Claude Sonnet 4

Model at Anthropic

113th of 270 on Epoch Capabilities Index

Claude Sonnet 4 does not have a researched profile yet. Everything here comes from its recorded changes and public listings, each linked to its source.

The basics

As of Nov 1

Status: Retired Jun 15, 2026

Updates

Jun 15

Retired

Claude Sonnet 4 and Claude Opus 4 retired

Requests to claude-sonnet-4-20250514 and claude-opus-4-20250514 on the Claude API now return an error.

Action needed:: Switch to Claude Sonnet 4.6 or newer and Claude Opus 4.8 or newer.

Apr 30

Breaking change

1M context beta retired for Sonnet 4.5 and Sonnet 4

The context-1m-2025-08-07 beta header stopped working for Claude Sonnet 4.5 and Sonnet 4, so requests over 200k tokens now fail.

Action needed:: Move long-context work to Claude Sonnet 4.6 or newer.

Apr 14

Retiring

Claude Sonnet 4 and Claude Opus 4 deprecated

Anthropic announced that claude-sonnet-4-20250514 and claude-opus-4-20250514 would retire on the Claude API on June 15, 2026.

Action needed:: Migrate to Claude Sonnet 4.6 and Claude Opus 4.8.

Full changelog, by month

Role

Mid-size model at Anthropic

Claude Sonnet 4
Until Jun 2026

Works with

From recorded changes

Claude Code

Agent · 1 shared change

Similar models

Claude Sonnet 5.5

$2 in, $10 out

Claude Sonnet 5

$2 in, $10 out

Claude Sonnet 4.5

$3 in, $15 out

Similar models for now. Real viewing data comes after launch.

Benchmarks

Higher is better. Green is Claude Sonnet 4. Dark marks are similar models.

Independent

What people say

Reviews

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Writing habits

Creative writing · EQ-Bench, among 51 models tracked here

Slop score

19.6

Overused AI words and phrases. Less slop than 34% of tracked models.

Repetition

4.3

Repeated words and ideas. Less repetition than 24% of tracked models.

Story length

6,125

Average characters per story. Longer than 46% of tracked models.