Choosing the Right AI Model
Every companion on Eidolon can use a different AI model. This guide covers what's available, what each model is best at, and how to choose the right one for the experience you want.
Quick Recommendations
| Model | Best For… | Tier |
|---|---|---|
| DeepSeek Chat V3 0324 | Low-cost capable model. | Included |
| Gemma 4 26B (MoE) | Very cheap multimodal MoE model with image support. | Included |
| Gemma 4 31B | Compact dense model with strong instruction following and vision. | Included |
| Grok Fast | Snappy, witty conversation and responsive, agentic interactions. | Included |
| Gemini 2.5 Flash | Fast, creative all-rounder with strong instruction following. | Included |
| Mistral Medium | Expressive creative writing and consistent persona maintenance. | Included |
| Mistral Small 4 | Low-cost fast model balancing reasoning and speed. | Included |
| Kimi K2 | Excellent multi-lingual native comprehension. | Included |
| Qwen Models | Vision-language tasks and low-cost reasoning capabilities. | Included |
| DeepSeek V3.2 | Strong general reasoning and instruction following at very low cost. | Included |
| DeepSeek Chat V3.1 | Ultra-low cost conversational model, great for budget-conscious users. | Included |
| GPT-4.1 Mini | Fast, capable everyday model from OpenAI with a 1M token context window. | Included |
| Claude Sonnet 4.6 | High emotional range and nuanced relationship dynamics. | Premium |
| Gemini 2.5 Pro | Large-scale context and deep analytical reasoning. | Premium |
| Kimi K2.5 | Moonshot's powerful reasoning variant. | Premium |
| GPT-5.4 Mini | Balanced cost and quality from OpenAI's GPT-5.4 generation. | Premium |
| GPT-4.1 | OpenAI's previous-gen flagship — strong instruction following and reasoning. | Premium |
| GPT-5.4 | High-capability GPT-5.4 generation model for complex chat and roleplay. | Premium |
| Claude Opus 4.6 | Maximum logical depth and structural reasoning. | Premium |
How to Change Your Model
You can set a different model for each companion individually:
On Android & Web
- Open your companion's Profile.
- The AI Model selector is right on the profile page — choose a model.
- Your companion will use the new model starting with your next message.
On iPhone
- Open your companion's Profile.
- Tap Edit (pencil icon).
- Find the AI Model selector and choose a model.
- Save. Your companion will use the new model starting with your next message.
Models marked Premium require a BYOK (Bring Your Own Key) connection to OpenRouter. Everything else is included during the private preview.
Included Models
These models are included for all users. They cover a wide range of styles and strengths.
Mistral AI Mistral Medium 3.1 (Mistral Medium 3.1)
Includedby Mistral AI
Our default model for new companions. Excellent at creative writing, expressive companion voice, and maintaining persona consistency. A strong balance of quality and speed.
Google Gemini 2.5 Flash (Gemini 2.5 Flash)
Includedby Google
Fast, creative, and excellent at following complex persona instructions. One of the best all-around included options — great for everyday conversations and companions with detailed personalities.
Google Gemma 4 26B A4B (Gemma 4 26B MoE)
Includedby Google DeepMind
A Mixture-of-Experts model with 26B total parameters and only 4B active per token — delivering strong quality at very low cost. Supports image and video input with a 262K context window. A great budget pick with multimodal capability.
Google Gemma 4 31B (Gemma 4 31B)
Includedby Google DeepMind
A compact 31B dense multimodal model with native function calling, configurable reasoning mode, and a 256K context window. Supports text, image, and video input. Strong instruction following at a very competitive price point.
xAI Grok 4 Fast (Grok Fast)
Includedby xAI
Blazingly fast and highly engaging. Excellent at witty conversation, direct interaction, and companions with a sharp sense of humor. One of the best included models for a responsive, agentic experience.
OpenAI GPT-5 Mini (GPT-5 Mini)
Includedby OpenAI
A fast, cost-efficient version of GPT-5. Great for snappy interactions without sacrificing the architectural improvements of the GPT-5 generation.
OpenAI GPT-4.1 Mini (GPT-4.1 Mini)
Includedby OpenAI
A fast, capable model from OpenAI's GPT-4.1 generation with an impressive 1M token context window. Great for companions that handle long conversations or need strong general instruction following without premium pricing.
Moonshot Kimi K2 (Kimi K2)
Includedby Moonshot AI
A highly capable model known for excellent adherence to instructions and strong multilingual support.
Mistral AI Mistral Small 4 (Mistral Small 4)
Includedby Mistral AI
A fast, cost-effective model that excels in reasoning and daily conversational tasks while maintaining Mistral's characteristic stylistic flair.
Mistral AI Mistral Large (Mistral Large)
Includedby Mistral AI
Mistral's flagship model. More analytical and structured than Medium — better for companions with complex, highly detailed personas or those that need to stay closely aligned with specific companion traits.
Alibaba Qwen 3.5 Flash (Qwen 3.5 Flash)
Includedby Alibaba Cloud
The most affordable model in our lineup. Despite the name, Qwen 3.5 Flash is a reasoning model — it "thinks" before responding, which means it's not the fastest in terms of latency. However, its extremely low cost makes it an excellent choice for users who prioritize budget over speed.
Alibaba Qwen 3.5 35B (Qwen 3.5 35B)
Includedby Alibaba Cloud
A compact but capable reasoning model. Good general-purpose performance at an extremely low cost. Works well for everyday conversation and companions that don't need heavy tool usage.
Alibaba Qwen 3 VL (Qwen 3 VL)
Includedby Alibaba Cloud
A vision-language model with strong image understanding. Among the best included options for companions that frequently interact with images and visual content. Not a reasoning model — responses are direct and fast.
DeepSeek V3.2 (DeepSeek V3.2)
Includedby DeepSeek
DeepSeek's latest flagship non-reasoning model. Strong general instruction following, creative writing, and tool use at an extremely low cost. A great budget pick for companions that need capable, well-rounded performance without premium pricing.
DeepSeek Chat V3 0324 (DeepSeek Chat V3 0324)
Includedby DeepSeek
A capable model from DeepSeek that balances performance with affordability, serving as an excellent budget-conscious alternative.
DeepSeek Chat V3.1 (DeepSeek Chat V3.1)
Includedby DeepSeek
The most cost-effective model in our lineup — ideal for users who want to maximize conversation volume at the lowest possible cost. Solid conversational quality for everyday chat companions. Note that image inputs require a description workaround rather than direct vision.
Premium Models
These models require a BYOK key connected to OpenRouter. You pay OpenRouter directly — we don't add any markup.
Moonshot Kimi K2.5 (Kimi K2.5)
Premiumby Moonshot AI • Est. $0.0107 / turn • BYOK • ~$6.42/mo at 20 msg/day
Moonshot's advanced variant that balances powerful multi-turn reasoning and conversational nuance with cost efficiency.
Google Gemini 2.5 Pro (Gemini 2.5 Pro)
Premiumby Google • Est. $0.0375 / turn • BYOK • ~$22.50/mo at 20 msg/day
Google's most capable model. Deeper reasoning and stronger coherence than Flash, especially for companions with complex backstories or nuanced dynamics.
OpenAI GPT-5 (GPT-5)
Premiumby OpenAI • Est. $0.0375 / turn • BYOK • ~$22.50/mo at 20 msg/day
OpenAI's latest flagship. Exceptional at complex roleplay and instruction following.
OpenAI GPT-5.1 (GPT-5.1)
Premiumby OpenAI • Est. $0.0375 / turn • BYOK • ~$22.50/mo at 20 msg/day
Fine-tuned version of GPT-5 with improved coherence and reduced refusals.
OpenAI GPT-4o (GPT-4o)
Premiumby OpenAI • Est. $0.0550 / turn • BYOK • ~$33.00/mo at 20 msg/day
OpenAI's previous-generation flagship. Still very capable and well-liked by many. If you're familiar with ChatGPT, this model will feel familiar.
Anthropic Claude Sonnet 4.6 (Claude Sonnet 4.6)
Premiumby Anthropic • Est. $0.0720 / turn • BYOK • ~$43.20/mo at 20 msg/day
Anthropic's latest and most capable creative model. Excellent at nuanced companion voice and emotional range. An advanced option for maintaining complex relationship dynamics across long conversations.
Anthropic Claude Sonnet 4.5 (Claude Sonnet 4.5)
Premiumby Anthropic • Est. $0.0720 / turn • BYOK • ~$43.20/mo at 20 msg/day
The previous Sonnet generation — still outstanding for creative writing and companion work. Slightly cheaper per token than 4.6 while delivering a very similar quality of experience.
Anthropic Claude Haiku 4.5 (Claude Haiku 4.5)
Premiumby Anthropic • Est. $0.0240 / turn • BYOK • ~$14.40/mo at 20 msg/day
A lightweight, fast model from Anthropic's Claude family. Great for quick, casual conversations. Less depth than the larger Claude models, but significantly faster response times.
OpenAI GPT-5.4 Mini (GPT-5.4 Mini)
Premiumby OpenAI • Est. $0.0195 / turn • BYOK • ~$11.70/mo at 20 msg/day
A cost-effective entry into the GPT-5.4 generation. Delivers solid performance for everyday companions at a lower price point than full GPT-5.4, with a 1M token context window and strong instruction following.
OpenAI GPT-4.1 (GPT-4.1)
Premiumby OpenAI • Est. $0.0440 / turn • BYOK • ~$26.40/mo at 20 msg/day
OpenAI's previous-gen flagship model. Excellent at complex instruction following, detailed persona adherence, and long-context conversations. A proven performer for companions that need reliable, high-quality responses at a lower price than the GPT-5 generation.
OpenAI GPT-5.4 (GPT-5.4)
Premiumby OpenAI • Est. $0.0650 / turn • BYOK • ~$39.00/mo at 20 msg/day
A high-quality model from OpenAI's GPT-5.4 generation with a very large 1M token context window. Strong at complex roleplay, nuanced companion dynamics, and conversations requiring depth. A great mid-tier option between GPT-5 and Claude Sonnet.
Anthropic Claude Opus 4.6 (Claude Opus 4.6)
Premiumby Anthropic • Est. $0.1200 / turn • BYOK • ~$72.00/mo at 20 msg/day
Anthropic's most powerful model. Exceptional reasoning and creative depth. ⚠️ This is one of the most expensive models available — it costs significantly more per message than Sonnet or any included model. Only recommended if you specifically want the absolute maximum quality and are comfortable with the higher API costs.
Anthropic Claude Opus 4.5 (Claude Opus 4.5)
Premiumby Anthropic • Est. $0.1200 / turn • BYOK • ~$72.00/mo at 20 msg/day
Previous-generation Opus. Deep reasoning and creative range. ⚠️ Also one of the most expensive models — similar pricing to Opus 4.6. Consider Sonnet 4.6 for a more balanced quality-to-cost ratio.
xAI Grok 4 (Grok 4)
Premiumby xAI • Est. $0.0720 / turn • BYOK • ~$43.20/mo at 20 msg/day
xAI's full-power model. Stronger reasoning and more creative range than the Fast variants, with a distinctive direct and engaging personality.
About cost estimates: Monthly estimates assume ~20 messages per day for 30 days. For a detailed breakdown of rates and estimates, see our Model Pricing Guide. Actual costs vary based on conversation length and complexity. Prices are set by model providers via OpenRouter and may change at any time. Included models are fully covered by the platform. Premium model costs are charged to your OpenRouter balance.
The Full Model Lineup
| Model | Provider | Style & Strengths | Tier & Strength | Monthly Est. |
|---|---|---|---|---|
| DeepSeek Chat V3 0324 | DeepSeek | Budget, Reasoning | Included • Quality | ~$2.60 |
| Mistral Medium 3.1 | Mistral AI | Creative, Expressive | Included • Default | Included |
| Gemini 2.5 Flash | Fast, Creative | Included • Quality | Included | |
| Grok 4 Fast | xAI | Witty, Engaging | Included • Speed | Included |
| GPT-5 Mini | OpenAI | Snappy, Efficient | Included • Speed | Included |
| GPT-4.1 Mini | OpenAI | General, Long Context | Included • Quality | Included |
| Mistral Large | Mistral AI | Detailed, Precise | Included • Quality | Included |
| Kimi K2 | Moonshot | Balanced, Multilingual | Included • Quality | Included |
| Mistral Small 4 | Mistral AI | Fast, Budget | Included • Speed | Included |
| Qwen 3.5 Flash | Alibaba | Budget, Logical | Included • Reasoning | Included |
| Qwen 3 VL | Alibaba | Vision, Image-aware | Included • Vision | Included |
| DeepSeek V3.2 | DeepSeek | General, Budget | Included • Quality | Included |
| DeepSeek Chat V3.1 | DeepSeek | Budget, Conversational | Included • Lowest Cost | Included |
| Premium Models (BYOK) | ||||
| Kimi K2.5 | Moonshot | Reasoning, Native | Premium • Quality | ~$6.42 |
| GPT-5.4 Mini | OpenAI | Efficient, Capable | Premium • Quality | ~$11.70 |
| Claude Haiku 4.5 | Anthropic | Casual, Playful | Premium • Speed | ~$14.40 |
| Gemini 2.5 Pro | Deep reasoning, Complex | Premium • Reasoning | ~$22.50 | |
| GPT-5 | OpenAI | Instruction Following | Premium • Quality | ~$22.50 |
| GPT-4.1 | OpenAI | Reliable, Long Context | Premium • Quality | ~$26.40 |
| GPT-4o | OpenAI | Familiar, Reliable | Premium • Quality | ~$33.00 |
| GPT-5.4 | OpenAI | High Quality, Creative | Premium • Quality | ~$39.00 |
| Claude Sonnet 4.6 | Anthropic | Expressive, Emotion | Premium • Quality | ~$43.20 |
| Grok 4 | xAI | Powerful, Creative | Premium • Quality | ~$43.20 |
| Claude Opus 4.6 | Anthropic | Maximum Depth | Premium • Reasoning | ~$72.00 |
* Monthly estimates based on 20 messages/day. Actual costs vary by conversation length. Included models carry no extra cost.
A Note on Speed: "Flash" ≠ Always Fastest
Some models with "Flash" in the name (like Alibaba Qwen 3.5 Flash) are actually reasoning models that "think" internally before responding. This hidden reasoning step can make them slower than their non-flash counterparts, even though they cost less per token.
Similarly, premium reasoning models like Google Gemini 2.5 Pro will naturally have longer response times because they're doing deeper analysis — this is by design and produces higher quality responses, but it means they're not ideal if you want instant replies.
If speed is your priority: Grok Fast, Claude Haiku, and Mistral models deliver the snappiest responses. If cost is your priority: the Qwen models are hard to beat — they are fully included for all users.
Tips
- Experiment freely. You can switch models at any time without losing memories, goals, or conversation history. Everything is preserved.
- Different models suit different personas. A companion with a poetic, emotionally complex personality may shine on Claude Sonnet, while a witty, factual companion might be better on Grok or Gemini.
- Premium models fall back gracefully. If your BYOK credits run out, the system automatically falls back to an included model so you never lose access. See our BYOK guide for details.