René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"raise without from discards exception chain in 12 remaining sites","articleBody":"### Initial Checks\n\n- [x] I confirm that I'm using the latest version of MCP Python SDK\n- [x] I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue\n\n### Description\n\nFollow-up to #2541 (fixed in #2542). The same pattern exists in 12 additional sites across 7 files. Each catches an exception and re-raises a new one without `from`, discarding the original traceback and `__cause__`.\n\n**Sites:**\n\n| File | Line | Caught | Raised |\n|------|------|--------|--------|\n| `client/session.py` | 346 | `ValidationError` | `RuntimeError` |\n| `client/session.py` | 348 | `SchemaError` | `RuntimeError` |\n| `client/auth/utils.py` | 246 | `ValidationError` | `OAuthRegistrationError` |\n| `client/auth/utils.py` | 339 | `ValidationError` | `OAuthTokenError` |\n| `server/auth/middleware/client_auth.py` | 83 | `ValueError`/`UnicodeDecodeError`/`binascii.Error` | `AuthenticationError` |\n| `server/mcpserver/resources/types.py` | 75 | `Exception` | `ValueError` |\n| `server/mcpserver/resources/types.py` | 151 | `Exception` | `ValueError` |\n| `server/mcpserver/resources/types.py` | 196 | `Exception` | `ValueError` |\n| `server/mcpserver/resources/types.py` | 205 | `Exception` | `ValueError` |\n| `server/mcpserver/resources/resource_manager.py` | 96 | `Exception` | `ValueError` |\n| `server/mcpserver/resources/templates.py` | 133 | `Exception` | `ValueError` |\n| `server/mcpserver/prompts/base.py` | 185, 189 | `Exception` | `ValueError` |\n\n### Impact\n\nSame as #2541: without `from`, Python shows \"During handling of the above exception, another exception occurred\" instead of \"The above exception was the direct cause of the following exception.\" Callers cannot inspect `__cause__` to determine the root cause programmatically.\n\nThe codebase already uses `from` correctly in `server.py:451`, `server.py:459`, `server.py:1112`, `func_metadata.py:216,265`, and `tools/base.py:119`. These 12 sites are the remaining inconsistencies.","author":{"url":"https://github.com/blackwell-systems","@type":"Person","name":"blackwell-systems"},"datePublished":"2026-05-08T19:50:46.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/2564/python-sdk/issues/2564"}