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GPT-5.6 Luna vs gpt oss safeguard 120b

GPT-5.6 Luna (OpenAI) and gpt oss safeguard 120b (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 12 September 2026

As of 12 September 2026, GPT-5.6 Luna holds the stronger ModelCap Index position (#27 vs #143); and gpt oss safeguard 120b ships open weights.

Which should you choose?

Choose GPT-5.6 Luna if…

  • you want the stronger overall ModelCap Index position — #27 against #143 (70.1 vs 32.3 points).
  • you want provider choice — 3 listed API providers against 0.
  • you want the more recently listed model — GPT-5.6 Luna was listed 9 July 2026, gpt oss safeguard 120b 18 September 2025.

Choose gpt oss safeguard 120b if…

  • you want to self-host: gpt oss safeguard 120b ships open weights while GPT-5.6 Luna is api only.

GPT-5.6 Luna vs gpt oss safeguard 120b: specs, pricing and context

Specification comparison of GPT-5.6 Luna and gpt oss safeguard 120b
FieldGPT-5.6 LunaOpenAIgpt oss safeguard 120bOpenAI
ModelCap Index position#27#143
Index score70.132.3
EvidenceMeasuredInherited
Input price / 1M tokens$0.20Unlisted
Output price / 1M tokens$1.20Unlisted
Context window1M tokens— tokens
Max output tokens128K—
API providers listed30
Weight accessAPI onlyOpen weights
Input modalitiesFile, Image, TextText
First listed9 July 202618 September 2025
PublisherOpenAIOpenAI

Evidence: 6 public benchmark observations across 6 boards · finetune of openai/gpt-oss-120b · fp4 (100%). Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-5.6 Luna vs gpt oss safeguard 120b

Public benchmark boards where GPT-5.6 Luna or gpt oss safeguard 120b has a published result
BoardGPT-5.6 Lunagpt oss safeguard 120bLeads
Arena codingArena (LMArena)14981490–1505X-High—Only one result
LMArena AgentLMArena0.7%-0.3%–1.8%X-High—Only one result
ARC-AGI-2ARC Prize Foundation59.5%Max—Only one result
ARC-AGI-3ARC Prize Foundation0.2%Max—Only one result
AA Intelligence IndexArtificial Analysis37.5intelligence-index:v4.3:max—Only one result
AA Terminal-Bench 2.1Artificial Analysis80.9%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="GPT-5.6 Luna (max)":reasoning=true—Only one result
AA Humanity's Last ExamArtificial Analysis39.5%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.6 Luna (max)":reasoning=true—Only one result
Terminal-Bench 4.0Terminal-Bench (Laude Institute)17.3%14.4%–20.1%Codex · Max—Only one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

GPT-5.6 Luna vs gpt oss safeguard 120b: common questions

Is GPT-5.6 Luna better than gpt oss safeguard 120b?

GPT-5.6 Luna ranks higher on the ModelCap Index as of 12 September 2026: #27 against #143. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is GPT-5.6 Luna cheaper than gpt oss safeguard 120b?

At least one of the two has no listed API price on ModelCap right now, so no price comparison is made.

Which has the bigger context window, GPT-5.6 Luna or gpt oss safeguard 120b?

Both publish a 1M-token context window.

Which is better for coding, GPT-5.6 Luna or gpt oss safeguard 120b?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are GPT-5.6 Luna and gpt oss safeguard 120b open-weight models?

GPT-5.6 Luna: API only. gpt oss safeguard 120b: Open weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run GPT-5.6 Luna and gpt oss safeguard 120b?

ModelCap currently lists 3 API providers for GPT-5.6 Luna and 0 for gpt oss safeguard 120b, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GPT-5.6 Luna vs gpt oss safeguard 120b comparison?

Every figure comes from the sealed ModelCap dataset published 12 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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