● THE COGNITION ANNALS · node 07 · uplink secure · channel: DOGBED · knap → k4o → textile → oliver → html

INDEX COGNITION DEVIN WINDSURF PRODUCTS SWE-1 SWE-1.5 SWE-1.6 SWE-1.7 SWE-2 TIMELINE LEDGER COMMITS

transmission 07 · model wing, hall iii

SWE-1.6: MODEL UX

Spring 2026. The training runs got two orders of magnitude more compute, and Cognition spent the surplus on something unusual: manners. SWE-1.6 was post-trained to jointly optimize intelligence and ‘model UX’ — how the model feels to work with, not just what it scores.

THE PREVIEW

Cognition broke its own tradition and published mid-run results. The SWE-1.6 Preview checkpoint — post-trained from the same base as SWE-1.5 — was already *+11% on SWE-Bench Pro* over its predecessor while running at the same 950 tok/s. The stated reason for the peek: get real users on the checkpoint early and tune behavior with feedback, not vibes.

The eval table in that post is a time capsule of the frontier in early 2026: Claude Opus 4.6 and Sonnet 4.6, GPT-5.3-Codex and Codex-Spark, GLM-5, Kimi K2.5, Composer-1.5 — every model run through the same three harnesses (Claude Code, Cascade, Devin) where vendors hadn’t reported numbers.

GENERALLY AVAILABLE

April 2026: SWE-1.6 shipped to everyone in Windsurf with a pricing stunt — free for three months. Two serving paths:

• Fireworks — the free tier at ~200 tok/s.
• Cerebras — the paid tier at 950 tok/s, sold as SWE-1.6 Fast: same intelligence, unmatched speed.

WHAT ‘MODEL UX’ MEANT

• Smoother turn-taking — fewer stalls, fewer degenerate loops, better pacing on long tasks.
• Trained for the agent experience end-to-end rather than benchmark-pinned.
• A signal that the frontier was moving past raw score: SWE-Bench Pro had already displaced SWE-Bench as the eval that mattered — harder, less contaminated, longer-horizon.

SWE-1.6 is optimized for both intelligence and model UX — trained to make the model feel smoother to use, in addition to raw intelligence. — Cognition, April 2026

THE LEDGER

Next hall: the model moves inside the agent harness itself — SWE-1.7.

— END OF TRANSMISSION · CTR-(ok)VERIFIED% —

INDEX COGNITION DEVIN WINDSURF PRODUCTS SWE-1 SWE-1.5 SWE-1.6 SWE-1.7 SWE-2 TIMELINE LEDGER COMMITS

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