ACL - Agent Configuration Language

A lightweight, typed configuration language for agent configurations. ACL is designed for defining structured agent behaviors with blocks, attributes, and function calls.

Features

• HCL-like Syntax: Familiar block-based structure with attributes and nested blocks
• Typed Values: Strings, numbers, booleans, lists, objects, null, and function calls
• Function Calls: Built-in support for env(), concat(), and custom functions
• Bidirectional: Parse ACL text to AST, generate AST back to text
• Multi-platform SDK: Rust crate and Node.js/TypeScript SDK

Syntax

providers "openai" {
    api_key = env("OPENAI_API_KEY")
    base_url = "https://api.openai.com/v1"
}

default_model = "gpt-4"

settings {
    temperature = 0.7
    max_tokens = 2000
}

nested "label" {
    deeply {
        value = "supported"
    }
}

Installation

Rust

[dependencies]
a3s-acl = "0.1.0"

use acl::{parse, generate, string, number, boolean, BlockBuilder, DocumentBuilder};

let doc = parse(r#"
    name = "test"
    count = 42
"#)?;

let output = generate(&doc);

Node.js / TypeScript

npm install @a3s-lab/acl

import { parse, generate, string, number, boolean, BlockBuilder } from '@a3s-lab/acl';

const doc = parse(`
    providers "openai" {
        api_key = env("OPENAI_API_KEY")
    }
`);

const output = generate(doc);

API

Parse

let doc = parse(input: &str) -> Result<Document, ParseError>

const doc = parse(input: string): Document

Generate

let output = generate(doc: &Document) -> String

const output = generate(doc: Document): string

Value Constructors

Function	Rust	TypeScript
String	string("x")	string("x")
Number	number(42.0)	number(42)
Boolean	boolean(true)	boolean(true)
Null	null_value()	nullValue()
List	list(vec![...])	list([...])
Function Call	call("env", vec![...])	call("env", [...])

Builders

let block = BlockBuilder::new("config")
    .label("primary")
    .attr("name", string("test"))
    .attr("count", number(42))
    .nested_block(nested_block)
    .build();

let doc = DocumentBuilder::new()
    .block(block)
    .build();

const block = new BlockBuilder('config')
    .label('primary')
    .attr('name', string('test'))
    .attr('count', number(42))
    .nestedBlock(nestedBlock)
    .build();

const doc = new DocumentBuilder()
    .block(block)
    .build();

Value Types

Kind	Description
String	Quoted text: "hello"
Number	Integer or float: 42, 3.14
Bool	Boolean: true, false
Null	Null value: null
List	Ordered collection: [1, 2, 3]
Object	Key-value pairs: {key = value}
Call	Function invocation: env("VAR")

License

MIT