
The SSE client connection only accepted a URL string:
```python
async with self._client(self._server_params) as (read, write):
```
#### After
Now properly unpacks SSE server parameters:
```python
async with self._client(
url=self._server_params.url,
headers=self._server_params.headers,
timeout=self._server_params.timeout,
sse_read_timeout=self._server_params.sse_read_timeout
) as (read, write):
```
### Benefits
- **Type Safety**: Stronger type checking with dedicated `SseServerParameters` class
- **Extended Configuration**: Support for custom headers (authentication), timeouts, and SSE-specific settings
- **Better Error Messages**: Clear type error messages when incorrect parameters are provided
- **Improved Debugging**: Debug logging of SSE server parameters for troubleshooting
### Migration Guide
Users need to update their SSE server initialization:
```python
# Before
client = MCPClient("https://example.com/sse")
# After
from mcp.client.session_group import SseServerParameters
client = MCPClient(SseServerParameters(
url="https://example.com/sse",
headers={"Authorization": "Bearer token"},
timeout=30,
sse_read_timeout=60
))
```
### Testing
- [ ] Tested with StdioServerParameters (unchanged behavior)
- [ ] Tested with SseServerParameters with various configurations
- [ ] Verified error handling for invalid parameter types
---
This is a necessary change to support production-ready SSE connections with proper authentication and timeout handling.
