act-sdk 0.3.0 - Docs.rs

Rust SDK for the ACT protocol — define tools as plain functions, compile to .wasm, serve over MCP or HTTP.

Quick start

use act_sdk::prelude::*;

#[derive(Deserialize, JsonSchema)]
struct GreetArgs {
    name: String,
}

#[act_component(name = "greeter", version = "0.1.0", description = "A greeter")]
mod component {
    use super::*;

    #[act_tool(description = "Say hello", read_only)]
    fn greet(args: GreetArgs) -> ActResult<String> {
        Ok(format!("Hello, {}!", args.name))
    }
}

cargo build --target wasm32-wasip2 --release
act serve target/wasm32-wasip2/release/greeter.wasm
# or
act mcp target/wasm32-wasip2/release/greeter.wasm

Workspace crates

Crate	Description
`act-sdk`	SDK with `#[act_component]` and `#[act_tool]` macros
`act-sdk-macros`	Proc macro implementation
`act-types`	Shared types, CBOR utilities, JSON-RPC and MCP wire formats

Features

#[act_tool] — derive tool metadata, JSON Schema, and CBOR serialization from a plain Rust function
Streaming — mark tools with streaming and use ActContext to emit progress events
Typed config — define a config struct, get automatic JSON Schema generation and validation
MCP + HTTP — same .wasm works with both transports, zero code changes

Examples

Example	What it shows
`hello-sdk`	Basic tools, streaming with `ctx.send_progress()`
`config-sdk`	Typed component configuration
`http-client-sdk`	Outbound HTTP via WASI
`hello-world`	Minimal component without SDK (raw wit-bindgen)
`http-client`	Raw HTTP client without SDK
`counter`	Stateful counter

Building

Requires Rust nightly (for wasm32-wasip2 async support):

# Build all examples
cargo build --target wasm32-wasip2 --release

# Run tests (host-side, not wasm)
cargo test --target x86_64-unknown-linux-gnu

See rust-toolchain.toml for the pinned toolchain.

License

Licensed under either of Apache License, Version 2.0 or MIT License at your option.