rvagent-wasm

WASM bindings for rvAgent — run AI agents entirely in the browser or Node.js.

Features

• WasmAgent — Full agent execution in browser/Node.js with conversation history
• WasmMcpServer — MCP JSON-RPC server running in the browser (no backend required)
• Virtual Filesystem — In-memory file operations for sandboxed execution
• Gallery System — Built-in agent templates with RVF container export
• Zero Dependencies — Runs entirely client-side via WebAssembly

Installation

# Build from source
cd crates/rvAgent/rvagent-wasm
wasm-pack build --target web

# Or use the pre-built package
npm install rvagent-wasm  # (Not yet published)

Usage

WasmAgent

import init, { WasmAgent } from 'rvagent-wasm';

await init();

// Create an agent
const agent = new WasmAgent(JSON.stringify({
  model: "anthropic:claude-sonnet-4-20250514",
  name: "my-agent",
  instructions: "You are a helpful coding assistant.",
  max_turns: 50
}));

// Connect a model provider (calls your LLM API)
agent.set_model_provider(async (messagesJson) => {
  const messages = JSON.parse(messagesJson);
  const response = await fetch('/api/chat', {
    method: 'POST',
    body: JSON.stringify({ messages })
  });
  return (await response.json()).content;
});

// Send a prompt
const result = await agent.prompt("Write a hello world function");
console.log(result.response);

// Execute tools directly
agent.execute_tool('{"tool": "write_file", "path": "hello.js", "content": "console.log(\"Hello!\");"}');

// Check state
console.log(agent.turn_count());      // 1
console.log(agent.file_count());      // 1
console.log(agent.get_todos());       // []

WasmMcpServer

Run an MCP server entirely in the browser:

import init, { WasmMcpServer } from 'rvagent-wasm';

await init();

const mcp = new WasmMcpServer("rvagent-wasm");

// Handle MCP JSON-RPC requests
const response = mcp.handle_request(JSON.stringify({
  jsonrpc: "2.0",
  id: 1,
  method: "initialize",
  params: {}
}));

// List available tools
const tools = mcp.list_tools();

// Call a tool
const result = mcp.call_tool("write_file", JSON.stringify({
  path: "demo.txt",
  content: "Hello from WASM!"
}));

Gallery System

Access built-in agent templates:

// List all templates
const templates = mcp.handle_request(JSON.stringify({
  jsonrpc: "2.0",
  id: 1,
  method: "gallery/list",
  params: {}
}));

// Search templates
const searchResults = mcp.handle_request(JSON.stringify({
  jsonrpc: "2.0",
  id: 2,
  method: "gallery/search",
  params: { query: "coding assistant" }
}));

// Load a template
const loaded = mcp.handle_request(JSON.stringify({
  jsonrpc: "2.0",
  id: 3,
  method: "gallery/load",
  params: { id: "claude-code" }
}));

Available Tools

| Tool | Description | |------|-------------| | read_file | Read file from virtual filesystem | | write_file | Write file to virtual filesystem | | edit_file | Apply string replacement to a file | | list_files | List all files in virtual filesystem | | write_todos | Manage todo list |

Note: OS-level tools (execute, glob, grep) are intentionally omitted as they require system access unavailable in the browser sandbox.

MCP Methods

| Method | Description | |--------|-------------| | initialize | Initialize MCP connection | | ping | Health check | | tools/list | List available tools | | tools/call | Execute a tool | | resources/list | List virtual filesystem as resources | | prompts/list | List prompts from active template | | gallery/list | List all agent templates | | gallery/search | Search templates by query | | gallery/get | Get template details | | gallery/load | Load template as active config | | gallery/configure | Apply config overrides | | gallery/categories | List template categories |

API Reference

WasmAgent

| Method | Description | |--------|-------------| | new(configJson) | Create agent from JSON config | | set_model_provider(callback) | Set JS callback for LLM calls | | prompt(input) | Send prompt, get response (async) | | execute_tool(toolJson) | Execute a tool directly | | get_state() | Get conversation state as JSON | | get_todos() | Get todo list as JSON | | get_tools() | Get available tools | | reset() | Clear state and start fresh | | version() | Get crate version | | name() | Get agent name | | model() | Get model identifier | | turn_count() | Get current turn count | | is_stopped() | Check if agent is stopped | | file_count() | Get virtual filesystem file count |

WasmMcpServer

| Method | Description | |--------|-------------| | new(name) | Create MCP server | | handle_request(json) | Handle JSON-RPC request | | list_tools() | Get available tools as JSON | | call_tool(name, paramsJson) | Call tool by name | | gallery() | Get gallery info | | is_initialized() | Check initialization status | | name() | Get server name | | version() | Get server version |

Building

# Install wasm-pack
cargo install wasm-pack

# Build for web
wasm-pack build --target web

# Build for Node.js
wasm-pack build --target nodejs

# Run tests
cargo test
wasm-pack test --headless --chrome

Security

• Request size limit: 100 KB
• Path length limit: 256 characters
• Content length limit: 1 MB
• Path traversal (..) blocked
• Todo count limit: 1000 items

Architecture

rvagent-wasm/
├── src/
│   ├── lib.rs        # WasmAgent — main agent type
│   ├── backends.rs   # WasmStateBackend — virtual filesystem
│   ├── bridge.rs     # JsModelProvider — JS interop
│   ├── gallery.rs    # WasmGallery — template system
│   ├── mcp.rs        # WasmMcpServer — MCP protocol
│   ├── rvf.rs        # RVF container support
│   └── tools.rs      # Tool definitions and executor
└── pkg/              # Built WASM package
    ├── rvagent_wasm.js
    ├── rvagent_wasm.d.ts
    └── rvagent_wasm_bg.wasm

Related Crates

| Crate | Description | |-------|-------------| | rvagent-core | Agent state, graph, config | | rvagent-backends | Backend protocol + implementations | | rvagent-tools | Full tool implementations | | rvagent-mcp | Native MCP client/server | | rvagent-cli | Terminal UI |

License

MIT OR Apache-2.0