Agent Workspace MCP

🛡️ Agent Workspace MCP Server

A unified Model Context Protocol (MCP) server providing a highly secure, containerized workspace for Large Language Models (LLMs). It acts as an isolated "agentic playground" where agents can autonomously code, test, and debug without risking the host machine.

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✨ Features

• 🏗️ Full Project Lifecycle: Bootstrap projects with uv init, manage dependencies with uv add, and execute via uv run.
• 🐚 Secure Bash Access: Execute shell commands with mandatory timeouts and merged output streams.
• 🚀 Token-Optimized Output: Integrates RTK (Rust Token Killer) to automatically filter and compress run_bash outputs (like ls, git, and test runners), saving 60-90% of LLM context tokens.
• 📂 Robust Filesystem: Path-traversal protected operations for reading, writing, and searching the workspace.
• 🛡️ Multi-Layer Security: Non-root execution, dropped capabilities, resource limits, and a read-only root filesystem.
• ⚡ Precision Editing: Advanced search_and_replace with fuzzy whitespace matching, indentation preservation, dry-run support, and syntax validation for Python, JSON, JSONL, TOML, and YAML.
• 📊 Real-time Observability: Direct logging to MCP client UI and persistent rotating audit logs.

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🏗️ Architecture

flowchart TD

Client["MCP Client (Claude / Cursor)"] -- "stdio (JSON-RPC)" --> FastMCP["FastMCP Server"]

subgraph Sandbox ["Docker Sandbox Container (mcpuser)"] direction TB

FastMCP -. "Intercepts accidental prints" .-> StdioGuard["StdoutRedirector"] FastMCP -. "Application Logs" .-> Logger["Dual Logger (stderr & .mcp/server.log)"]

FastMCP -- "Tool Calls" --> SecurityGuard["Security & Path Validator"]

subgraph Toolset ["Tool Modules"] direction TB SecurityGuard --> FSTools["Filesystem (read, write, list, search)"] SecurityGuard --> EditTools["Editing (search_and_replace)"] SecurityGuard --> ExecTools["Execution (run_bash)"] end

EditTools -- "AST Verification" --> Validator["Syntax Validations (Python, JSON, JSONL, TOML, YAML)"] ExecTools -- "Process Group (Timeout=60s)" --> Shell["/bin/sh Subprocess"] Shell -- "Package Mgt & Checks" --> UV["uv Environment / Ruff"]

FSTools -- "Secure I/O" --> Workspace["/workspace Directory"] EditTools -- "Atomic Writes" --> Workspace Shell -- "Executes within" --> Workspace end

Workspace <--"Volume Mount"--> HostFS["User Host Filesystem"]

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📦 Quick Start

1. Pull or Build the Docker Image

# Pull from GHCR

docker pull ghcr.io/hrrodan/agent-workspace-mcp:latest

OR: Build locally with your host's UID/GID for optimal permissions

docker build --build-arg UID=$(id -u) --build-arg GID=$(id -g) -t agent-workspace-mcp .

2. Programmatic Usage (OpenAI Agents SDK)

Here is a quick boilerplate showing how to use the containerized workspace programmatically using the standard openai-agents SDK:

import asyncio

from agents import Agent, Runner from agents.mcp import MCPServerStdio

async def main():

1. Configure the MCP Server to run via Docker

server = MCPServerStdio( name="Sandboxed Workspace", params={ "command": "docker", "args": [ "run", "-i", "--rm", "--init",

"--network", "none", # Network Isolation (optional) - see below

"--memory=2g", "--cpus=2.0", "--pids-limit=256", "--cap-drop=ALL", "--security-opt=no-new-privileges:true", "--read-only", "--tmpfs", "/tmp:size=64m", "--tmpfs", "/home/mcpuser/.cache:size=512m", "--user", "1000:1000", # Replace with your host UID:GID "-v", "/path/to/your/projects:/workspace", "ghcr.io/hrrodan/agent-workspace-mcp:latest", ], }, client_session_timeout_seconds=60.0, )

2. Attach server to the Agent and load the skill instructions (optional)

with open("skills/agent-workspace-mcp/SKILL.md", "r") as f: skill_instructions = f.read()

agent = Agent( name="WorkspaceAgent", instructions=f"You are a coding agent with access to a secure workspace.\n\n{skill_instructions}", mcp_servers=[server], )

3. Execute a workflow

async with server: result = await Runner.run( agent, "Create a python script in the workspace to print the first 10 Fibonacci numbers, then run it." ) print(f"Agent's Final Output:\n{result.final_output}")

if name == "main": asyncio.run(main())

3. Use with MCP Clients (Claude / Cursor)

Add the following configuration to your claude_desktop_config.json or Cursor settings.

{

"mcpServers": { "agent-workspace-mcp": { "command": "docker", "args": [ "run", "-i", "--rm", "--init", // "--network", "none", // Network Isolation (optional) - see below "--memory=2g", "--cpus=2.0", "--pids-limit=256", "--cap-drop=ALL", "--security-opt=no-new-privileges:true", "--read-only", "--tmpfs", "/tmp:size=64m", "--tmpfs", "/home/mcpuser/.cache:size=512m", "--user", "1000:1000", "-v", "/path/to/your/projects:/workspace", "ghcr.io/hrrodan/agent-workspace-mcp:latest" ] } } }

[!IMPORTANT]

Linux Users: Replace 1000:1000 with your actual UID:GID (run id -u and id -g). Claude Desktop does not expand environment variables.

Signal Handling: The --init flag is essential for proper signal forwarding and zombie process reaping.

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🛠️ Tool Reference

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⚙️ Configuration

The server supports the following environment variables (passed via Docker --env):

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🛡️ Security & Architecture Model

This server employs a defense-in-depth strategy, explicitly separating strict security boundaries from developer experience and operational reliability features.

🔒 Core Security Features

These features are designed to protect the host system and enforce strict isolation boundaries.

• Kernel Hardening: All Linux capabilities are dropped (--cap-drop=ALL), neutralizing privilege escalation vectors.
• Immutable Server Code: The /app directory containing the server source and its virtual environment is owned by root and read-only for the mcpuser. This prevents the server from modifying itself or being tampered with via run_bash.
• Privilege Lockdown: Enforces no-new-privileges:true to prevent any process from gaining elevated rights.
• Immutable System Core: The container's root filesystem is mounted entirely read-only, providing a second layer of defense against OS-level tampering.
• Resource Quotas: Hard limitations on CPU, Memory, and PIDs mitigate denial-of-service (DoS) attempts like fork-bombs and host exhaustion.
• Strict Boundary Enforcement: A robust path validator comprehensively blocks all path traversal attacks outside the designated /workspace.
• Process & Resource Control: Mandatory command timeouts (default 60s) and strict process group isolation ensure runaway or malicious processes are killed.
• Memory-Overload Protection: Hard limits on file reads (1MB) and command outputs (50KB) prevent memory exhaustion.
• Information Leakage Prevention: Internal stack traces and system paths are suppressed and sanitized from tool outputs.

🛠️ Developer Experience & Convenience

Features focused on seamless integration, usability, and reducing friction during agentic workflows.

• Host-Aligned Non-Root Identity: Runs as mcpuser with UID/GID customizable at build time, eliminating tedious file permission conflicts on host volume mounts.
• Automatic Token Optimization: Shell commands executed via run_bash are transparently rewritten through RTK to provide ultra-compact, LLM-friendly output without altering underlying command behavior.
• Intelligent Search Exclusions: High-noise or sensitive directories (.git, .venv) are automatically ignored to keep context windows lean and relevant.
• Ephemeral Workspaces: Containers are strictly ephemeral (--rm), guaranteeing a clean, predictable slate for every new session without state leaking across connections.
• Standardized Discovery: Complies with the OCI Image Specification for standardized container ecosystem integration and transparent auditing.

⚙️ Reliability & Safety Mechanisms

Features ensuring the structural integrity of the workspace and providing observability.

• Pre-Write Syntax Validation: Both write_file and search_and_replace perform in-memory syntax validation for Python, JSON, JSONL, TOML, and YAML before persisting changes, preventing broken code states.
• Fail-Safe Writing: write_file blocks accidental overwrites of existing files by default and enforces a 5MB size guard to prevent workspace flooding.
• Atomic File Operations: Edits utilize temp-and-move logic to guarantee file integrity and prevent corruption, even during unexpected interruptions or crashes.
• Transparent Observability: All tool invocations and state changes are streamed in real-time to the MCP client UI for immediate operator oversight.

🌐 Network Isolation (Optional)

By default, the container has full network access via Docker's bridge network. For maximum isolation, you can completely disable the network stack using --network none:

docker run -i --rm --init \

--network none \ --memory=2g --cpus=2.0 --pids-limit=256 \ --cap-drop=ALL --security-opt=no-new-privileges:true \ --read-only \ --tmpfs /tmp:size=64m \ --tmpfs /home/mcpuser/.cache:size=512m \ --user 1000:1000 \ -v /path/to/your/projects:/workspace \ ghcr.io/hrrodan/agent-workspace-mcp:latest

This creates a fully air-gapped sandbox — only the loopback interface exists inside the container. All outbound connections (curl, DNS, uv add, etc.) will fail immediately, eliminating data exfiltration and lateral m