Model comparison
Compare GPT-5.6 Luna and Grok 4.20 Multi-Agent Beta using the same provider-sourced text & reasoning rubric. No mystery score and no invented benchmark ranking.
Facts checked September 14, 2026
Set your usage. Your estimate updates as you type.
Example: 6,000 input tokens for 10 pages, plus a 500-token summary. Page lengths vary; adjust the numbers below.
One run sends your input to the model once and receives an answer. Tokens are pieces of text: input is what you send, output is the answer you receive.
Estimates exclude taxes, tools, cache storage/writes, free allowances and custom discounts. Image estimates cover output only, not prompt or reference-image charges. Quality modes differ by model. Unlisted settings are not treated as free.
| Model | Access | Estimated total (USD) |
|---|---|---|
| GPT-5.6 LunaOpenAI | OpenAI | $0.0018 |
| Grok 4.20 Multi-Agent BetaSpaceXAI | SpaceXAI | No reviewed rate |
Quick take
The budget GPT-5.6 tier for processing many short, repeatable tasks.
Low token prices do not guarantee a low task cost if the model needs retries or extensive reasoning.
A specialist Grok model that sends several AI agents to investigate a difficult question in parallel, then combines their work into one researched answer.
This is a beta product, not the newest general-purpose Grok. Its interface may change, and built-in searches or code runs can add cost beyond the headline token price.
Compare the published facts
Values use each provider's own published units and limits. A blank means the provider did not publish a directly comparable value in the sources reviewed.
| Text & reasoning | GPT-5.6 Luna | Grok 4.20 Multi-Agent Beta |
|---|---|---|
| Context windowMaximum combined prompt and working context documented by the provider. | 1.05M tokens | 1,000,000 tokens |
| Maximum outputProvider-published response limit, where available. | 128K tokens | Not published |
| Knowledge cutoffLatest reliable knowledge date explicitly published by the model provider. Search and connected tools can retrieve newer information but do not change the model's built-in cutoff. | February 16, 2026 | Not published |
| Input priceCurrent standard list price per million input tokens unless noted. | $0.2 / 1M | $1.25 / 1M |
| Output priceCurrent standard list price per million output tokens unless noted. | $1.2 / 1M | $2.50 / 1M |
| InputsMedia types accepted by the listed model endpoint. | Text, image | Text, image |
| Tools & agentsSelected native tools and agent-building capabilities, not an exhaustive list. | Functions, web/file search, code, computer, MCP | 4–16 agents; functions, web/X, code, collections |
How to choose
Start with the job you need to complete, then validate cost, access, and policy details on your exact provider route.
OpenAI says API inputs and outputs are not used for model training by default. Default abuse-monitoring logs may be retained for up to 30 days; qualifying organizations can request other controls.
Provider and API links
SpaceXAI says API inputs and outputs are not used for training without explicit permission. Requests are encrypted and retained for 30 days by default; team-level zero data retention is available with feature tradeoffs.
Provider and API links
Frequently asked questions
GPT-5.6 Luna: The budget GPT-5.6 tier for processing many short, repeatable tasks. Grok 4.20 Multi-Agent Beta: A specialist Grok model that sends several AI agents to investigate a difficult question in parallel, then combines their work into one researched answer.
Consider GPT-5.6 Luna when your priority is Data extraction. Consider Grok 4.20 Multi-Agent Beta when your priority is Deep research with several lines of inquiry. Test both with your own data and provider route before committing.
No. This comparison aligns provider-published facts for the Text & reasoning category. It does not claim a universal winner or combine incompatible third-party benchmark scores.
