AxGen Structured Generation For C++

Use when writing C++ code with axllm for AxGen programs, forward calls, indexed multi-sampling, result pickers, streaming, tools, assertions, traces, usage, and output parsing.

Install

Install only this skill for C++:

Shell

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

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

Source

Source: packages/cpp/skills/ax-cpp-gen/SKILL.md
Version: 24.0.17

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

Build a structured generation program from a signature.
Attach typed tools or MCP-derived tools to a generation call.
Generate multiple validated structured samples and select a winner with a native callback.
Use package examples for no-key scripted clients and provider-api calls.

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

C++

auto program = axllm::ax("question:string -> answer:string");
auto out = program.forward(llm, { {"question", "What is Ax?"} });

Provider Forward Options

AxGen merges constructor and per-call forward options before invoking the provider. Provider-facing keys such as promptCacheKey, sessionId, and contextCache therefore reach the chat request without being copied into program inputs. Per-call values override constructor defaults.

structuredOutputMode / structured_output_mode accepts auto, native, function, or json_object. Auto follows the selected profile/model ordering, with the provider-neutral singleton string/code JSON-object optimization. Explicit modes must be advertised and fail before transport otherwise. JSON-object mode retains exact-shape prompting, strict parsing, and one bounded correction retry without a synthetic __axOutput tool.

Multi-Sampling

Set sampleCount / sample_count to request N provider candidates. Core parses and validates every candidate, preserving each provider result index.
Without a result picker, AxGen returns candidate 0. A result picker receives all { index, sample } structured candidates and returns the winning list index; Core rejects an index outside 0..N-1.
Native callback surface: set_sample_count / set_result_picker.
OpenAI-compatible Chat and Gemini map multi-sampling to n and candidateCount. Anthropic rejects n > 1 explicitly.

Relevant API Surface

AxGen: axllm::ax, axllm::AxGen
Tools: axllm::Tool, axllm::Tool
MCP: axllm::AxMCPClient, axllm::AxMCPStreamableHTTPTransport, axllm::AxMCPStdioTransport

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.