SHELFCRITTER AI Digest

MODEL

GPT-6.1 Sol

modeltopic-noteopenai

Overview

GPT-6.1 Sol is OpenAI‘s Sept 29, 2026 DevDay 2026 cost-optimised frontier model — positioned as “near-Astra intelligence for a fifth of the price”. Standard pricing lands at $2 / $10 per Mtok input/output with $0.10/Mtok cached input and a long-context (>272K tokens) surcharge of $4 / $15. The price ratio is exactly 1/5 of Astra’s $10 / $50 standard tier and $1/Mtok cache on both sides — arithmetically clean, not “~1/5” rounding. Ships in ChatGPT Work and Codex for Plus / Pro / Business / Enterprise / Edu tiers and the API on release day; explicitly not yet in standard Chat.

Timeline

  • 2026-09-30-AI-Digest — Sept 29 DevDay 2026 launch as the anchor pricing datum of the day’s product bundle. $2 / $10 per Mtok in/out, $0.10/Mtok cached input, $4 / $15 above the 272K-token boundary — exactly 1/5 of Astra on standard and cache-input tiers alike. HN thread “GPT 6.1 Sol: Near-Astra intelligence for a fifth of the price” (846 pts / 771 cmts) is the day’s largest AI discussion. Available in ChatGPT Work / Codex for Plus / Pro / Business / Enterprise / Edu and via the API; not in standard Chat. Load-bearing reframe: Sol 6.1 is OpenAI's Astra-quality-at-1/5-price positioning, mirroring the Sonnet-5.5-vs-Opus-5.5 compression Anthropic shipped last week — the mid-tier collapse is now an industry-wide pattern, not an Anthropic distinctive. The Aider polyglot top-5 still hadn’t rotated to include Sol 6.1 as of the Sept 30 fetch; measurement lag on the compressed-tier axis stretches into a second week.

Key Developments

  1. Exactly 1/5 of Astra Pricing at Standard and Cached-Input Tiers (September 29, 2026): $2 / $10 per Mtok input/output vs Astra’s $10 / $50; $0.10 cached input vs Astra’s $1. The ratio lands clean on both sides — the corpus should carry “exactly 1/5” rather than “~1/5” rounding. Long-context (>272K) surcharge of $4 / $15 vs Astra’s $20 / $75 also lands at 1/5 on the input tier. Covered in 2026-09-30-AI-Digest.

  2. Anchor Datum of the DevDay 2026 Repricing Bundle (September 29, 2026): Sol 6.1 is the frontier-tier compression anchor around which Dots, Ultrafast, and the Pro 100 / Pro 200 / Pro 500 reshuffle are structured. The load-bearing reframe: today’s slate is a bundled tier-repricing, not a set of unrelated launches. Covered in 2026-09-30-AI-Digest.

  3. Ships in ChatGPT Work + Codex + API on Release Day; Not in Standard Chat (September 29, 2026): The rollout matches the Sol / Luna split established by GPT-6 Sol and GPT-6 Luna — Sol carries the reasoning premium into paid work surfaces, while Chat continues on prior-generation defaults. Practitioner-visible via Codex on day one. Covered in 2026-09-30-AI-Digest.

  • 2026-10-01-AI-Digest — GPT-6.1 Sol ($2/$10, Sept 29) is now one of four frontier labs on the convergent mid-tier line as Google ships Gemini 4 Argon at $2/$10 introductory the same per-token line. Four frontier labs inside a single quarter — Grok 4.7 ($2/$6, Sep 21), Claude Sonnet 5.5 ($2/$10, Sep 28), GPT-6.1 Sol ($2/$10, Sep 29), and Gemini 4 Argon ($2/$10 intro, Oct 1). Framing to carry: convergent competitive repricing, not coordination — the Astra-at-$10/$50-vs-mid-tier-at-$2/$10 gap holds at ~5× across all four labs; Argon’s post-introductory $4/$20 standard rate is the first visible signal the floor may not hold through 2027. GPT-6.1 Sol at exactly 1/5 of Astra on both standard and cached-input tiers remains the arithmetically-cleanest instance of the mid-tier compression — the other three labs are directionally identical but less exact.

See also: OpenAI, GPT-6 Sol, Astra, Dots, Claude Sonnet 5.5, Gemini 4 Argon, MOC - Major Companies, MOC - Agentic Coding.