> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.deepmask.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Sonnet 5

> Claude Sonnet 5 by Anthropic — the next-generation balanced flagship. 2M token context, GPQA up to 90.1%, continuous reasoning, and 60-hour autonomous coding at Sonnet-class cost.

Sonnet 5 is Anthropic's next-generation balanced model within DeepMask, carrying the practical intelligence-to-throughput ratio that made the Sonnet 4 series the default for professional engineering into a new generation. It brings Opus-class reasoning and much longer autonomous sessions to the Sonnet tier — so most production agents can run on Sonnet 5 without reaching for Opus.

## About Sonnet 5

**Sonnet 5** (released September 23, 2026) replaces the Standard/High toggle of the Sonnet 4 series with **Continuous Reasoning**, allocating thinking depth dynamically per step at Sonnet-class cost. It extends autonomous coding to 60+ hour single-objective sessions, raises the OSWorld computer-use score to a new high, and reaches a GPQA Diamond score of 90.1%. Its 2M token context window and improved prompt caching keep high-volume workloads efficient, making it the new default for demanding production deployments.

## Key Capabilities

<CardGroup cols={2}>
  <Card title="Continuous Reasoning" icon="infinity">
    Allocates thinking depth dynamically per step rather than per request — Opus-class reasoning quality at Sonnet-class cost.
  </Card>

  <Card title="60-Hour Autonomous Coding" icon="clock">
    Manages week-long engineering objectives with self-correction and testing, maintaining coherence across the full session.
  </Card>

  <Card title="Computer Use (Native)" icon="desktop">
    Sees screens, moves cursors, and types in standard desktop applications — enabling true browser-based and GUI automation without external tools.
  </Card>

  <Card title="Cost-Optimized at Scale" icon="circle-dollar-to-slot">
    Improved prompt caching and batch processing deliver up to 90% cost savings versus standard API calls for high-volume workloads.
  </Card>
</CardGroup>

## Best For

Choose **Sonnet 5** for enterprise-grade agents, full-stack development lifecycle management, and browser-based automation that need near-Opus accuracy at Sonnet cost — especially long-horizon autonomous engineering and multi-app research workflows. For tasks with lower complexity requirements, Haiku 4.5 offers faster throughput at lower cost. For the most demanding reasoning challenges and large multi-agent systems, Opus 5 sets the ceiling.

## Use Cases

* **Autonomous software engineering** — Building, testing, and deploying full-stack features over multi-day sessions from a single prompt.
* **Complex multi-app workflows** — Researching data in a browser and then populating a local Excel sheet and PowerPoint.
* **Enterprise workflow automation** — Analyzing financial data, synthesizing internal insights, and generating professional content at scale.
* **Browser-based agents** — Automating procurement, competitive analysis, and customer onboarding via digital interaction.
* **Legal and financial forensics** — Analyzing massive document sets for subtle logical contradictions.

## Specifications

| Specification | Sonnet 5 |
| - | - |
| Provider | Anthropic |
| Context Window | 2.0M tokens |
| Reasoning | Continuous (dynamic per-step) |
| GPQA Diamond | 90.1% |
| Latency (TTFT) | 0.40s |
| Throughput | 42 tokens/sec |
| Key use cases | Enterprise agents, long-horizon engineering, UI automation |

[Try Sonnet 5 in DeepMask →](https://chat.deepmask.io/)


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