mcp_io_process

Policy-gated, sandboxed OS process / shell execution adapter for mcp_io.

It registers a process-execution "device" with an IoRuntime, so the existing io.* tool surface drives sandboxed command execution — no new tool verbs. Desktop / VM only (uses dart:io).

Security model

Two layers cooperate:

1. Authorization — mcp_io PolicyEngine. Deny-by-default. Rules opt specific actor roles into the process actions. process.spawn is forced through the io.plan_execute → io.commit_execute two-phase flow.
2. Execution sandbox — ProcessSandboxConfig. Even when authorized, a command is constrained by:
   • executable allowlist (empty = nothing runs),
   • working-directory allowlist (a cwd must sit within an allowed root),
   • environment allowlist (the full parent environment is never inherited),
   • per-stream output cap and a wall-clock timeout,
   • an off-by-default shell-evaluation gate (argv-only by default).

Actions

Usage

import 'package:mcp_io/mcp_io.dart';
import 'package:mcp_io_process/mcp_io_process.dart';

final runtime = IoRuntime(
  policyPort: InMemoryIoPolicyPort(
    initialRules: ProcessPolicy.recommendedRules(roles: const ['operator']),
  ),
  auditPort: myAuditPort,
);
await runtime.initialize();

final adapter = ProcessAdapter(
  config: const ProcessSandboxConfig(
    executableAllowlist: ['git', 'flutter'],
    allowedRoots: ['/work/project'],
  ),
);
await runtime.registry.registerAdapter(adapter.manifest, adapter);
await runtime.registry.discover();

// Now reachable through io.execute / io.plan_execute / io.commit_execute.

The embedding host (AppPlayer / Studio) opts in by registering the adapter; web and headless hosts simply do not.