Models

Claude Opus 4.1

Anthropic · August 2025

The oldest Opus here. Handles chat, code and reasoning, with the shortest context and output of the family.

Superseded by Claude Opus 4.5 →

  • Modalities

  • Context window

    200,000 tokens, ≈ 150,000 words · about 600 pages

  • Max output

    32,000 tokens, ≈ 24,000 words in a single answer

  • Knowledge cutoff

    January 2025

Providers

Files you can attach

  • ImagesJPG, PNG, GIF, WEBP
  • DocumentsPDF
  • Text and codeTXT, MD, CSV, TSV, RPT, LOG, PY, TS, TSX, JS, JSX, CS, GO, JAVA, KT, SWIFT, CPP, C, H, PHP, RB, SQL, SH, PS1, HTML, CSS, SCSS, JSON, YAML, YML, XML, INI

Tools

  • Web searchSupported
  • Code interpreterNot supported

Features

  • StreamingSupported
  • Function callingSupported
  • Structured outputsSupported
  • Fine-tuningNot supported

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