Ax Signatures For C++

Use when writing C++ code with axllm for string signatures, field descriptors, JSON schema output, validation, and typed tool argument shapes.

Install

Install only this skill for C++:

npx skills add https://ax-llm.github.io/ax/cpp/ --skill 'ax-cpp-signature'

Published skill file: ax-cpp-signature/SKILL.md.

Source

• Source: packages/cpp/skills/ax-cpp-signature/SKILL.md
• Version: 23.0.5

Skill Instructions

This skill helps an agent write C++ code with the generated Ax package axllm. 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: C++.
• Package: axllm.
• 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

#include "axllm/axllm.hpp"

auto sig = axllm::s("question:string -> answer:string");
auto schema = axllm::to_json_schema(axllm::Core::get(sig, "outputs"));

More Patterns

Simple string contract

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

auto program = axllm::ax("questionText:string -> answerText:string");

Bounded class output

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

auto router = axllm::ax(
    "messageText:string -> routeClass:class \"support, sales, engineering\"");

Native constraints

C++ exposes the generated record surface for constrained fields.

auto party_type = axllm::Core::record_new(
    "FieldType",
    axllm::object({
      {"name", "number"},
      {"minimum", 1},
      {"maximum", 12},
    }));

Validate and render

Validate the native record, then render its output fields as JSON schema.

axllm::Core::validate_signature(signature);
auto schema = axllm::to_json_schema(
    axllm::Core::get(signature, "outputs"),
    "outputs");

Reuse the signature

Pass the native signature record directly into AxGen.

axllm::AxGen program = axllm::ax(signature);
auto output = program.forward(client, inputs);

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

Relevant API Surface

• Signatures: axllm::s, axllm::FieldType, axllm::AxSignature
• Tools: axllm::Tool, axllm::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.