Show HN: Cross-platform computer use MCP server built in Rust

Cross-platform desktop automation for MCP clients on macOS, Windows, and Linux. The server exposes 64 stable v7 tools for screenshots, input, applications, windows, accessibility, scripting, files, processes, registry operations, and virtual desktops.

Version 7.1 keeps the v7 tool API intact while serving both MCP 2026-07-28 and legacy 2025 clients with the exact @modelcontextprotocol/* 2.0.0 SDK packages. Node.js 20 or newer is required. Clients that do not support the modern stateless protocol continue to receive the existing v7 behavior.

• MCP client roots constrain filesystem tools and filesystem resources.
• Resources support subscriptions and notifications/resources/updated .
• Successful filesystem operations return readable MCP resource links.
• Sanitized MCP logging reports lifecycle and tool outcomes without arguments, results, secrets, clipboard contents, or screenshots.
• Approval elicitation identifies the exact tool, target, operation, path, destination, process, registry value, or bounded script involved.
• Tools have human-readable discovery titles.
• Prompt application arguments support MCP completion.
• Dynamic v7 profile changes emit notifications/tools/list_changed through the SDK.
• Stateless MCP 2026-07-28 requests use server/discover , per-request identity/capability envelopes, cache hints, in-band multi-round-trip input, andsubscriptions/listen .
• The official io.modelcontextprotocol/tasks extension is implemented for selected long-running read-only tools, including polling, cancellation, TTLs, routing headers, and caller isolation.
• A fetch-shaped stateless HTTP handler and a loopback-only HTTP runner are included alongside stdio.
• The former v8 preview surface, packages, contracts, migration commands, and remote supervisor have been removed.

Requires Node.js 20 or newer.

npx -y @zavora-ai/computer-use-mcp@7.1.0

Example MCP configuration:

{
  "mcpServers": {
    "computer-use": {
      "command": "npx",
      "args": ["-y", "@zavora-ai/computer-use-mcp@7.1.0"]
    }
  }
}

For local Streamable HTTP, run:

npx -y --package @zavora-ai/computer-use-mcp@7.1.0 computer-use-mcp-http

The bundled runner refuses non-loopback binds and validates Host and Origin. Remote deployments should embed the fetch-shaped handler behind verified OAuth middleware.

The v7.1 npm tarball contains the matching native binary for:

• macOS arm64 and x64
• Windows arm64 and x64
• Linux arm64 and x64

On macOS, grant the terminal or MCP host Screen Recording and Accessibility permission. Automation permission may also be requested when run_script controls another application.

On Windows, the server uses UI Automation, SendInput, PowerShell, and native window APIs. Run at the same integrity level as the applications being automated.

On Linux, screenshot and input support depend on the active X11/Wayland environment and installed backend. Run doctor to obtain machine-specific remediation.

flowchart LR
  Client["MCP 2026 or legacy client"] <-->|"stdio or Streamable HTTP"| Entry["SDK v2 serving entry"]
  Entry --> Server["McpServer 7.1 per request/connection"]
  Server --> Registry["64-tool registry"]
  Server --> Protocol["MRTR roots/elicitation, Tasks, subscriptions"]
  Server --> Resources["Prompts and resources"]
  Registry --> Session["Policy, targeting, lock, cancellation"]
  Session --> Native["Rust N-API backend"]
  Session --> Scripts["Bounded AppleScript, JXA, or PowerShell"]
  Native --> OS["macOS / Windows / Linux"]

Filesystem authority is the intersection of operator configuration and client-declared roots:

flowchart TD
  Request["Filesystem path"] --> Normalize["Normalize and resolve existing ancestors"]
  Normalize --> Env{"Inside COMPUTER_USE_FS_ROOTS?"}
  Env -->|"No"| Deny["fs_root_denied"]
  Env -->|"Yes or unset"| Roots{"Inside negotiated MCP client roots?"}
  Roots -->|"No"| Deny
  Roots -->|"Yes or unsupported"| Execute["Execute filesystem operation"]
  Execute --> Link["Return resource_link"]

See docs/ARCHITECTURE.md for protocol lifecycles and extension points. See docs/releases/v7.1.0.md for the complete release notes, compatibility boundary, verification evidence, and upgrade guidance.

Task status notifications are optional in the extension and are not advertised; clients poll at pollIntervalMs. Sampling, MCP Apps, and authentication extensions are not advertised: this server does not need model delegation or an embedded UI, and remote authentication must be supplied by the embedding host rather than simulated. Legacy roots, logging, and elicitation remain available during the protocol deprecation window.

Tasks require an extension-aware host. The core @modelcontextprotocol/client 2.0.0 client negotiates MCP 2026-07-28 but intentionally rejects the extension-only resultType: "task"; do not advertise io.modelcontextprotocol/tasks from that client unless the host adds a Tasks extension codec. Clients that omit the extension capability always receive the ordinary synchronous CallToolResult shape.

• diagnose-desktop — inspect permissions and configuration.
• fill-form — accessibility-first form filling.
• script-first — prefer scripting over physical input.
• safe-desktop-task — policy-aware desktop automation.

The full profile exposes 64 tools:

• Observation: screenshot ,zoom ,cursor_position ,get_display_size ,list_displays ,get_frontmost_app ,list_windows ,list_running_apps ,get_window ,get_cursor_window ,snapshot .
• Pointer and keyboard: left_click ,right_click ,middle_click ,double_click ,triple_click ,mouse_move ,left_click_drag ,left_mouse_down ,left_mouse_up ,scroll ,type ,key ,hold_key ,multi_select ,multi_edit .
• Accessibility: get_ui_tree ,get_focused_element ,find_element ,click_element ,set_value ,press_button ,select_menu_item ,fill_form ,list_menu_bar .
• Applications and windows: open_application ,activate_app ,activate_window ,resize_window ,hide_app ,unhide_app .
• Scripting and advice: run_script ,get_app_dictionary ,get_tool_guide ,get_app_capabilities ,get_tool_metadata .
• Clipboard and virtual pointer: read_clipboard ,write_clipboard ,agent_pointer ,openai_computer .
• System operations: filesystem ,process_kill ,registry ,notification ,scrape .
• Virtual desktops: list_spaces ,get_active_space ,create_agent_space ,move_window_to_space ,remove_window_from_space ,destroy_space .
• Administration: doctor ,policy_status ,wait .

Use MCP tools/list for the authoritative schemas and annotations.

Prefer the least disruptive mechanism:

1. Direct filesystem or system tools.
2. AppleScript, JXA, or PowerShell through run_script .
3. Accessibility/UI Automation tools.
4. Coordinate mouse and keyboard input.

Use get_tool_guide and get_app_capabilities before unfamiliar workflows. Supply target_app or target_window_id for physical input whenever possible.

COMPUTER_USE_PROFILE defines the maximum authority available to the process:

Embedded hosts may set a narrower active v7 profile through onRegistry. The active profile can never expand beyond the maximum profile, and changes generate MCP tool-list notifications.

import { createComputerUseServer } from '@zavora-ai/computer-use-mcp/server'

const server = createComputerUseServer({
  profile: 'full',
  activeProfile: 'core',
  onRegistry(registry) {
    // Host-controlled and automatically emits tools/list_changed after connect.
    registry.setActiveProfile('ax')
  },
})

The typed client is available from @zavora-ai/computer-use-mcp/client.

Stateless HTTP embedding:

import { createComputerUseHttpHandler } from '@zavora-ai/computer-use-mcp/server'

const handler = createComputerUseHttpHandler({ profile: 'full' })

// Pass only authInfo produced by a real verifier. The handler never trusts
// an Authorization header on its own.
const response = await handler.fetch(request, { authInfo })

This server can control the desktop and execute scripts with the permissions of its process. Treat the full profile as high privilege.

• Set COMPUTER_USE_FS_ROOTS , even when the client supplies roots.
• Require approval for destructive filesystem, process, registry, scripting, and external actions.
• Prefer stdio. The separate HTTP command opens only a loopback listener; remote serving requires an embedding host with authentication and authorization.
• Treat unauthenticated task IDs as bearer capabilities. Authenticated HTTP tasks are additionally bound to authInfo.clientId .
• Do not rely on MCP annotations as an authorization boundary.
• computer://screenshot/latest is cache-only.
• MCP logs intentionally exclude arguments, results, secrets, clipboard contents, scripts, and image bytes.

See SECURITY.md for the threat model and disclosure process.

npm ci
npm run build:ts
npm test

The v7.1.0 release gate additionally installs the packed universal tarball, imports every public entry point, tests both MCP protocol eras, and verifies all six native targets. The exact attested tarball is submitted with npm staged publishing for maintainer review and 2FA approval. See the v7.1.0 release record.

Native development requires the Rust toolchain and platform SDK:

npm run build:native

The release gate runs TypeScript compilation, Node tests, native builds on the supported target matrix, package-content verification, packed-install checks, SBOM generation, and build provenance attestation.

MIT © James Karanja Maina / Zavora Technologies Ltd.

The opt-in efficiency helpers provide lazy tool discovery, bounded accessibility observations, multimodal result projection, explicit retained-image reuse, and cancellable local waits. The OpenAI Responses example demonstrates these helpers with real image feedback and API usage reporting. Run npm run measure:efficiency for reproducible payload measurements. Existing MCP tool schemas and default results remain unchanged.