> Imported exploration, 2026-09-13. Source claims have not been independently verified by this repository. See [integration review](../docs/integration-review.md).

# Artificial capability frontier — snapshot 13 September 2026

This is a **dated reading**, assembled from public leaderboards and lab announcements. Independent aggregators disagree. Treat ranks as a cloud, not a podium.

## What “frontier” means here

A model is **frontier-class** if it is inside the current top cluster on at least one of: Artificial Analysis Intelligence Index (current version), Epoch ECI, a hard agentic coding/computer-use board, or a hard science/math board — *and* it is a product someone can actually call or download.

Peak-score models that are invitation-only or unreleased (e.g. some Mythos-class preview lanes) are **frontier-adjacent**, not generally usable Frontier.

## Cluster as of this week

Rough usable cluster (not a single official ranking):

| Role this week | Model | Lab | Notes |
| --- | --- | --- | --- |
| Joint intelligence-index lead (AA v4.3, max effort) | Claude Fable 5.1 and GPT-6 Astra | Anthropic / OpenAI | Tied at 53 on AA Intelligence Index v4.3 after the 4–7 Sep rebase |
| Strong general / coding workhorse at mid price | Claude Opus 5 | Anthropic | Same $5/$25 list as older Opus; SWE-bench Verified ~96, Pro ~79.2 (lab-reported) |
| Previous OpenAI flagship still widely deployed | GPT-5.6 Sol / Terra / Luna | OpenAI | Sol remains a reference; Terra often the efficiency pick inside the family |
| Cheap multimodal workhorse | Gemini 3.8 Flash | Google | GA 2 Sep; Gemini 3.5 Pro still not generally shipped |
| Real-time / long-horizon value hosted model | Grok 4.6 | xAI | Current xAI flagship; Grok 4.7 rumored, not shipped as of 13 Sep |
| Closed Meta line | Muse Spark 1.3 | Meta Superintelligence Labs | Low list price vs US lab peers on some boards |
| Leading open / exportable cluster | Kimi K3, Qwen3.8-Max, DeepSeek V4.x (V4-Pro and V4.1 Flash), GLM-5.3 | Moonshot, Alibaba, DeepSeek, Z.ai | Open or semi-open paths; distillation and export-control fights are political facts |

**Headline capability claims to verify, not swallow:** GPT-6 Astra’s ARC-AGI-3 number is wrapper-sensitive (public reports of ~63% on ARC Prize harness vs 99.9% on a provider adapter). That gap is itself an Intelligence Radar finding: **the harness is part of the model.**

## Economics and availability (the other half of the frontier)

- **Price span** among near-frontier models is two orders of magnitude on blended $/M tokens and still large on *cost per completed hard task*.
- **Token cost ≠ task cost.** Reasoning models that emit fewer hidden tokens can beat a cheaper list price.
- **Capacity is a constraint.** Mid-September reporting: OpenAI paused some $200 ChatGPT Pro signups/upgrades amid Astra demand. A sold-out Frontier is not an available Frontier.
- **Access tiers matter:** Fable 5.1 general vs Mythos 5.1 restricted; Astra first to cybersecurity “Daybreak” customers then broader; some Chinese weights are legally or practically unavailable in parts of the West.
- **Hardware sovereignty** is now a first-class story (DeepSeek training paths on non-NVIDIA stacks; EU/US compute buildout; export controls).

Detailed prices live in `../frontier/ledger-2026-09.md` and will drift. Re-check before any buying decision.

## What moved this month (for the weekly series)

- 1 Sep — Claude Fable 5.1 / Mythos 5.1
- 2 Sep — Gemini 3.8 Flash; Muse Spark 1.3
- 3 Sep — GPT-6 Astra
- 4–7 Sep — Artificial Analysis Index v4.2 then v4.3 rebase (harder terminal bench + AutomationBench-AA)
- 10 Sep — DeepSeek V4.1 Flash; Cognition SWE-2 (near-frontier coding at lower cost)
- Ongoing — Grok 4.7 slip; Gemini 3.5 Pro still unshipped; policy noise in Washington and Beijing

## Changelog

- 2026-09-13: v0.1 snapshot.