New AI models for coding: hosted and local picks for October 2026

The new AI models for coding worth testing this month are Claude Opus 5.5 and GPT-6.1 Sol if you work through an API, and Flint, Nanbeige4.3-33B or the upcoming Kimi K3.1 Pro weights if you want something that runs on your own hardware. Below is what each vendor says the model is for, with dates as of October 28, 2026, and no benchmark tables, because the scores published so far are the vendors' own.

To follow coding-relevant launches without reading six changelogs, ClaudeGPT Si, a free and independent AI news site, writes up each release with its sources in its models section.

Hosted models

These run on the vendor's servers. You call them from an API, an IDE plugin or a coding agent.

1. Claude Opus 5.5 (Anthropic, September 22). Anthropic's models overview describes it as the model for long-running agentic coding and knowledge work, and tells developers to start with it for most workloads. Its sibling Sonnet 5.5 (September 28) trades some depth for speed, and Haiku 5.5 (October 7) is the pick for fast, high-volume calls such as routing or extraction inside a tool.

2. GPT-6.1 Sol (OpenAI, September 29). OpenAI's API changelog lists it for complex coding and professional work. The same changelog shows GPT-6.1 Terra on October 26, a smaller model aimed at visual reasoning and computer use, which can suit UI automation better than a large coding model.

3. Gemini 4 Argon (Google, October 13). Google's launch post calls it its latest frontier model. Developers reach it through the paid tier of the Gemini API in AI Studio, and Google also offers it in Antigravity, its agent-first development tool.

Local and open-weight models

These ship weights you can download, so code never has to leave your machine.

4. Flint (Recursive, October 23). Built for coding agents: exploring a codebase, fixing bugs, adding features and writing tests. Its model card lists 39.8B total parameters with about 2.5B active per token, and an Apache 2.0 licence. ClaudeGPT Si's Flint report notes that it works with llama.cpp, Ollama, vLLM and SGLang.

5. Nanbeige4.3-33B (Nanbeige, October 24). An Apache-2.0 model of about 33B parameters with a 512K context window, aimed at agentic coding and office-style tasks in English and Chinese.

6. Kimi K3.1 Pro (Moonshot AI, October 23). Live now on the Kimi API and in Kimi Code. Moonshot says the full weights will be published by November 4, so it moves into this group next week.

Which one to try first

Run your own repository through two candidates before you switch. Vendor benchmark claims for all six were made on their own setups, and ClaudeGPT Si flags in each story where no independent test exists yet.

A note on privacy

The local models have one clear advantage: your source code and secrets stay on your machine. If you paste production config or a customer record into a hosted chat window, it goes to that provider's servers under its own data terms. The same thinking applies to small utilities like JSON formatters and token decoders; AyeTab runs those in the browser for that reason.

Where to read about the next release

Model launches now land weekly. ClaudeGPT Si dates each fact, links the model card or changelog it used, and offers an RSS feed you can drop into a reader. When you need the exact model ID or a parameter name, go to the vendor's own docs; a news write-up points you there but does not replace them.