# Claude Opus 5.5 context window

entity: /record/claude-opus-5-5.md  
predicate: context_window  
page: /record/claude-opus-5-5/context_window  
as_of: 2026-11-04  

As of November 4, 2026, Claude Opus 5.5's context window on the AsOf record is 1 M tokens, dated September 22, 2026, from a primary source (platform.claude.com). The record holds 1 claim on Claude Opus 5.5's context window, 1 still open and 0 superseded, each dated and sourced; a replaced value is closed with an end date, never deleted.

## Current context window

What the record asserts on 2026-11-04.

- [Claude Opus 5.5](/record/claude-opus-5-5.md) | context_window | 1M tokens | valid 2026-09-22 to present | conf 0.95 | valid | [clm_C8F8497EE25C](/claim/clm_C8F8497EE25C.md)
  sources: https://platform.claude.com/docs/en/release-notes/overview

## Every dated value

One claim per line, oldest first. Superseded claims stay visible.

- [Claude Opus 5.5](/record/claude-opus-5-5.md) | context_window | 1M tokens | valid 2026-09-22 to present | conf 0.95 | valid | [clm_C8F8497EE25C](/claim/clm_C8F8497EE25C.md)
  sources: https://platform.claude.com/docs/en/release-notes/overview

## Questions this record answers

### What is Claude Opus 5.5's current context window?

1 M tokens, dated September 22, 2026, from a primary source (platform.claude.com). The record asserts this claim as of November 4, 2026 (status valid, confidence 0.95).


## Get this data

- JSON: /v1/entities/claude-opus-5-5/context_window (this fact) · /v1/entities/claude-opus-5-5?predicates=context_window (with the entity's coverage; add as_of=YYYY-MM-DD for a date)
- MCP: timeline(entity: "claude-opus-5-5", predicates: ["context_window"]) for every dated value · fetch(id: "/record/claude-opus-5-5/context_window.md") for this page
- Entity twin: /record/claude-opus-5-5.md · timeline: /timelines/claude-opus-5-5.md

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AsOf is a temporal fact ledger: a structured, dated, sourced record of what is true and what changed, built for AI retrieval.