Pepper MCP Server for iOS Simulator Interaction and Debugging
Pepper is an MCP server that enables AI agents to directly interact with and debug iOS simulator applications in real time. It works by injecting a dynamic library (dylib) into the iOS simulator app process using the DYLD_INSERT_LIBRARIES environment variable.
Core Functionality
Under the hood, Pepper runs a WebSocket server inside the iOS app process. The MCP server connects to this WebSocket bridge and provides structured access to the application's internal state, allowing agents to understand what's happening rather than relying on screenshots or previews.
Specific Capabilities
- Read the screen content
- Tap buttons and scroll
- Inspect live Swift variables at runtime
- Check network traffic
- Toggle feature flags
- Run accessibility audits
- Access the full view hierarchy
- Examine runtime state and app internals
Practical Applications
The creator uses Pepper for multiple development tasks:
- PR validation
- Bug reproduction
- Building full features end-to-end
- Verifying agent-generated code in parallel development workflows
The repository itself is built by agents running in parallel, using Pepper to verify their own work as they go.
📖 Read the full source: r/ClaudeAI
👀 See Also
Off Grid: Utilizing Phone Hardware for Offline AI Applications
Off Grid is an open-source app that uses your phone's hardware for offline AI tasks like text generation and voice transcription.
PocketBot: iOS app uses Claude to generate deterministic JavaScript automations from natural language
PocketBot is an iOS mobile automation app that uses Claude via AWS Bedrock to convert plain-language requests into self-contained JavaScript scripts. The LLM writes the code once, then the deterministic scripts run on schedule in a sandboxed runtime without AI involvement.
ClaudeAI Brainstorming Mode Gets Visual Companion for Mockups and UI Approval
A user discovers a new 'Visual companion' feature in ClaudeAI brainstorming mode that serves mockups on a local web server, enabling back-and-forth UI tweaks before building.
Claude Code Dynamic Workflows: Parallel Subagents & UltraCode Mode
Claude Code introduces dynamic workflows that orchestrate tens to hundreds of parallel subagents for complex tasks like codebase-wide bug hunts, large migrations, and multi-angle verification. UltraCode mode auto-triggers workflows on hard problems.