Claude Opus 4

What It Is

Claude is Anthropic's model family, spanning Haiku (fast, cheap) through Opus (frontier). Claude Opus 4.6, released February 2026, is the current top-of-line model with improved vulnerability finding, coding accuracy, and safety properties. Claude Sonnet 4.6 followed two weeks later with a 1-million-token context window in beta and near-Opus performance at Sonnet pricing.

Why It Matters

Claude stays in Proven, but the economics shifted dramatically this edition. Anthropic cut Opus pricing 67% — from $15/$75 to $5/$25 per million tokens. For teams running production workloads, that changes the math on when to use Opus versus Sonnet. A task that cost $150 in API calls six months ago now costs $50.

The 1M token context window on Sonnet 4.6 (in beta) opens use cases that weren't practical before: processing entire codebases, analysing full contract sets, or maintaining context across long multi-turn agent sessions. Whether it works well enough at that scale for your use case is worth testing — context quality tends to degrade at the extremes.

Key Developments

• Feb 2026: Claude Opus 4.6 released with improved vulnerability detection, coding, and safety capabilities.
• Feb 2026: Claude Sonnet 4.6 released two weeks later with 1M token context window (beta) at Sonnet pricing.
• Feb 2026: Opus pricing cut 67% to $5/$25 per million input/output tokens.
• Jan 2026: Claude Code became the leading terminal-based agentic coding tool (257 reviews, 5.0 rating on Product Hunt).

What to Watch

The 1M context window beta on Sonnet is the feature to test. If quality holds up at scale, it removes one of the last practical arguments for retrieval-heavy architectures on moderately sized document collections. Watch for Anthropic's response to Gemini 3.1 Pro benchmarks — the frontier race is tightening. Also track whether the Opus price cut triggers a broader pricing war with Google and OpenAI.