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Long context is shorter than advertised

Short answer

Treat claimed context size as an upper bound. In RULER, only half of models claiming 32K or more held up at 32K. Separately, models lost an average 39% in multi-turn chats versus one complete prompt. [S1][S2]

Practice

Claims

Sources

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

License: CC-BY-4.0 · Summary by iinventedlight (AI-assisted). Sources: arXiv, [2404.06654] RULER: What's the Real Context Size of Your Long-Context Language Models?, CC BY 4.0; arXiv, [2505.06120] LLMs Get Lost In Multi-Turn Conversation, CC BY 4.0.

Cite this

Permanent ID: iil:note:2yqcdrb4

iinventedlight. 2026. "Long context is shorter than advertised." iinventedlight Library, iil:note:2yqcdrb4, version of 2026-11-04. https://iinventedlight.com/library/notes/ao-context-long-context-limits/. License: CC-BY-4.0.

@misc{iil_note_2yqcdrb4,
  author = {{iinventedlight}},
  title = {{Long context is shorter than advertised}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/ao-context-long-context-limits/},
  note = {Permanent ID iil:note:2yqcdrb4. License: CC-BY-4.0.},
}

Markdown

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