Show HN: A modern C++20 AI SDK (GPT‑4o, Claude 3.5, tool‑calling)

56•cauchyk•7mo ago

Hi all,

I’m hacking on new features for the ClickHouse native client and wanted the same “just call the model” ergonomics JavaScript and Python now enjoy. It didn’t exist for modern C++, so I wrote one.

ai‑sdk‑cpp (Apache‑2.0) gives you:

- Unified calls to OpenAI (GPT‑4o) and Anthropic (Claude 3.5) with a single C++20 API. - Streaming, multi‑turn chat, error handling—all std::optional/std::variant, no macros. - Tool calling (function‑calling) so the model can hit real APIs; sync or async, runs in parallel.

The tricky bit: C++ still lacks real reflection, so mapping plain functions → JSON schemas isn’t as automatic as, say, TypeScript decorators. I’d love fresh eyes on that part. Try the examples and tell me where it feels clunky. This is inspired by Vercel's AI SDK [1], and litellm [2].

Repo live here: https://github.com/ClickHouse/ai-sdk-cpp, feedback welcome!

[1] https://github.com/vercel/ai [2] https://github.com/BerriAI/litellm

Comments

rubymamis•7mo ago

Very nice! I might get inspire for my own Qt C++ LLM client[1]. Do you plan to add streaming Markdown parsing? It's a challenging problem that was very fun implementing for Vox -> it allows parsing code blocks and other such advance/custom blocks (I created a custom 'tool' block) without re-rendering. My implementation is currently tied to Qt's C++ but I might make it more generic and open source it.

[1] https://www.get-vox.com/

pjmlp•7mo ago

While you will need C++26 for real reflection, you could use some of the libraries that make do with what is already possible via concepts, if constexpr and type traits.

For example,

- https://www.boost.org/doc/libs/latest/doc/html/boost_pfr.htm...

- https://github.com/getml/reflect-cpp

And kudos for using modern C++.

sylware•7mo ago

I was wondering, has anybody tried to use AI to port c++ to C?

bergesenha•7mo ago

The json library 'glaze' has working compile time reflection for MSVC, Clang and GCC using some tricks with aggregate initializable structs. In addition to being a performant json library, it comes with the functions glz::apply and glz::to_tie which I used for general tool calling straight from deserialized json.

fsloth•7mo ago

“mapping plain functions → JSON schemas”

In general I’ve found it’s much better in C++ to be verbose and plain rather than succinct and elegant.

Javascript and python lack typing so being pithy&clever in those languages has entirely different implications than in C++.

“How can I express this in the most basic, unsurprising and plainspoken C++” is usually the right question to ask. “How can I make this more elegant” is a question better suited for other languages imho.

The best C++ API when in doubt is a C style API.

N_Lens•7mo ago

Agreed! C++ is a powerful language but full of footguns.

Show HN: I saw this cool navigation reveal, so I made a simple HTML+CSS version

Kinda Surprised by Seadance2's Moderation

I Write Games in C (yes, C)

Django scales. Stop blaming the framework (part 1 of 3)

Malwarebytes Is Now in ChatGPT

Thoughts on the job market in the age of LLMs

Show HN: Stacky – certain block game clone

AIII: A public benchmark for AI narrative and political independence

SectorC: A C Compiler in 512 bytes

The API Is a Dead End; Machines Need a Labor Economy

Digital Iris [video]

New wave of GLP-1 drugs is coming–and they're stronger than Wegovy and Zepbound

Convert tempo (BPM) to millisecond durations for musical note subdivisions

Show HN: Tasty A.F.

The Contagious Taste of Cancer

U.S. Jobs Disappear at Fastest January Pace Since Great Recession

Bithumb mistakenly hands out $195M in Bitcoin to users in 'Random Box' giveaway

Beyond Agentic Coding

OpenClaw ClawHub Broken Windows Theory – If basic sorting isn't working what is?

OpenBSD Copyright Policy

OpenClaw Creator: Why 80% of Apps Will Disappear

What Happens When Technical Debt Vanishes?

AI Is Finally Eating Software's Total Market: Here's What's Next

Computer Science from the Bottom Up

Show HN: A toy compiler I built in high school (runs in browser)

You don't need Mac mini to run OpenClaw

Learning to Reason in 13 Parameters

Convergent Discovery of Critical Phenomena Mathematics Across Disciplines

Ask HN: Will GPU and RAM prices ever go down?

From hunger to luxury: The story behind the most expensive rice (2025)