ARC Prize 2026 Milestone #2: open-source ARC-AGI-3 agents top out at 27.9% under Kaggle compute limits

2026-10-01★★after cutoffbenchmarkARC Prize FoundationTufa Labsconfidence: high

On Oct 1, 2026 ARC Prize announced the Milestone #2 winners of its ARC-AGI-3 Kaggle competition, all of whom open-sourced their agents: Daniel Franzen (27.9%, $25K), "Lord Han Solo" (23.8%, $7.5K) and Lohit Siriki (22.5%, $5K). The open, compute-limited track remains far behind frontier models with provider harnesses (GPT-6 Astra 99.9%, GPT-6.1 Sol 96.4%). Tufa Labs leads the live Kaggle leaderboard with 45.33% (Sept 29), and several winning entries build on its open "Duck" harness.

Key facts

Milestone #2 (deadline Sept 30, 2026) winners, announced Oct 1: 1. Daniel Franzen 27.9% ($25K); 2. Lord Han Solo 23.8% ($7.5K); 3. Lohit Siriki 22.5% ($5K)
The prize split announced differs from the schedule on the competition page ($25K / $10K / $2.5K); ARC Prize gave no reason
Only participants who open-source their solutions by the deadline are eligible for milestone prizes; the 2nd- and 3rd-place notebooks are titled as built on Tufa Labs' 'Duck' harness
Live Kaggle leaderboard: Tufa Labs retook 1st place with 45.33% (up from 27.29%) on Sept 29 (scored on part of the test data)
Milestone #1 (June 30) went to Tufa Labs ('The Duck': a small open LLM writing and running Python in a REPL), Reki (Gemma-4-31B as a vision policy) and Md Boktiar Mahbub Murad
Remaining dates: entry deadline Oct 26, final submissions Nov 2, results Dec 4, 2026

What happened

ARC Prize's Kaggle competition for ARC-AGI-3, its interactive-game reasoning benchmark, gives interim prizes to open-sourced solutions. On Oct 1, 2026 ARC Prize named the Milestone #2 winners. Daniel Franzen scored 27.9% (a Daniel Franzen was also part of "The ARChitects", the ARC Prize 2024 winners; ARC Prize did not say whether this is the same person), Kaggle user "Lord Han Solo" 23.8% and Lohit Siriki 22.5%. All three published their notebooks on Kaggle. Two of the notebooks say they build on Tufa Labs' "Duck" harness, which won Milestone #1. Tufa Labs itself leads the live leaderboard at 45.33% (Sept 29), but it is not among the Milestone #2 prize winners.

Why it matters

The Kaggle track runs open models under Kaggle's compute limits, so it measures how far open methods get without frontier APIs. In the same week, ARC Prize verified frontier API models with provider harnesses near the ceiling: GPT-6 Astra at 99.9% and GPT-6.1 Sol at 96.4%. Open agents under Kaggle's limits are at roughly 22–45%. That gap is the main open question before the final results on Dec 4.

Changelog

2026-10-04: created (outcome of upcoming item 2026-09-30-arc-prize-2026-milestone-2)

Related events

2026-03-25ARC Prize launches ARC-AGI-3, an interactive game benchmark where frontier AI scored under 1% ★★★★
2026-09-03GPT-6 Astra scores 62.7% on ARC-AGI-3 (99.9% with provider harness), outacting humans on 96% of levels ★★★★★
2026-09-29OpenAI releases GPT-6.1 Sol: near-Astra performance at one-fifth of Astra's price ★★★★

Sources (8)

id: 2026-10-01-arc-prize-2026-milestone-2-winners · updated 2026-10-04 · open in the interactive timeline