### 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.
