NLP Lineage

24 July 2026 · Reasoning

Claude Opus 5

Claude Opus 5

Anthropic

Date
24 July 2026
What the date marks
Model release
Kind
Model
Organisation
Anthropic
Access
API only
Threads
In the guided tour
Chapter 14. Where the threads meet now
Learning phases
7. Agents

A milestone: 1 later milestone descends directly from it, and its descendants reach 2 of the 10 threads. How levels are decided

Figures quoted here are reported by the organisation that built it, not independently verified.

Read the primary source (anthropic.com)

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

What it changed

Before it

Frontier capability sat in the gated Fable and Mythos tiers.

The problem

That capability was priced and restricted beyond most users.

What it introduced

A flagship approaching the gated tier's capability at roughly half the price.

Why it matters

It narrowed the gap between the restricted tier and generally available models. This is the model answering you.

What modern models inherit

The current deployed frontier.

What came next

Opus 5.5 in September.

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

Claude Opus 5 has 53 documented ancestors across 10 chapters, reaching back to Recurrent networks in 1990. Showing its direct parents and the 18 turning points among them.

Claude Opus 5 has 53 documented ancestors across 10 chapters, reaching back to Recurrent networks in 1990. Showing all of them.

Claude Opus 5 has 57 recorded ancestors, including indirect ones, across 10 chapters, reaching back to Recurrent networks in 1990. Showing its direct parents and the 18 turning points among them.

Claude Opus 5 has 57 recorded ancestors, including indirect ones, across 10 chapters, reaching back to Recurrent networks in 1990. Showing all of them.

  1. 2026Claude Opus 5This milestone.
  2. 2026Claude Opus 4.8Claude Opus 5 succeeded thisChapter 14. Where the threads meet now
  3. 2026Claude Opus 4.7Claude Opus 4.8 built directly on thisChapter 14. Where the threads meet now
  4. 2026Claude Opus 4.6Claude Opus 4.7 built directly on thisChapter 14. Where the threads meet now
  5. 2025Claude Opus 4.5Claude Opus 4.6 built directly on thisChapter 13. Models that act
  6. 2025Claude Sonnet 4.5Claude Opus 4.5 built directly on thisChapter 13. Models that act
  7. 2025Claude 4Claude Sonnet 4.5 built directly on thisChapter 13. Models that act
  8. 2025Claude 3.7Claude 4 built directly on thisChapter 12. Thinking longer
  9. 2024o1 Turning pointClaude 3.7 was influenced by thisChapter 12. Thinking longer
  10. 2024Claude 3.5 SonnetClaude 3.7 built directly on thisChapter 14. Where the threads meet now
  11. 2024Claude 3Claude 4 succeeded thisChapter 14. Where the threads meet now
  12. 2023SWE-benchClaude Opus 4.5 was influenced by thisChapter 13. Models that act
  13. 2023GPT-4 Turning pointSWE-bench was influenced by thisChapter 7. The assistant goes public
  14. 2023ClaudeClaude 3 built directly on thisChapter 7. The assistant goes public
  15. 2022Constitutional AIClaude 3 built directly on thisChapter 6. Teaching models what people want
  16. 2022GPT-3.5 Turning pointGPT-4 succeeded thisChapter 7. The assistant goes public
  17. 2022HH-RLHFConstitutional AI built directly on this
    Claude was influenced by this    Chapter 6. Teaching models what people want
  18. 2022InstructGPT Turning pointGPT-4 built directly on thisChapter 6. Teaching models what people want
  19. 2022Chain of thought Turning pointo1 was influenced by this
    Constitutional AI was influenced by this    Chapter 12. Thinking longer
  20. 2021HHH assistantHH-RLHF built directly on thisChapter 6. Teaching models what people want
  21. 2021FLANInstructGPT was influenced by thisChapter 6. Teaching models what people want
  22. 2021Codex / HumanEvalSWE-bench built directly on thisChapter 13. Models that act
  23. 2020RLHF for summarisation Turning pointInstructGPT built directly on thisChapter 6. Teaching models what people want
  24. 2020GPT-3 Turning pointCodex / HumanEval built directly on thisChapter 5. Scale becomes a science
  25. 2020Scaling laws Turning pointGPT-4 built directly on thisChapter 5. Scale becomes a science
  26. 2019T5 Turning pointFLAN was influenced by thisChapter 4. Pretrain once, use everywhere
  27. 2019C4 Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  28. 2019RLHF for LMsRLHF for summarisation built directly on thisChapter 6. Teaching models what people want
  29. 2019Sparse Transformer Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  30. 2019GPT-2 Turning pointScaling laws was influenced by this
    GPT-3 built directly on this    Chapter 4. Pretrain once, use everywhere
  31. 2019WebTextGPT-2 was influenced by thisChapter 4. Pretrain once, use everywhere
  32. 2018BERT Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  33. 2018SentencePieceT5 built directly on thisChapter 4. Pretrain once, use everywhere
  34. 2018GPT-1GPT-2 built directly on thisChapter 4. Pretrain once, use everywhere
  35. 2018ELMoBERT was influenced by thisChapter 4. Pretrain once, use everywhere
  36. 2018ULMFiTBERT was influenced by thisChapter 4. Pretrain once, use everywhere
  37. 2017CoVeELMo was influenced by thisChapter 3. Attention, then only attention
  38. 2017Transformer Turning pointScaling laws built directly on thisChapter 3. Attention, then only attention
  39. 2017RLHF originRLHF for summarisation built directly on this
    Constitutional AI was influenced by this    Chapter 6. Teaching models what people want
  40. 2016Layer normTransformer built directly on this
    GPT-2 built directly on this    Chapter 3. Attention, then only attention
  41. 2015Residual connectionsTransformer was influenced by thisChapter 3. Attention, then only attention
  42. 2015LM pretraining Turning pointGPT-1 was influenced by thisChapter 2. Words become vectors
  43. 2015BPE tokenizationGPT-2 built directly on thisChapter 2. Words become vectors
  44. 2015Luong attentionTransformer was influenced by thisChapter 3. Attention, then only attention
  45. 2014AdamTransformer was influenced by thisChapter 2. Words become vectors
  46. 2014GloVeELMo built directly on thisChapter 2. Words become vectors
  47. 2014Seq2seq Turning pointTransformer built directly on thisChapter 2. Words become vectors
  48. 2014Attention Turning pointTransformer built directly on thisChapter 3. Attention, then only attention
  49. 2014GRU / encoder-decoderAttention built directly on thisChapter 2. Words become vectors
  50. 2013word2vecELMo was influenced by thisChapter 2. Words become vectors
  51. 2011NLP from scratchELMo was influenced by thisChapter 1. Language as probability
  52. 2003Neural LMNLP from scratch was influenced by this
    word2vec was influenced by this    Chapter 1. Language as probability
  53. 1997LSTM Turning pointSeq2seq built directly on thisChapter 1. Language as probability
  54. 1990Recurrent networksLSTM was influenced by thisChapter 1. Language as probability
  1. 2026Claude Opus 5This milestone.
  2. 2026Claude Opus 4.8Claude Opus 5 succeeded thisChapter 14. Where the threads meet now
  3. 2026Claude Opus 4.7Claude Opus 4.8 built directly on thisChapter 14. Where the threads meet now
  4. 2026Claude Opus 4.6Claude Opus 4.7 built directly on thisChapter 14. Where the threads meet now
  5. 2025Claude Opus 4.5Claude Opus 4.6 built directly on thisChapter 13. Models that act
  6. 2025Claude Sonnet 4.5Claude Opus 4.5 built directly on thisChapter 13. Models that act
  7. 2025Claude 4Claude Sonnet 4.5 built directly on thisChapter 13. Models that act
  8. 2025Claude 3.7Claude 4 built directly on thisChapter 12. Thinking longer
  9. 2024o1 Turning pointClaude 3.7 was influenced by thisChapter 12. Thinking longer
  10. 2024Claude 3.5 SonnetClaude 3.7 built directly on thisChapter 14. Where the threads meet now
  11. 2024Claude 3Claude 4 succeeded thisChapter 14. Where the threads meet now
  12. 2023SWE-benchClaude Opus 4.5 was influenced by thisChapter 13. Models that act
  13. 2023Process supervisiono1 was influenced by this (indirect influence)Chapter 12. Thinking longer
  14. 2023GPT-4 Turning pointSWE-bench was influenced by thisChapter 7. The assistant goes public
  15. 2023ClaudeClaude 3 built directly on thisChapter 7. The assistant goes public
  16. 2022Constitutional AIClaude 3 built directly on thisChapter 6. Teaching models what people want
  17. 2022GPT-3.5 Turning pointGPT-4 succeeded thisChapter 7. The assistant goes public
  18. 2022HH-RLHFConstitutional AI built directly on this
    Claude was influenced by this    Chapter 6. Teaching models what people want
  19. 2022STaRo1 was influenced by this (indirect influence)Chapter 12. Thinking longer
  20. 2022InstructGPT Turning pointGPT-4 built directly on thisChapter 6. Teaching models what people want
  21. 2022Chain of thought Turning pointo1 was influenced by this
    Constitutional AI was influenced by this    Chapter 12. Thinking longer
  22. 2021HHH assistantHH-RLHF built directly on thisChapter 6. Teaching models what people want
  23. 2021FLANInstructGPT was influenced by thisChapter 6. Teaching models what people want
  24. 2021Codex / HumanEvalSWE-bench built directly on thisChapter 13. Models that act
  25. 2020RLHF for summarisation Turning pointInstructGPT built directly on thisChapter 6. Teaching models what people want
  26. 2020GPT-3 Turning pointCodex / HumanEval built directly on thisChapter 5. Scale becomes a science
  27. 2020Scaling laws Turning pointGPT-4 built directly on thisChapter 5. Scale becomes a science
  28. 2019T5 Turning pointFLAN was influenced by thisChapter 4. Pretrain once, use everywhere
  29. 2019C4 Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  30. 2019RLHF for LMsRLHF for summarisation built directly on thisChapter 6. Teaching models what people want
  31. 2019Sparse Transformer Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  32. 2019GPT-2 Turning pointScaling laws was influenced by this
    GPT-3 built directly on this    Chapter 4. Pretrain once, use everywhere
  33. 2019WebTextGPT-2 was influenced by thisChapter 4. Pretrain once, use everywhere
  34. 2019Transformer-XLSparse Transformer was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  35. 2018BERT Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  36. 2018SentencePieceT5 built directly on thisChapter 4. Pretrain once, use everywhere
  37. 2018GPT-1GPT-2 built directly on thisChapter 4. Pretrain once, use everywhere
  38. 2018ELMoGPT-1 was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  39. 2018ULMFiTGPT-1 was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  40. 2017CoVeELMo was influenced by thisChapter 3. Attention, then only attention
  41. 2017Transformer Turning pointScaling laws built directly on thisChapter 3. Attention, then only attention
  42. 2017RLHF originRLHF for summarisation built directly on this
    o1 was influenced by this (indirect influence)
    Constitutional AI was influenced by this    Chapter 6. Teaching models what people want
  43. 2017ConvS2STransformer was influenced by this (indirect influence)Chapter 3. Attention, then only attention
  44. 2016Layer normTransformer built directly on this
    GPT-2 built directly on this    Chapter 3. Attention, then only attention
  45. 2015Residual connectionsTransformer was influenced by thisChapter 3. Attention, then only attention
  46. 2015LM pretraining Turning pointGPT-1 was influenced by thisChapter 2. Words become vectors
  47. 2015BPE tokenizationGPT-2 built directly on thisChapter 2. Words become vectors
  48. 2015Luong attentionTransformer was influenced by thisChapter 3. Attention, then only attention
  49. 2014AdamTransformer was influenced by thisChapter 2. Words become vectors
  50. 2014GloVeELMo built directly on thisChapter 2. Words become vectors
  51. 2014Seq2seq Turning pointTransformer built directly on thisChapter 2. Words become vectors
  52. 2014Attention Turning pointTransformer built directly on thisChapter 3. Attention, then only attention
  53. 2014GRU / encoder-decoderAttention built directly on thisChapter 2. Words become vectors
  54. 2013word2vecELMo was influenced by thisChapter 2. Words become vectors
  55. 2011NLP from scratchELMo was influenced by thisChapter 1. Language as probability
  56. 2003Neural LMNLP from scratch was influenced by this
    word2vec was influenced by this    Chapter 1. Language as probability
  57. 1997LSTM Turning pointSeq2seq built directly on thisChapter 1. Language as probability
  58. 1990Recurrent networksLSTM was influenced by thisChapter 1. Language as probability

After: what it led to

Claude Opus 5 has 1 documented descendants across 1 chapter, reaching forward to Claude Opus 5.5 in 2026. Showing all of them.

Claude Opus 5 has 1 documented descendants across 1 chapter, reaching forward to Claude Opus 5.5 in 2026. Showing all of them.

Claude Opus 5 has 1 recorded descendants, including indirect ones, across 1 chapter, reaching forward to Claude Opus 5.5 in 2026. Showing all of them.

Claude Opus 5 has 1 recorded descendants, including indirect ones, across 1 chapter, reaching forward to Claude Opus 5.5 in 2026. Showing all of them.

  1. 2026Claude Opus 5This milestone.
  2. 2026Claude Opus 5.5built directly on Claude Opus 5Chapter 14. Where the threads meet now
  1. 2026Claude Opus 5This milestone.
  2. 2026Claude Opus 5.5built directly on Claude Opus 5Chapter 14. Where the threads meet now

Direct links and their sources

Where it came from

Succeeded

Developed alongside

What it led to

Built on directly by