NLP Lineage

20 December 2024 · Reasoning

o3 announced

OpenAI o3 announcement

OpenAI

Date
20 December 2024
What the date marks
Announcement
Kind
Model
Organisation
OpenAI
Access
announcement only
Other dates
model released April 2025
Threads
In the guided tour
Chapter 12. Thinking longer
Learning phases
2. How LLMs are trained

A milestone: 1 later milestone descends directly from it, and its descendants reach 5 of the 10 threads. How levels are decided

Read the primary source (arcprize.org)

Full summary in progress. Until then, this page shows the milestone's record from the research data.

What it changed

Before it

o1 had established RL-trained reasoning three months earlier.

The problem

Was the approach a one-off, or does reasoning keep improving with more RL and more inference compute?

What it introduced

Large jumps on ARC-AGI and FrontierMath, at very high inference cost per task.

Why it matters

It showed the reasoning axis had real headroom. Note the scores are OpenAI-reported, ARC-AGI results are on the public eval set, and Epoch AI later disclosed OpenAI funding and data access for FrontierMath.

What modern models inherit

Reasoning capability that scales with inference spend, and the cost question that comes with it.

What came next

Released in April 2025 alongside o4-mini, then folded into GPT-5.

Before and after

The milestones it descends from, and the milestones that descend from it. Work developed alongside it is not counted. Weak links are left out unless you include them.

Before: where it came from

o3 announced has 20 documented ancestors across 6 chapters, reaching back to Recurrent networks in 1990. Showing its direct parents and the 11 turning points among them.

o3 announced has 20 documented ancestors across 6 chapters, reaching back to Recurrent networks in 1990. Showing all of them.

o3 announced has 35 recorded ancestors, including indirect ones, across 7 chapters, reaching back to Recurrent networks in 1990. Showing its direct parents and the 11 turning points among them.

o3 announced has 35 recorded ancestors, including indirect ones, across 7 chapters, reaching back to Recurrent networks in 1990. Showing all of them.

  1. 2024o3 announcedThis milestone.
  2. 2024o1 Turning pointo3 announced built directly on thisChapter 12. Thinking longer
  3. 2022Chain of thought Turning pointo1 was influenced by thisChapter 12. Thinking longer
  4. 2020GPT-3 Turning pointChain of thought was influenced by thisChapter 5. Scale becomes a science
  5. 2020Scaling laws Turning pointGPT-3 was influenced by thisChapter 5. Scale becomes a science
  6. 2019Sparse Transformer Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  7. 2019GPT-2 Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  8. 2019WebTextGPT-2 was influenced by thisChapter 4. Pretrain once, use everywhere
  9. 2018GPT-1GPT-2 built directly on thisChapter 4. Pretrain once, use everywhere
  10. 2017Transformer Turning pointGPT-2 built directly on this
    Sparse Transformer built directly on this
    Scaling laws built directly on this    Chapter 3. Attention, then only attention
  11. 2016Layer normGPT-2 built directly on thisChapter 3. Attention, then only attention
  12. 2015Residual connectionsTransformer was influenced by thisChapter 3. Attention, then only attention
  13. 2015LM pretraining Turning pointGPT-1 was influenced by thisChapter 2. Words become vectors
  14. 2015BPE tokenizationGPT-2 built directly on thisChapter 2. Words become vectors
  15. 2015Luong attentionTransformer was influenced by thisChapter 3. Attention, then only attention
  16. 2014AdamTransformer was influenced by thisChapter 2. Words become vectors
  17. 2014Seq2seq Turning pointTransformer built directly on thisChapter 2. Words become vectors
  18. 2014Attention Turning pointTransformer built directly on thisChapter 3. Attention, then only attention
  19. 2014GRU / encoder-decoderAttention built directly on thisChapter 2. Words become vectors
  20. 1997LSTM Turning pointSeq2seq built directly on thisChapter 1. Language as probability
  21. 1990Recurrent networksLSTM was influenced by thisChapter 1. Language as probability
  1. 2024o3 announcedThis milestone.
  2. 2024o1 Turning pointo3 announced built directly on thisChapter 12. Thinking longer
  3. 2024Test-time computeo3 announced was influenced by this (indirect influence)Chapter 12. Thinking longer
  4. 2023Process supervisionTest-time compute was influenced by this
    o1 was influenced by this (indirect influence)    Chapter 12. Thinking longer
  5. 2023Tree of thoughtsTest-time compute was influenced by this (indirect influence)Chapter 12. Thinking longer
  6. 2022STaRTest-time compute was influenced by this (indirect influence)
    o1 was influenced by this (indirect influence)    Chapter 12. Thinking longer
  7. 2022Self-consistencyTest-time compute built directly on thisChapter 12. Thinking longer
  8. 2022Chain of thought Turning pointo1 was influenced by thisChapter 12. Thinking longer
  9. 2020GPT-3 Turning pointChain of thought was influenced by thisChapter 5. Scale becomes a science
  10. 2020Scaling laws Turning pointGPT-3 was influenced by thisChapter 5. Scale becomes a science
  11. 2019Sparse Transformer Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  12. 2019GPT-2 Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  13. 2019WebTextGPT-2 was influenced by thisChapter 4. Pretrain once, use everywhere
  14. 2019Transformer-XLSparse Transformer was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  15. 2018GPT-1GPT-2 built directly on thisChapter 4. Pretrain once, use everywhere
  16. 2018ELMoGPT-1 was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  17. 2018ULMFiTGPT-1 was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  18. 2017CoVeELMo was influenced by thisChapter 3. Attention, then only attention
  19. 2017RLHF origino1 was influenced by this (indirect influence)Chapter 6. Teaching models what people want
  20. 2017Transformer Turning pointGPT-2 built directly on this
    Sparse Transformer built directly on this
    Scaling laws built directly on this    Chapter 3. Attention, then only attention
  21. 2017ConvS2STransformer was influenced by this (indirect influence)Chapter 3. Attention, then only attention
  22. 2016Layer normGPT-2 built directly on thisChapter 3. Attention, then only attention
  23. 2015Residual connectionsTransformer was influenced by thisChapter 3. Attention, then only attention
  24. 2015LM pretraining Turning pointGPT-1 was influenced by thisChapter 2. Words become vectors
  25. 2015BPE tokenizationGPT-2 built directly on thisChapter 2. Words become vectors
  26. 2015Luong attentionTransformer was influenced by thisChapter 3. Attention, then only attention
  27. 2014AdamTransformer was influenced by thisChapter 2. Words become vectors
  28. 2014GloVeELMo built directly on thisChapter 2. Words become vectors
  29. 2014Seq2seq Turning pointTransformer built directly on thisChapter 2. Words become vectors
  30. 2014Attention Turning pointTransformer built directly on thisChapter 3. Attention, then only attention
  31. 2014GRU / encoder-decoderAttention built directly on thisChapter 2. Words become vectors
  32. 2013word2vecELMo was influenced by thisChapter 2. Words become vectors
  33. 2011NLP from scratchELMo was influenced by thisChapter 1. Language as probability
  34. 2003Neural LMNLP from scratch was influenced by this
    word2vec was influenced by this    Chapter 1. Language as probability
  35. 1997LSTM Turning pointSeq2seq built directly on this
    ELMo built directly on this    Chapter 1. Language as probability
  36. 1990Recurrent networksLSTM was influenced by thisChapter 1. Language as probability

After: what it led to

o3 announced has 10 documented descendants across 4 chapters, reaching forward to GPT-5.6 Sol in 2026. Showing its direct descendants.

o3 announced has 10 documented descendants across 4 chapters, reaching forward to GPT-5.6 Sol in 2026. Showing all of them.

o3 announced has 10 recorded descendants, including indirect ones, across 4 chapters, reaching forward to GPT-5.6 Sol in 2026. Showing its direct descendants.

o3 announced has 10 recorded descendants, including indirect ones, across 4 chapters, reaching forward to GPT-5.6 Sol in 2026. Showing all of them.

  1. 2024o3 announcedThis milestone.
  2. 2025Deep researchwas influenced by o3 releasedChapter 13. Models that act
  3. 2025o3 releasedsucceeded o3 announcedChapter 12. Thinking longer
  4. 2025gpt-ossbuilt directly on o3 releasedChapter 8. The weights get out
  5. 2025GPT-5built directly on o3 releasedChapter 14. Where the threads meet now
  6. 2025GPT-5.1built directly on GPT-5Chapter 14. Where the threads meet now
  7. 2025GPT-5.2built directly on GPT-5.1Chapter 14. Where the threads meet now
  8. 2026GPT-5.3-Codexbuilt directly on GPT-5.2Chapter 13. Models that act
  9. 2026GPT-5.4built directly on GPT-5.3-CodexChapter 14. Where the threads meet now
  10. 2026GPT-5.5built directly on GPT-5.4Chapter 14. Where the threads meet now
  11. 2026GPT-5.6 Solbuilt directly on GPT-5.5Chapter 14. Where the threads meet now
  1. 2024o3 announcedThis milestone.
  2. 2025Deep researchwas influenced by o3 releasedChapter 13. Models that act
  3. 2025o3 releasedsucceeded o3 announcedChapter 12. Thinking longer
  4. 2025gpt-ossbuilt directly on o3 releasedChapter 8. The weights get out
  5. 2025GPT-5built directly on o3 releasedChapter 14. Where the threads meet now
  6. 2025GPT-5.1built directly on GPT-5Chapter 14. Where the threads meet now
  7. 2025GPT-5.2built directly on GPT-5.1Chapter 14. Where the threads meet now
  8. 2026GPT-5.3-Codexbuilt directly on GPT-5.2Chapter 13. Models that act
  9. 2026GPT-5.4built directly on GPT-5.3-CodexChapter 14. Where the threads meet now
  10. 2026GPT-5.5built directly on GPT-5.4Chapter 14. Where the threads meet now
  11. 2026GPT-5.6 Solbuilt directly on GPT-5.5Chapter 14. Where the threads meet now

Direct links and their sources

Where it came from

Built directly on

Influenced by

What it led to

Replaced by