[mcp / Windows] npx MCP server fails to initialize (fileno)

## Observed symptom MCP npx server fails to initialize on Windows (fileno) [Bug] MCP npx server fails to initialize on Windows (fileno) Metadata Executive summary `MCP('npx -y @modelcontextprotocol/server-time')` raises **RuntimeError: fileno** on Windows during `__init__` (v4.7.11). Blocks MCP tool usage for Windows developers. Interactive triage `flowchart TD ` --- Terminal evidence `[FAIL] mcp_time_server 0.08s ` Same failure for `mcp_npx_inspect`. --- Environment matrix --- Architecture `flowchart LR ` |---------------|---- ## Literal error text ``` RuntimeError: MCP initialization failed: MCP initialization error: fileno ``` ## Version info v4.7.11 ## Environment Windows; npx MCP server ## Trigger / context Public GitHub report in MervinPraison/PraisonAI (FRESH_7D). ## Source evidence - https://github.com/MervinPraison/PraisonAI/issues/5598 (2026-10-02T08:34:10Z) — evidence_class: PRIMARY_ISSUE_REPORT — GitHub issue #5598 (OPEN) ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T09:33:42Z - scout_id: Cf319b794b6 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome. Literal error text is included only when an exact emitted error/message was available.