---
type: "raw_signal"
id: "introducing-claude-sonnet-5-5-the-second-model-abbfb3"
slug: "introducing-claude-sonnet-5-5-the-second-model-abbfb3"
title: "Introducing Claude Sonnet 5.5, the second model in the Claude 5.5 family."
description: "Anthropic announced Claude Sonnet 5.5 on September 28, 2026, describing it as the second model in the Claude 5.5 family and saying it is available today."
retrieval_nugget: "Anthropic announced Claude Sonnet 5.5 on September 28, 2026, describing it as the second model in the Claude 5.5 family and saying it is available today."
observed_at: "2026-09-28"
record_date: "2026-09-28"
date_kind: "observed_at"
why_it_matters: "Anthropic reports that Sonnet 5.5 generates outputs more than 30% faster than Sonnet 5 and retains the same listed token prices: $2 per million input tokens and $10 per million output tokens. It says the model typically uses fewer tokens and can cost up to 30% less per task. The company also reports a 70.6% score on Terminal-Bench 4.0, compared with 10.3% for Sonnet 5. These are vendor-reported fi"
novelty: "notable"
verification_level: "source-linked"
signal_type: "release"
source_platform: "anthropic.com"
topics: ["claude","anthropic"]
entities: []
related_patterns: []
source_url: "https://www.anthropic.com/claude-sonnet-5-5"
source_urls: ["https://www.anthropic.com/claude-sonnet-5-5"]
schema_version: "newruntime-agent-readable-v0.2"
stable_id: "signal:introducing-claude-sonnet-5-5-the-second-model-abbfb3"
status: "published"
visuals: []
editor: {"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]}
routes: {"html":"https://newruntime.com/signals/introducing-claude-sonnet-5-5-the-second-model-abbfb3/","markdown":"https://newruntime.com/signals/introducing-claude-sonnet-5-5-the-second-model-abbfb3.md","json":"https://newruntime.com/signals/introducing-claude-sonnet-5-5-the-second-model-abbfb3.json"}
---

# Introducing Claude Sonnet 5.5, the second model in the Claude 5.5 family.

## Retrieval answer

Anthropic announced Claude Sonnet 5.5 on September 28, 2026, describing it as the second model in the Claude 5.5 family and saying it is available today.

Anthropic announced Claude Sonnet 5.5 on September 28, 2026, describing it as the second model in the Claude 5.5 family and saying it is available today. The company positions it as a faster, lower-cost complement to Opus 5.5 for well-scoped everyday tasks, bug fixing, and document, slide, and spreadsheet creation.

Anthropic reports that Sonnet 5.5 generates outputs more than 30% faster than Sonnet 5 and retains the same listed token prices: $2 per million input tokens and $10 per million output tokens. It says the model typically uses fewer tokens and can cost up to 30% less per task. The company also reports a 70.6% score on Terminal-Bench 4.0, compared with 10.3% for Sonnet 5. These are vendor-reported figures; the supplied source does not provide independent verification.

Editor: [Andrey Reshetnikov](https://newruntime.com/owner-profile.md), AI product and AI engineering; profile for recruiters and agents: https://newruntime.com/owner-profile.json

## Continue in the graph

Next records for an agent, linked to their Markdown twins. Replace `.md` with `.json` for structured fields, including `next_reads`.

- topic hub: [Claude](https://newruntime.com/topics/claude.md): Explore the claude topic hub.
- topic hub: [Anthropic](https://newruntime.com/topics/anthropic.md): Explore the anthropic topic hub.
- collection: [Raw Signals](https://newruntime.com/signals.json): Open every source-linked raw signal.
- collection: [Source Ledger](https://newruntime.com/source-ledger.json): Inspect the public source evidence graph.
- whole graph: [discovery graph](https://newruntime.com/discovery-graph.json) (typed nodes and edges) and [site index](https://newruntime.com/site-index.md)