8 specialized LLM architecture types, each optimized for different agent tasks. Useful when choosing the right model class for a feature.
Note: Model names in this guide reflect the landscape as of mid-2026. Specific models evolve quickly — use this as a framework, not a definitive model list.
The 8 Architecture Types
| Architecture | Best For | Representative Models | When to Use |
|---|---|---|---|
| VLM (Vision-Language) | Multimodal — vision + text | GPT-5, Gemini 3.5 Pro, Claude Opus 4.7 | Image analysis, document processing, visual reasoning |
| LRM (Large Reasoning) | Deep problem-solving | OpenAI o3, Claude Opus (extended thinking), Gemini 3.5 Pro (Deep Think) | Math, coding challenges, strategic planning |
| SLM (Small Language) | Fast, efficient, cheap | Phi-4, Gemma 3, Qwen 3, Claude Haiku 4.5 | Edge devices, real-time apps, cost-sensitive uses |
| LCM (Large Context) | Processing massive text | Gemini 3.5 Pro (2M), Claude Opus/Sonnet 4.x (1M) | Document analysis, long conversations, research |
| HLM (Hierarchical) | Complex multi-step planning | Custom implementations | Project management, workflow automation |
| DLM (Domain Language) | Specialized expertise | Med-PaLM (medical), BloombergGPT (finance) | Industry-specific tasks requiring accuracy |
| ALM (Action Language) | Tool use + real-world actions | Tool-augmented Claude/GPT/Gemini, MCP-based agents | Web scraping, API calls, external integrations |
| RLM (Retrieval Language) | Fact-based responses with sources | Perplexity Pro, RAG systems | Research, fact-checking, cited information |
Gemini Feature Overview
Gemini is Google's multimodal AI family. Key strengths: massive context windows (up to 2M tokens on 3.5 Pro), strong multimodality, tight integration with Google tools (Search, Workspace).
Deep Think Mode
- Adaptive reasoning (similar to OpenAI o3 / Claude extended thinking)
- Iterates internally before outputting
- Uses chain-of-thought + self-verification
- Lower hallucination rates on complex problems
- Best for: coding, research, strategic analysis
Deep Research
- Plans research by outlining steps first
- Retrieves and synthesizes across sources
- Delivers detailed cited reports
- Maintains consistency across long sessions
Canvas
- Collaborative workspace for interactive content
- Build docs, code apps, infographics together
- Turns research into quizzes, web pages, games
- Integrates with Deep Research
Cost Comparison: API Providers (as of mid-2026)
Prices change frequently — verify before building.
| Provider | Model | Input / 1M tokens | Output / 1M tokens | Best For |
|---|---|---|---|---|
| Groq | Llama 3.3 70B | ~$0.59 | ~$0.79 | Lightning-fast inference |
| Together AI | Llama 3.1 405B | ~$3.50 | ~$4.00 | High-quality at scale |
| Gemini 3.5 Flash | low (sub-$1) | low (sub-$1) | Multimodal tasks, generous free tier | |
| Gemini 2.5 Pro (≤200k ctx) | $1.25 | $10.00 | Long-context, top-tier reasoning | |
| xAI | Grok 4.3 | $1.25 | $2.50 | Reasoning + real-time data via X |
| Anthropic | Claude Haiku 4.5 | low | low | Fast, quality responses |
| Anthropic | Claude Sonnet 4.6 (1M ctx) | mid | mid | Coding, long-context analysis |
Pro tip: Route requests — start with cheap/fast (Gemini Flash, Haiku), escalate to a stronger model only if confidence is low or the task is complex.
AI Model Selection by Use Case
| Use Case | Recommended | Cost | Speed |
|---|---|---|---|
| Simple chatbot | Gemini 3.5 Flash, Claude Haiku 4.5 | Low | Fast |
| Complex reasoning | GPT-5, Claude Opus 4.7, Gemini 3.5 Pro (Deep Think) | High | Medium |
| Code generation | Claude Sonnet 4.6, GPT-5, Gemini 3.5 Pro | High | Medium |
| Image analysis | GPT-5, Gemini 3.5 Pro, Claude Opus 4.7 | Medium | Medium |
| Long documents | Claude Sonnet/Opus 4.x (1M), Gemini 2.5/3.5 Pro (1–2M) | High | Slow |
| Real-time chat | Groq Llama, Gemini 3.5 Flash | Low | Very Fast |
| Research tasks | Perplexity, Grok 4.3 with X search, Gemini Deep Research | Medium | Medium |
| Creative writing | Claude Opus 4.7, GPT-5 | High | Medium |
Free and Low-Cost Options
Fully free:
- OpenRouter.ai — routes to free models (Llama variants)
- Hugging Face Inference API — free tier for many models
- Google Gemini Flash — generous free tier
- DeepSeek API — often free/unlimited
Self-hosted:
- Platforms: RunPod, Vast.ai ($0.20–0.50/hr GPU)
- VPS: Hetzner, DigitalOcean GPU ($50–150/month)
- Models: Llama 3.3 8B/70B, Qwen 3, Phi-4, Gemma 3
- Tools: Ollama, vLLM, LocalAI, TGI
- Example: 70B model on $100/month server → ~$0.001/query
Quick start:
- Prototyping → OpenRouter free model
- Production/low cost → Self-host Llama 3.3 8B via Ollama
- Managed → Gemini 3.5 Flash or Claude Haiku 4.5