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