Claude Opus 4.6

Overview

Claude Opus 4.6 is Anthropic’s latest Opus-tier model, available on OpenRouter as anthropic/claude-opus-4.6. It is positioned for hard engineering and knowledge-work tasks that unfold over many steps rather than single-turn prompting. OpenRouter describes it as Anthropic’s strongest model for coding and long-running professional work, with improved reliability for complex refactors, debugging, and end-to-end project execution.

A notable change in this release is the 1,000,000-token context window exposed on OpenRouter, which makes Opus 4.6 suitable for very large repositories, long technical documents, and persistent multi-turn sessions. Pricing starts at $5 per million input tokens and $25 per million output tokens, placing it in a premium tier intended for quality-critical workflows where depth and consistency matter more than minimum latency.

Capabilities

• Large context window Supports up to 1,000,000 tokens for long-horizon tasks and broad context retention
• Advanced coding performance Optimized for complex engineering work across multi-file and multi-step workflows
• Reasoning and tool workflows Strong fit for agent-style planning, decomposition, and iterative execution
• Multimodal input support Supports text-plus-image reasoning in Claude 4 generation deployments
• Long-form output quality Produces coherent, detailed outputs for reports, plans, and implementation guidance

Strengths

• Strong reliability on difficult coding and refactoring tasks
• Handles very large context packs without aggressive truncation strategies
• Produces decision-ready long-form outputs in fewer passes
• Well suited to autonomous or semi-autonomous software agents
• Good default choice when correctness and follow-through are prioritized over speed

Limitations and Considerations

• Premium pricing compared with Sonnet, Haiku, and smaller non-Claude models
• Higher latency is expected on deep, long-context tasks
• Cost can grow quickly in iterative loops with large prompts and long completions
• For lightweight or real-time tasks, smaller models are usually more efficient

Best Use Cases

Claude Opus 4.6 is ideal for:

• Large codebase refactors and migration planning
• Multi-step debugging and architecture-level engineering analysis
• Agentic software workflows that require sustained context over many turns
• Technical strategy documents and implementation plans
• Complex professional knowledge work requiring depth and consistency