Add MCPEnv to envs.experimental

[willccbb]

Description

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Test improvement

Testing

• All existing tests pass when running uv run pytest locally.
• New tests have been added to cover the changes

Checklist

• My code follows the style guidelines of this project as outlined in AGENTS.md
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Additional Notes

---

Note

Add new mcp-search-env built on verifiers.envs.experimental.MCPEnv, remove old in-repo mcp_env, and update deps/tests accordingly.

• Environments:
  • Add environments/mcp_search_env/ with mcp_search_env.py and README; uses verifiers.envs.experimental.MCPEnv and requires EXA_API_KEY.
  • Remove legacy in-repo MCP implementation (environments/mcp_env/ incl. mcp_env.py, mcp_server_connection.py, mcp_tool_wrapper.py, models.py) and associated output artifacts under outputs/evals/.
• Dependencies:
  • Update root pyproject.toml deps (add math-verify, prime-sandboxes, pydantic, etc.) and include mcp in envs optional extras; add environments/mcp_search_env/pyproject.toml with verifiers>=0.1.8.post2 and mcp>=1.0.0.
• Tests:
  • Adjust tests/test_envs.py to skip mcp_search_env (requires EXA_API_KEY) and remove skip for mcp_env.
• Repo housekeeping:
  • Tweak .gitignore to ignore root __pycache__/.

^{Written by Cursor Bugbot for commit 6d7bc97. This will update automatically on new commits. Configure here.}

[cursor]

Unused python-dotenv dependency breaks .env file loading

The old mcp_env.py called load_dotenv() to automatically load environment variables from .env files, but the new mcp_search_env.py does not import or use python-dotenv despite listing it as a dependency. Users who previously relied on .env files for EXA_API_KEY will now receive a RuntimeError even with a valid .env file present. Either the dependency should be removed if .env loading is not intended, or load_dotenv() should be called before checking os.environ.get("EXA_API_KEY").

Additional Locations (1)

• environments/mcp_search_env/pyproject.toml#L6-L7