[BUG] Windows: Atlassian Remote MCP Server fails to connect

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.51 (Claude Code)
• Operating System: Windows 11
• Terminal: PowerShell

Bug Description

Atlassian Remote MCP Server fails to connect when launched by Claude Code on Windows, showing immediate child process termination (~600ms). The same npx -y mcp-remote command works perfectly when run manually, suggesting a Claude Code child process management issue.

Steps to Reproduce

1. Create .mcp.json with Atlassian remote server configuration:

{
  "mcpServers": {
    "atlassian": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.atlassian.com/v1/sse"]
    }
  }
}

1. Launch Claude Code in directory containing .mcp.json
2. Run /mcp command to check MCP server status
3. Observe "Status: ✘ failed"
4. Multiple restarts show consistent failure

Expected Behavior

MCP server should connect successfully and show available Atlassian tools via /tools command, similar to manual execution which shows "Connected to remote server using SSEClientTransport" and "Proxy established successfully".

Actual Behavior

• /mcp shows Status: ✘ failed
• /status shows ⚠ atlassian
• Child process terminates after ~601ms, then ~68ms on retry
• No MCP protocol communication occurs
• /tools shows only built-in Claude Code tools, no Atlassian tools

Additional Context

Manual Command Works:

• npx -y mcp-remote https://mcp.atlassian.com/v1/sse
• Successfully connects with fallback from HTTP 404 to SSE-only transport.

Environment Details:

• Node.js: v22.17.0
• NPM: 10.9.2
• Network connectivity confirmed (manual connection works)

Log Evidence:

Claude Code MCP logs show "MCP error -32000: Connection closed" after 601ms, followed by a retry that fails after 68ms. The child process appears to start but the MCP connection fails during protocol handshake. This suggests either a communication protocol issue or the child process is closing the connection unexpectedly during MCP initialization.

Key Distinction:

This is immediate termination (not infinite hang like #1663) and Windows-specific (not macOS keychain issue like #3421).