Ax Signatures For Java

This skill helps an agent write Java code with the generated Ax package dev.axllm:ax. Use the generated package API, examples, and manifests; do not import TypeScript-only APIs unless you are editing the TypeScript package.

When To Use

• Declare input and output contracts with native generated-package APIs.
• Generate JSON-schema-compatible shapes for outputs, tools, prompts, and validation.
• Keep Standard Schema and TypeScript-only helper libraries out of generated-language code.

Package Facts

• Language: Java.
• Package: dev.axllm:ax.
• Package API docs: API.md and axir-api.json.
• Capability manifest: axir-capabilities.json.
• Runnable examples: examples/.
• Real network support: yes.
• Scripted no-key transport support: yes.
• Runtime profiles: javascript-quickjs, python-pyodide.

Core Pattern

import dev.axllm.ax.*;

AxSignature sig = Ax.s("question:string -> answer:string");
var schema = sig.toJsonSchema("outputs", java.util.Map.of());

More Patterns

Simple string contract

Use the string form when field names and types are enough.

AxGen program = Ax.ax("questionText:string -> answerText:string");

Bounded class output

A class field constrains the model to a known label set.

AxGen router = Ax.ax(
    "messageText:string -> routeClass:class \"support, sales, engineering\"");

Fluent constraints

Java exposes the native fluent builder for validation constraints and objects.

AxSignature signature = Ax.f().call()
    .input("contactEmail", Ax.f().string("Contact email").email())
    .output("partySize", Ax.f().number("Guests").min(1).max(12))
    .output("bookingCode", Ax.f().string().regex("^[A-Z]{3}-\\d{4}$", "ABC-1234"))
    .build();

JSON schema

Render the output contract for tools, validators, or external consumers.

var schema = signature.toJsonSchema("outputs", java.util.Map.of());

Reuse the signature

Pass one built signature into AxGen and call it like any other program.

AxGen program = Ax.ax(signature);
var output = program.forward(client, inputs);

Start from the complete programs under examples/, then browse the larger gallery at https://axllm.dev/java/subsystems/s/.

Relevant API Surface

• Signatures: Ax.s, Ax.f, AxSignature
• Tools: Ax.fn, Tool

Guardrails

• Start from package examples for exact native syntax before inventing a new call shape.
• Use provider-api examples only when the user explicitly has provider credentials available.
• Use no-key examples for deterministic local checks and provider request mapping.
• Treat AxIR as the source of generated package truth: if package docs disagree with source code, update the compiler and regenerate packages.
• Do not copy repo-maintainer skills from tools/*/skills/ into user packages.