IFStruct
Models generate JSON or YAML that must follow a requested schema and phrasing constraints, without constrained decoding. A response passes only if every structural constraint holds.
2,000 frozen test prompts. The makers say it saturates near 100% for frontier models and targets small models.
- Made by
- Liquid AI
- Released
- June 2026
- Kind
- Following precise instructions
- Level
- Everyday
- Scored
- Checked automatically
- Answers
- Open-ended
- Tasks
- All public
- Strongest model tested
-
Gemma 4 31B IT #100 on the capability index
- Last in a launch post
- October 2026
- Last model added
- October 2026
- Scores refreshed
- November 12th, 2026
Gemma 4 31B IT leads with 95.9% among models released by April 2026
Best score per entry from the benchmark's own leaderboard, read on November 12th, 2026. Where a model ran with several settings or harnesses, we keep its best. Names in gray aren't in our model list: fine-tunes, agent systems, products and older models. They don't count toward leaders.
Gemma 4 31B IT leads with 95.9%, claims included
Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.
The newest model with a score here came out in April 2026, and nobody has tested a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:
- Claude Fable 5.2
-
Gemini 4 Carbon
- GPT-6 Astra
- Claude Opus 5.5
- and 16 more
- 95.9
Gemma 4 31B IT
- 92.0 gpt-oss-20b
- 86.8
Nemotron 3 Nano 30B-A3B
- 79.8
Qwen3-8B
- 76.7
Gemma 4 E4B
- 68.5 Granite 4.1 8B
- 64.8
Gemma 4 E2B
- 44.9 LFM2.5-350M + IFStruct RL
- 38.8 granite-4.0-h-tiny
- 36.3
Qwen3.5-4B
- 33.1
Qwen3.5-2B
- 21.1 LFM2.5-350M
- 15.5
Qwen3.5-0.8B
- 1.70 granite-4.0-h-350m
- 0.50 gemma-3-270m-it
- 1
Gemma 4 31B IT 95.9%
- 2 gpt-oss-20b 92%
- 3
Nemotron 3 Nano 30B-A3B 86.8%
- 4
Qwen3-8B 79.8%
- 5
Gemma 4 E4B 76.7%
- 6 Granite 4.1 8B 68.5%
- 7
Gemma 4 E2B 64.8%
- 8 LFM2.5-350M + IFStruct RL 44.9%
- 9 granite-4.0-h-tiny 38.8%
- 10
Qwen3.5-4B 36.3%
- 11
Qwen3.5-2B 33.1%
- 12 LFM2.5-350M 21.1%
- 13
Qwen3.5-0.8B 15.5%
- 14 granite-4.0-h-350m 1.70%
- 15 gemma-3-270m-it 0.50%
Source: Official IFStruct leaderboard
- 1
Gemma 4 31B IT 95.9%
- 2 LFM3-1.7B 93.7%
- 3 gpt-oss-20b 92%
- 4
Nemotron 3 Nano 30B-A3B 86.8%
- 5 LFM2.5-2.6B 85.5%
- 6
Qwen3-8B 79.8%
- 7
Gemma 4 E4B 76.7%
- 8 Granite 4.1 8B 68.5%
- 9
Gemma 4 E2B 64.8%
- 10
Qwen3.5-4B 36.3%
- 11
Qwen3.5-2B 33.1%
- 12
Qwen3.5-0.8B 15.5%
Sources: Official IFStruct leaderboard and labs’ model cards
| # | Entry | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 95.9% | Apr 2026 | Official leaderboard | |
| 2 | gpt-oss-20b | 92% | Aug 2025 | Official leaderboard | |
| 3 | | 86.8% | Dec 2025 | Official leaderboard | |
| 4 | | 79.8% | Apr 2025 | Official leaderboard | |
| 5 | | 76.7% | Mar 2026 | Official leaderboard | |
| 6 | Granite 4.1 8B | 68.5% | Apr 2026 | Official leaderboard | |
| 7 | | 64.8% | Mar 2026 | Official leaderboard | |
| 8 | LFM2.5-350M + IFStruct RL | 44.9% | Official leaderboard | ||
| 9 | granite-4.0-h-tiny | 38.8% | Official leaderboard | ||
| 10 | | 36.3% | Feb 2026 | Official leaderboard | |
| 11 | | 33.1% | Feb 2026 | Official leaderboard | |
| 12 | LFM2.5-350M | 21.1% | Official leaderboard | ||
| 13 | | 15.5% | Feb 2026 | Official leaderboard | |
| 14 | granite-4.0-h-350m | 1.70% | Official leaderboard | ||
| 15 | gemma-3-270m-it | 0.50% | Official leaderboard |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 95.9% | Apr 2026 | Official leaderboard | |
| 2 | LFM3-1.7B | 93.7% | Oct 2026 | Lab model card | |
| 3 | gpt-oss-20b | 92% | Aug 2025 | Official leaderboard | |
| 4 | | 86.8% | Dec 2025 | Official leaderboard | |
| 5 | LFM2.5-2.6B | 85.5% | Aug 2026 | Lab model card | |
| 6 | | 79.8% | Apr 2025 | Official leaderboard | |
| 7 | | 76.7% | Mar 2026 | Official leaderboard | |
| 8 | Granite 4.1 8B | 68.5% | Apr 2026 | Official leaderboard | |
| 9 | | 64.8% | Mar 2026 | Official leaderboard | |
| 10 | | 36.3% | Feb 2026 | Official leaderboard | |
| 11 | | 33.1% | Feb 2026 | Official leaderboard | |
| 12 | | 15.5% | Feb 2026 | Official leaderboard |
Labs report scores for 2 models in their cards. Switch the scores above to rank them together.
Number one over time Number one over time
Lab claims count from the day the card came out, independent runs from the model’s release.
Source: Official IFStruct leaderboard
Gpt-oss-20b on the official leaderboard passed 85% in August 2025
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Sources: Official IFStruct leaderboard and labs’ model cards
One lab put it in a launch post in the last six months
Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.
| Date | Launch post | Score | As the post writes it |
|---|---|---|---|
| Oct 27, 2026 | LFM3-1.7B | 93.7 | IFStruct |
| Aug 4, 2026 | LFM2.5-2.6B | 85.5 | IFStruct |
More in Instructions and chat
- IFEval In use Models answer about 500 prompts containing verifiable instructions such as word limits or required keywords. Code checks each instruction for strict and loose accuracy.
Gemma 4 31B IT 98.9%
- IFBench In use 58 new out-of-domain verifiable output constraints. Scored by programmatic constraint checks (strict or loose).
Nemotron-Cascade 2 30B-A3B 82.9%
- MultiChallenge In use Multi-turn conversations testing instruction retention, inference memory, versioned editing and self-coherence. Graded by LLM judge with rubrics. GPT-6.1 Sol 82%
- Multi-IF In use Models follow verifiable instructions over three-turn conversations in eight languages, extending IFEval. Scored by instruction accuracy at each turn. LFM3-1.7B 89.1%
- AdvancedIF In use Models respond to over 1,600 prompts with complex, multi-turn, and system-level instructions. A judge model checks each response against expert-written rubrics.
MAI-Thinking-1 85%
- HANDBOOK.md In use Agents do routine company work with mock email, chat, calendar, issue and commerce tools while following a 20 to 124 page handbook. Programmatic criteria check required and forbidden actions, and a trial passes only if all pass. Claude Opus 5.5 52.3%