OpenCode

OpenCode does not read claude_desktop_config.json. Put the server in the project opencode.json or opencode.jsonc, or globally in ~/.config/opencode/opencode.json (Windows: %USERPROFILE%\.config\opencode\opencode.json).

Differences from Claude Desktop:

	Claude Desktop	OpenCode
Key	mcpServers	mcp
type	omitted	local (required)
command	binary, flags in args	one array: binary, flags, paths
timeout	client default	default 5s is too short for tools/list. Set 30000.

Quit and restart OpenCode after saving.

Windows:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "filesystem-ultra": {
      "type": "local",
      "command": [
        "C:\\path\\to\\filesystem-ultra-v4.exe",
        "--profile", "strict",
        "--compact-mode",
        "--cache-size", "200MB",
        "--parallel-ops", "8",
        "--log-level", "error",
        "--log-dir", "C:\\logs\\mcp-filesystem",
        "--roots-mode", "union",
        "C:\\your\\project\\"
      ],
      "enabled": true,
      "timeout": 30000
    }
  }
}

Linux: same shape, with /path/to/filesystem-ultra and a Linux --log-dir.

--roots-mode

Default is replace. OpenCode sends the workspace as MCP Roots and replaces the CLI allowlist with that one folder. A config with many paths will look correct on disk, but list_allowed_directories will only show the workspace.

Mode	Effect
replace (default)	Client Roots replace the CLI list. OpenCode: only the workspace.
union	CLI paths plus the workspace. Use this when the allowlist must survive.
ignore	CLI list only. Client Roots are ignored.

Copy examples/harness/ instead of guessing flags. One MCP instance per workspace. One role uses one disk family. Do not mix native Read/Edit with this server. Codex *** Begin Patch is not apply_patch.