Arshes CLI

A CLI tool that works with the Arshes iOS app to edit and preview shaders from your PC. Supports file-watching mode (serve) and MCP server mode (mcp) for AI agent integration.

Arshes CLI implements the Arshes Remote Editor Protocol v1 for communication with the Arshes iOS app over WebSocket.

Installation

go install github.com/shivaduke28/arshes-cli/cmd/arshes@latest

Requirements

• Go 1.24 or later
• Arshes iOS app
• PC and iPhone on the same local network (Wi-Fi)

Serve

Start a WebSocket server that watches a shader file and sends updates to iPhone in real-time.

# Start server (auto-generates a new shader file)
arshes serve

# Specify an existing shader file
arshes serve shader.slang

# Custom port
arshes serve --port 9000

# Enable logging to arshes.log
arshes serve --log

If no file is specified, a timestamped file (e.g., shader_20260125200800.slang) is created automatically.

Connecting from iPhone

1. Open the Remote Editor feature in the Arshes iOS app
2. Enter the server address (e.g., 192.168.1.5:10080) and connect

To restrict access, set --token (or ARSHES_TOKEN env var) on the server and configure the same token in the Arshes app. The token is verified during the WebSocket handshake.

Once connected, saving the shader file on your PC automatically sends it to iPhone for compilation and preview.

Flags

Flag	Description
-p, --port int	Server port (default: 10080)
--token string	Authentication token for client connections (can also be set via ARSHES_TOKEN env var)
--log	Enable logging to arshes.log

MCP

Start an MCP (Model Context Protocol) server with a WebSocket bridge to iPhone. This allows AI agents like Claude Code to compile and preview shaders on the connected iPhone.

arshes mcp

# Custom port
arshes mcp --port 9000

# Use Streamable HTTP transport (for remote deployment)
arshes mcp --transport http

# With token authentication (recommended for remote deployment)
arshes mcp --transport http --token mytoken
# Or via environment variable
ARSHES_TOKEN=mytoken arshes mcp --transport http

Transport Modes

Mode	Description
stdio (default)	Communicates via stdin/stdout. The AI agent launches and manages the process.
http	Communicates via Streamable HTTP. Both the MCP endpoint (/mcp) and the WebSocket endpoint (/) are served on the same port.

MCP Tools

Tool	Description
compile_shader	Send shader code to iPhone for compilation. Accepts code (inline) or file (path to .slang file). Optionally save rendered image to image path.
get_shader	Get the last synced shader code from iPhone.
get_shader_spec	Get the Slang shader API specification (available uniforms, parameter attributes, entry point signature).
get_status	Get iPhone connection status and WebSocket server address.

Configuration

stdio (default):

Add to your .mcp.json:

{
  "mcpServers": {
    "arshes": {
      "command": "arshes",
      "args": ["mcp"]
    }
  }
}

Streamable HTTP:

Start the server first by arshes mcp --transport http, then add to your .mcp.json:

{
  "mcpServers": {
    "arshes": {
      "type": "http",
      "url": "http://localhost:10080/mcp"
    }
  }
}

Streamable HTTP with authentication:

When --token is set, the MCP endpoint requires Authorization: Bearer <token> header:

{
  "mcpServers": {
    "arshes": {
      "type": "http",
      "url": "https://your-app.fly.dev/mcp",
      "headers": {
        "Authorization": "Bearer mytoken"
      }
    }
  }
}

Example Shader

[shader("fragment")]
float4 fragmentMain(float2 uv : TEXCOORD) : SV_Target {
    return float4(uv, 0.5, 1.0);
}