Choosing the right AI model to power your Autohive agent

When building an agent in Autohive, you pick which AI model runs it. That choice matters. Different models are better at different things, and picking the wrong one for the job means slower results, higher costs, or outputs that miss the mark.

OpenAI, Anthropic, Google, and xAI (now part of SpaceX under the SpaceXAI brand) have all shipped major updates in 2025 and 2026. There are also strong open-source options now available through Fireworks. This guide cuts through the noise and tells you what each model is actually good at. If you’re not sure where to start on model selection more broadly, our post on why one model shouldn’t run everything is worth reading alongside this one.

The providers

OpenAI

OpenAI brought large language models to the mainstream and remains one of the most widely used providers. Their models tend to be reliable and consistent, with strong instruction-following and broad integration support. You’ve probably used them through ChatGPT or Microsoft Copilot.

Anthropic

Anthropic was founded by former OpenAI researchers and focuses on building AI that behaves predictably and safely. Their Claude models use constitutional AI, a training approach where the model follows a set of guiding principles rather than just responding to prompts. Claude models are well regarded for analytical work, long-context tasks, and compliance-sensitive environments. Anthropic also developed the Model Context Protocol (MCP), which is becoming a standard for how agents connect to tools.

Gemini

Google’s Gemini models are developed by DeepMind and baked into products like Gmail, Docs, and Android. They combine strong language understanding with Google’s knowledge and reasoning capabilities. Gemini models are particularly good with multimodal inputs and high-volume, document-heavy workflows.

xAI

Founded by Elon Musk in 2023, xAI was acquired by SpaceX in February 2026 and rebranded as SpaceXAI that July. Grok, the model line, and the X platform now sit under SpaceX’s balance sheet, though Autohive still lists the provider as xAI in the model picker. Their Grok models are built with less content filtering than most providers, which makes them useful for candid, unfiltered outputs. Grok also pulls real-time data from X, giving it current context that other models don’t have.

Open-source models via Fireworks

Autohive also supports a selection of open-source models served through Fireworks, a high-performance AI inference platform. These models come from different labs and offer a compelling alternative to closed-source providers, particularly for teams that want strong performance at lower cost. Because they’re open-weight, they tend to be more transparent and easier to inspect than proprietary options.

All open-source models in Autohive run through AWS. Your data never goes directly to the source labs. Requests are routed through a secure AWS environment, so the same data security standards apply here as they do across the rest of the platform.

Current models

OpenAI (GPT-6.1 Sol, GPT-6 Astra, GPT-6 Luna)

OpenAI replaced its GPT-5.6 line with GPT-6 in September.

GPT-6.1 Sol (Released September 29, 2026, now Autohive’s default model) The model most agents should start on. It’s reliable, quick, and strong at coding, document work, and everyday business tasks. A smarter and cheaper-to-run version of GPT-6 Sol. Read more in our GPT-6.1 Sol explainer.

GPT-6 Astra (Released September 3, 2026) OpenAI’s most powerful model, built for the hardest coding and agent work. It costs a lot more than Sol, so use it only when Sol isn’t enough.

GPT-6 Luna (Released September 22, 2026) The cheapest GPT-6 model. Quick and low cost, so it suits high-volume jobs like sorting, tagging, and pulling out data. Not built for long conversations.

Pros:

• Reliable, consistent, structured output
• GPT-6.1 Sol is a strong default for most agents
• Wide ecosystem support and integrations

Cons:

• Astra costs several times more than Sol
• Luna isn’t suited to long, complex conversations
• Proprietary, so customization is limited

Best for:

General-purpose agents that need reliable output. Email drafting, ticket triage, follow-up automation, coding tasks. Use Luna for high-volume simple work, Sol as the default, and Astra for the hardest jobs.

Anthropic (Claude Opus 5.5, Claude Sonnet 5.5, Claude Haiku 5.5, Claude Fable 5.1)

Claude Opus 5.5 (Released September 22, 2026) Anthropic’s most capable model. It replaces Opus 5, costs 20% less, and runs over 30% faster. Best for the hardest, multi-step agent work. Read more in our Claude Opus 5.5 announcement.

Claude Sonnet 5.5 (Released September 28, 2026) The everyday Claude model. It replaces Sonnet 5, runs over 30% faster, and costs up to 30% less for most work, according to Anthropic. A good choice for day-to-day agents, bug fixes, and building documents, slides, and spreadsheets.

Claude Haiku 5.5 (Released October 7, 2026) The fastest and cheapest Claude model. It replaces Haiku 4.5 and is far more capable. Good for quick, high-volume jobs like triage, classification, and short summaries.

Claude Fable 5.1 (Released September 1, 2026) Replaces Fable 5 with Opus-level intelligence at Sonnet-level speed, and it costs less than Fable 5. Best for legal, scientific, and complex coding work.

Pros:

• Strong on long, multi-step tasks and large inputs
• Strong safety controls for compliance-sensitive work
• A model for every budget, from Haiku 5.5 up to Opus 5.5

Cons:

• Opus 5.5 and Sonnet 5.5 can cost more than expected on the hardest jobs, so test your real costs
• Fable 5.1 costs more than Opus 5.5, so save it for the work it’s best at
• Vague prompts can lead to overly cautious responses

Best for:

Analytical tasks, multi-step workflows, structured output, and compliance-heavy environments. Use Haiku 5.5 for speed and low cost, Sonnet 5.5 for everyday agents, Opus 5.5 for the hardest problems, and Fable 5.1 for legal, scientific, and complex coding work.

Google Gemini (Gemini 4 Argon, Gemini 3.7 Flash, Gemini 3.6 Flash, Gemini 3.5 Flash-Lite)

Gemini 4 Argon (Introduced September 30, 2026, generally available October 13, 2026) Google’s most powerful model, a step up from the Flash models. Strong at coding, finance and legal work, and long multi-step tasks, and it handles text, images, video, audio, and PDFs. It costs more than the Flash models, and Google’s API price doubles on December 1. See our Gemini 4 Argon post for the details.

Gemini 3.7 Flash (Added August 18, 2026) A fast, low-cost model for everyday agent work. It’s very close to 3.6 Flash, so test both and keep whichever suits your task.

Gemini 3.6 Flash (Released July 23, 2026) A fast, affordable all-rounder for coding help, document analysis, and tasks with images or other media. A solid default when you need more than basic text work but not top-tier reasoning. Read more in our Gemini Flash models announcement.

Gemini 3.5 Flash-Lite (Released July 23, 2026) The fastest, cheapest Gemini model. Built for high-volume work like classification, extraction, and summarization. A strong pick for worker roles in multi-agent setups and scheduled jobs.

Pros:

• Argon gives you a top-tier option, and the Flash models are fast and low cost
• Works with text, images, audio, and video
• Tight integration with Google Cloud

Cons:

• Argon costs more than the Flash models, and its price doubles on December 1
• Tone can be formal, and less flexible than Claude or GPT for creative tasks
• Flash-Lite trades some reasoning ability for speed

Best for:

High-volume agents working with long documents, CRM enrichment, knowledge base summarization, and data tagging. Use Flash-Lite for worker roles and scheduled jobs, the Flash models for everyday work, and Argon when a task needs more reasoning and the extra cost is worth it.

xAI Grok (Grok 4.7, Grok 4.6, Grok 4.5, Grok 4.3)

xAI now operates as SpaceXAI following SpaceX’s acquisition in February 2026, but kept shipping through the change, and Grok models still appear under xAI in Autohive’s model picker.

Grok 4.7 (Released September 21, 2026) The newest and most capable Grok, strong at agentic coding. It tends to write a lot, so check your real run costs before switching a production agent over.

Grok 4.6 A solid mid-tier option that handles images, tools, and reasoning in a single model.

Grok 4.5 Sits below 4.6. xAI cut its cached pricing by 40% on July 28, 2026, which makes long, back-and-forth conversations cheaper to run. See our Grok 4.5 pricing post for the numbers.

Grok 4.3 (Released April 2026) The established production model. A good balance of accuracy and speed for demanding tasks that don’t need the newest capability.

Pros:

• Grok 4.7 is a real step up for agentic coding
• Real-time X data gives Grok current context other models lack
• Less-filtered outputs are useful for honest brainstorming and internal content

Cons:

• Grok 4.7 writes a lot, so costs can run higher than the price suggests
• Unpredictable when you need tight control over tone or formatting
• Not suitable for customer-facing or compliance-heavy work
• Fewer integrations than OpenAI or Google

Best for:

Internal agents focused on coding, ideation, feedback, and anything where real-time X data or a candid tone is more useful than filtered output. Start with Grok 4.7 for the newest capability, Grok 4.6 as a cheaper all-rounder, or Grok 4.5 for long conversations.

Open-source via Fireworks (DeepSeek V4 Pro, DeepSeek V4.1 Flash, Kimi K2.6, Kimi K3, GLM 5.2, Qwen 3.7 Plus)

These models come from different AI labs and are served through Fireworks. They’re open-weight, meaning the model weights are publicly available. On key benchmarks, the best of these now compete directly with top closed-source models.

DeepSeek V4 Pro (Released April 24, 2026, by DeepSeek) One of the strongest open-weight models for coding. A good pick when you want top coding performance at a lower cost.

DeepSeek V4.1 Flash (1017 build, released October 17, 2026) Replaces DeepSeek V4 Flash. A fast, very low-cost model for coding, automation, and tool-heavy work. It now accepts images too.

Kimi K2.6 (By Moonshot AI) A capable open-source model for agentic and coding tasks.

Kimi K3 (By Moonshot AI) Moonshot AI’s newer Kimi. It handles longer inputs and images, which K2.6 can’t. Worth testing against K2.6 for agentic and coding tasks.

GLM 5.2 (By Zhipu AI) A reliable open-weight model with strong coding and reasoning.

Qwen 3.7 Plus (By Alibaba) An all-rounder that’s strong at coding, reasoning, and general tasks, with broad community support.

Pros:

• More transparent and inspectable than proprietary models
• Strong coding performance at a lower cost
• Competitive with top closed-source models on many benchmarks

Cons:

• Less integrated ecosystem support than the major closed-source providers
• Safety filtering and behaviour varies across labs
• Better suited to teams comfortable testing and evaluating models

Best for:

Teams that want strong coding and reasoning with more transparency, or want to diversify away from a single closed-source provider. DeepSeek V4.1 Flash suits high-volume, tool-heavy automation where cost per run matters.

Quick reference

As you build more agents, you’ll likely find that different models work better for different jobs. Autohive lets you switch models, test performance, and adjust as you go. The goal isn’t finding the single best model. It’s finding the right one for what you’re building right now.

We’ll keep updating this guide as new models ship. If there’s a model or provider you’d like to see supported, let us know.

Build your own AI agents on Autohive, the no-code AI platform.

Previous models on Autohive

These models were featured in earlier versions of this guide. They’ve been replaced by newer releases from the same providers, but you may still encounter them referenced in older agent configurations.

OpenAI: GPT-6 Sol, GPT-5.6 Sol, GPT-5.6 Terra, GPT-5.6 Luna, GPT-5.5, GPT-5.4, GPT-5.4 Mini, GPT-5.4 Nano, GPT-5, GPT-4.1, o4-mini, o3

Anthropic: Claude Sonnet 5, Claude Opus 5, Claude Fable 5, Claude Haiku 4.5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, Claude Opus 4.1, Claude Sonnet 4.6, Claude Sonnet 4.5, Claude 3.7 Sonnet

Google: Gemini 3.1 Pro, Gemini 2.5 Pro, Gemini 2.5 Flash, Gemini 3.5 Flash, Gemini 3.1 Flash-Lite

xAI: Grok 4.20, Grok 4, Grok 3, Grok 3 Mini

Open source: DeepSeek V4 Flash (0731 build)