Claude Sonnet 4.5: A Hybrid Reasoning Model for Advanced Agents and Coding
Anthropic Claude Sonnet 4.5 blends exceptional intelligence, long-horizon reasoning, and reliable tool usage to power complex agents and end-to-end coding.
Anthropic Claude Sonnet 4.5 blends exceptional intelligence, long-horizon reasoning, and reliable tool usage to power complex agents and end-to-end coding.
Trusted by users from 10,000+ companies
Claude Sonnet 4.5 thrives on complex, long-running workstreams which keeps context, improves plans, and coordinates tools with unusual reliability.

Claude Sonnet 4.5 supports “extended thinking mode” where it alternates between reasoning, tool interaction, and incremental progress tracking. It allows the tool to use multiple tools, clear stale context, and sustain focus over large scopes.

With a 200K context window and up to 64K output tokens, it can plan, reason, and generate at enterprise scale without losing the thread. Enhanced tool coordination helps it synthesize information faster and deliver more consistent outcomes.

The model is built for long-horizon coding and agentic workflows. Anthropic reports it managed over 30 hours of autonomous coding and refactoring while maintaining coherence and context.
Workflows that span hours, files, or sessions no longer stall or reset prematurely. With extended context window, memory-tools and autonomous progress tracking, the model stays engaged and consistent over longer time spans.

Claude Sonnet 4.5 helps organizations adopt advanced AI with confidence while maintaining clear oversight.
Built with ASL-3 protections and improved behavioral guardrails, minimizing sycophancy, deception, and unsafe outputs for dependable deployment.
Hardened against adversarial prompts and web-borne manipulations, maintaining task objectives and safeguarding tools, credentials, and sensitive organizational context.
Optional memory incorporates important facts beyond the context window, enabling continuity across sessions and smoother long-horizon, multi-phase initiatives.
Save progress snapshots and instantly roll back during extensive tasks, reducing risk while experimenting, refactoring, or exploring alternative solution branches.
Automatically prunes stale context and tool traces near limits, preserving crucial facts so long-running executions remain coherent, efficient, and accurate.
Granular, auditable permissions frameworks govern tool access, file operations, and environment scopes, enabling compliant agent behavior across varied organizational environments.
Accessible via API and major clouds, with desktop and mobile apps, fitting diverse workflows without infrastructure overhaul or vendor lock-in.
Create, edit, and execute code, spreadsheets, documents, and slides directly in chat, streamlining production while keeping collaboration centralized and traceable.
Clear action traces, summaries, and incremental updates improve oversight, making review, handoffs, and audits faster without sacrificing autonomy or quality.
Still have questions? Here are some of the most common queries from users.