GPT-5.6 Luna or Gemini 4 Argon?
Choose GPT-5.6 Luna when high-volume extraction, classification and routine agent tasks is the closer match. Choose Gemini 4 Argon when multi-agent systems, deep technical research and multimodal repository analysis matters more. Test both on the same real tasks before moving a production workflow.
High-volume extraction, classification and routine agent tasks
Multi-agent systems, deep technical research and multimodal repository analysis
GPT-5.6 Luna
GPT-5.6 model optimized for cost-sensitive, high-volume workloads.
Official specification ↗Gemini 4 Argon
Google DeepMind's flagship model for persistent multi-agent orchestration and sustained reasoning.
Official specification ↗Side-by-side comparison
| Category | GPT-5.6 Luna | Gemini 4 Argon |
|---|---|---|
| Provider | OpenAI | |
| Type | Model · Reasoning model | Model · Multimodal frontier model |
| Pricing summary | $0.20 input, $0.02 cached input and $1.20 output per 1M tokens | $4 input, $0.40 cached input and $18 output per 1M tokens |
| Input price | $0.20 / 1M tokens | $4 / 1M tokens |
| Cached input | $0.02 / 1M tokens | $0.40 / 1M tokens |
| Output price | $1.20 / 1M tokens | $18 / 1M tokens |
| Context window | 1.05M tokens | 2M tokens |
| Maximum output | 128K tokens | 128K tokens |
| Knowledge cutoff | February 16, 2026 | September 2026 |
| Reasoning | none, low, medium, high, xhigh, max | Integrated chain-of-thought with execution verification |
| Relative speed | Fast / cost optimized | High throughput |
| Input modalities | Text and image | Text, image, audio and video |
| Output modalities | Text | Text and code |
| Tools and integrations | Functions, web search, file search, computer use and supported Responses API tools | Google AI Studio function calling, code execution, web grounding and agent sandboxes |
| API / access | v1/responses, v1/chat/completions and v1/batch | Gemini API v1beta & Vertex AI |
| Best fit | High-volume extraction, classification and routine agent tasks | Multi-agent systems, deep technical research and multimodal repository analysis |
| Company | OpenAI | |
| Product category | Model · Reasoning model | Model · Multimodal frontier model |
| Current pricing note | $0.20 input, $0.02 cached input and $1.20 output per 1M tokens | $4 input, $0.40 cached input and $18 output per 1M tokens |
| Best suited to | High-volume extraction, classification and routine agent tasks | Multi-agent systems, deep technical research and multimodal repository analysis |
| Key capabilities | 1.05M context; 128K maximum output; Vision input; Responses API tools | 2M native multimodal context; Native sandbox code execution; Persistent workspace sessions; Agent orchestration |
| Last verified | 2026-09-08 | 2026-10-15 |
| Official product source | https://developers.openai.com/api/docs/models/gpt-5.6-luna | https://ai.google.dev/gemini-api/docs/models/gemini-4-argon |
How we reached this verdict
We looked at the things that affect everyday use: what each product can do, how its plans are structured, where it fits into your existing workflow, and what the provider currently documents. Benchmark results are useful context, but they are not a universal winner score because test settings and tools vary.
Common questions
GPT-5.6 Luna or Gemini 4 Argon: which should I choose?
Choose GPT-5.6 Luna for high-volume extraction, classification and routine agent tasks. Choose Gemini 4 Argon for multi-agent systems, deep technical research and multimodal repository analysis. Validate the decision with your own prompts and total task cost.
Is GPT-5.6 Luna cheaper than Gemini 4 Argon?
Pricing units can differ. GPT-5.6 Luna: $0.20 input, $0.02 cached input and $1.20 output per 1M tokens. Gemini 4 Argon: $4 input, $0.40 cached input and $18 output per 1M tokens. Check tool charges, plan limits, caching and long-context rules before comparing totals.
Which is better for coding and agent work?
Capability depends on the selected product surface, tools and harness. GPT-5.6 Luna is positioned for high-volume extraction, classification and routine agent tasks; Gemini 4 Argon is positioned for multi-agent systems, deep technical research and multimodal repository analysis. Run the same repository task on both.
How do their context windows compare?
GPT-5.6 Luna lists 1.05M tokens; Gemini 4 Argon lists 2M tokens. A larger limit does not by itself guarantee better retrieval or lower cost.
Official sources
Use these provider pages to confirm current features, pricing and availability.
AI tools change quickly. We checked this page on 2026-09-08. Before you subscribe, confirm the latest price, regional availability and usage limits on the provider website.