mcp: outdated calls AI models write
3 corrections for mcp 2.3.0 (PyPI): code that claude-sonnet-5-5, gemini-3.8-flash and gpt-6.1-sol wrote in our sandbox runs for 1.26.0 and earlier, which fails on 2.3.0. Each one is verified on both versions.
- Corrections
- 3
- Fails on
- 2.3.0
- Works on
- 1.26.0
- Released
- 2026-10-02
| Changed API | Change | Models wrote | Correct | Error | Seen in | Worked |
|---|---|---|---|---|---|---|
| mcp.shared.session | behaviour changed | shared_session.anyio.create_memory_object_stream(1) | anyio.create_memory_object_stream(1) | ImportError | gpt-6.1-sol | 1/1 |
| scopes | renamed | scopes=SCOPE, | scope=SCOPE, | TypeError | claude-sonnet-5-5 | 2/2 |
| FastMCP | changed | from mcp.server.fastmcp import Context, FastMCP | from mcp.server.mcpserver import Context, MCPServer | ModuleNotFoundError | claude-sonnet-5-5, gemini-3.8-flash, gpt-6.1-sol | 10/10 |
Wide table: scroll it sideways to see every column.
| Model | Answers run | Outdated code found | Share |
|---|---|---|---|
| claude-sonnet-5-5 | 12 | 10 | 83 % |
| gpt-6.1-sol | 12 | 8 | 67 % |
| gemini-3.8-flash | 12 | 5 | 42 % |
For agents
- This page as JSON:
https://formachines.ai/errata/pypi/mcp/index.json - Whole database in plain text:
/errata/llms-full.txt - Install the skill:
npx skills add formachines-ai/skills@model-errata(source on GitHub) - Confirm, dispute or add a correction: feedback form and API
- Apply a correction on your own only when its
proof.auto_applyis true (Automatic application is allowed only when proof.equivalent is true and proof.applicability.status is applies; otherwise show the correction to the user as a lead and do not apply it on your own.)