ctx setup opencode --write generates Unix-only MCP config on Windows

[omergk28]

ctx setup opencode --write generates Unix-only MCP config on Windows

Problem

ctx setup opencode --write generates an MCP server entry that uses sh -c and exec env:

"ctx": {
  "command": ["sh", "-c", "exec env CTX_DIR=\"$PWD/.context\" /path/to/ctx mcp serve"],
  "enabled": true,
  "type": "local"
}

This fails on Windows because sh, exec, and env don't exist. OpenCode interprets the failed subprocess as a connection close → MCP error -32000: Connection closed.

Steps to Reproduce

1. Install ctx on Windows (via go install or binary download)
2. Run ctx setup opencode --write from a workspace directory
3. Launch OpenCode — ctx MCP server fails immediately

Expected Behavior

ctx setup opencode --write should detect the OS and generate a platform-appropriate MCP command:

Windows (cmd):

"command": ["cmd", "/c", "set CTX_DIR=%CD%\\.context && ctx mcp serve"]

Windows (PowerShell):

"command": ["powershell", "-Command", "$env:CTX_DIR=\"$PWD\\.context\"; ctx mcp serve"]

Additional Context

Separately, the generated .opencode/plugins/ctx.ts calls ctx system bootstrap on session.created, which requires a .git/ directory. When the workspace root isn't a git repo, this emits:

git working tree required: ctx bootstrap: .git/ not found

The .nothrow().quiet() should suppress this, but it may contribute to confusion when debugging the MCP connection failure above.

Environment

• OS: Windows 11
• ctx: v0.8.1
• OpenCode: latest
• Shell: CMD (Command Prompt)