Umbriel MCP Server
by obscuritysrlio.github.ObscuritySRL/umbrielv1.14.0
See and drive a whole Windows machine from Bun — apps, input, screen, OCR, registry, OS — via MCP.
context tax
queued
security
queued
cold start
queued
freshness
Maintained55d ago
Install Umbriel MCP server
Install in Claude Code
claude mcp add umbriel -- npx -y umbrielInstall in Cursor
{
"mcpServers": {
"umbriel": {
"command": "npx",
"args": [
"-y",
"umbriel"
]
}
}
}Add to ~/.cursor/mcp.json (global) or .cursor/mcp.json (project).
Install in Claude Desktop
{
"mcpServers": {
"umbriel": {
"command": "npx",
"args": [
"-y",
"umbriel"
]
}
}
}Settings → Developer → Edit Config (claude_desktop_config.json), then restart.
Install in VS Code
{
"servers": {
"umbriel": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"umbriel"
]
}
}
}Add to .vscode/mcp.json in your workspace.
Install in Windsurf
{
"mcpServers": {
"umbriel": {
"command": "npx",
"args": [
"-y",
"umbriel"
]
}
}
}Add to ~/.codeium/windsurf/mcp_config.json.
Configuration
| Variable | Required | Secret | Description |
|---|---|---|---|
| UMBRIEL_PROFILE | — | — | Capability profile: 'readonly' (inspect/read only), 'safe' (read + input + window — default), or 'full' (also os + fs tools). |
| UMBRIEL_OS | — | — | Set to '1' to allow the 'os' tools (launch_app/run_program/open_path, kill_process, manage_process, control_service, set_env, registry_get/registry_list/registry_set) AND the 'fs' tools (read_file/write_file/list_dir/stat_path/make_dir/copy_file/move_file/delete_file) regardless of profile. |
| UMBRIEL_ALLOW | — | — | Comma-separated tool names or categories to additionally allow on top of the profile. |
| UMBRIEL_DENY | — | — | Comma-separated tool names or categories to deny, overriding the profile and UMBRIEL_ALLOW. |
| UMBRIEL_CURSOR | — | — | Set to 'never' to forbid the real-cursor fallback entirely (strictly cursor-free). By default clicks/drags are cursor-free but fall back to the real hardware cursor when no cursor-free path exists. |
| UMBRIEL_FS_ROOT | — | — | Sandbox root directory that the fs-category file tools (read_file/write_file/list_dir/stat_path/make_dir/copy_file/move_file/delete_file) are confined to when fs tools are enabled; open_path's path argument is honored too. |
| UMBRIEL_TRACE | — | — | File path to journal every mutating tool call as JSON Lines (tool, category, masked args, ok, observation); secret-bearing args and values are redacted. Unset = no trace. |
| UMBRIEL_FFI_TRACE | — | — | File path to a flush-before-call diagnostic journal of every COM vcall (slot, this-pointer, arg count). Each line is written and flushed to the OS BEFORE the native call, so after an uncatchable crash the last line names the faulting call. Has per-call overhead; unset = off. For debugging native faults only. |
| UMBRIEL_AUDIT | — | — | Controls the default-on stderr audit of mutating tool calls. 'off' is the explicit opt-out (reported at startup); 'verbose' also audits reads. |
| UMBRIEL_REDACT | — | — | Credential masking (default on). 'off' opts out; a regex value overrides the built-in secret shapes masked in clipboard/env/registry reads and the trace journal. |
Freshness
Maintained — last maintenance signal 55d ago. The newest of the signals below sets the band.
Last commit (default branch)
2026-08-15 · 55d ago · GitHub
Latest release
no data · GitHub
Package published
no data · npm/PyPI
Registry entry updated
2026-06-27 · 4mo ago · official registry · v1.14.0
FAQ
›How do I install the Umbriel MCP server in Claude Code?
Run: claude mcp add umbriel -- npx -y umbriel. For Cursor, VS Code, Claude Desktop and Windsurf, use the install tabs above.
›Does Umbriel require an API key?
No required environment variables are declared in its published metadata.
›Can I use Umbriel as a remote (hosted) MCP server?
No hosted endpoint is published; it runs locally over stdio.
›Is Umbriel in the official MCP registry?
Yes, as io.github.ObscuritySRL/umbriel.