Introducing Claude Opus 5.5
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Claude Opus 5.5 is Anthropic's newest frontier AI model, released on September 22, 2026. It is the first model in the new "Claude 5.5" family — with Sonnet 5.5 and Haiku 5.5 confirmed as coming in the following weeks.

The headline: Opus 5.5 performs at Fable 5.1 level on most tasks while costing 40% less to run than Opus 5. Output speed is up 30%+. It is designed as an enterprise-grade workhorse specifically optimized for complex, long-running agentic coding tasks.

It launched the same day as OpenAI's GPT-6 Sol and GPT-6 Luna — a pattern that reliably spikes comparison search volume for weeks. The competitive context: Grok 4.7 undercuts at $2/$6 per million tokens, and Xiaomi's MiMo-V2.6 has entered as a new open-weight frontier model.

Benchmark Scores (Source: Anthropic)

Safety: Opus 5.5 incorporates Fable 5.1-level safeguards covering cybersecurity, biology, and AI development. Thinking cannot be disabled — described by Anthropic as an anti-distillation measure. A 230-page system card was published. Pre-release testing was conducted by external evaluators Frontier Design and METR.

Availability: Claude.ai (Pro/Max/Team/Enterprise), Claude API, Amazon Bedrock, Google Cloud, and Microsoft Azure. Read the full explainer →

The honest answer: Claude Opus 5.5 is NOT free by default. Opus-tier models require a paid subscription (Pro, Max, Team, or Enterprise) or API access. However, there are three legitimate, working methods to access it at zero cost.

Note: Anthropic has previously run brief, unannounced "3 free messages" trials for new Opus models on the free plan (this happened with Opus 5). We recommend watching for a similar window in the coming weeks — but do not count on it.

Read the full free access guide →

Savings vs Opus 5: 20% reduction on input/output, and a massive 60% reduction on cache reads ($0.50 → $0.20). Fast mode is available at $8/$40 per million tokens. US-only inference costs 1.1x standard rates.

Anthropic raised the 5-hour usage limits on all paid tiers (Pro, Max, Team, Enterprise) alongside this launch. See the full pricing analysis →

Claude.ai (Web Interface)

Upgrade to Pro/Max/Team/Enterprise → Start new chat → Select "Claude 5.5 Opus" from the model dropdown.

Claude Code (Terminal)

Run claude in your terminal → Use /model claude-5-5-opus-20260922 to switch. Adjust effort settings with low/medium/high/x-high/max.

Anthropic API

import anthropic

client = anthropic.Anthropic(api_key="your-key")

message = client.messages.create(
    model="claude-5-5-opus-20260922",
    max_tokens=2048,
    messages=[{"role": "user", "content": "Your prompt here"}]
)

print(message.content[0].text)

Cloud Platforms

Available day-one on Amazon Bedrock, Google Cloud Vertex AI, and Microsoft Azure. Read the full setup guide →

Both dropped on September 22, 2026. Here's the head-to-head:

Bottom line: Sol is ~50% cheaper. Opus 5.5 scores higher on coding benchmarks. Pick Sol for cost-sensitive bulk work; pick Opus 5.5 for enterprise-grade agentic coding that demands frontier reasoning. Read the full comparison →

• Price: Input $5 → $4 (20% cut). Output $25 → $20. Cache reads $0.50 → $0.20 (60% cut).
• Speed: 30%+ faster output generation.
• Thinking: Manual toggle replaced by adaptive effort settings (low/medium/high/x-high/max). Cannot be disabled.
• Tool Calling: Forced tool calls retired. Model decides when to invoke tools naturally.
• Safety: New biology classifier added alongside existing cybersecurity safeguards. Now matches Fable 5.1 safety level.
• Communication: Trained to surface progress and findings during long-running tasks. Less silent grinding.
• Token Efficiency: Does more with fewer tokens — particularly on multi-step coding tasks.

Read the full comparison →

Opus 5.5 performs at Fable 5.1 level on most tasks. Both now share the same safety classifiers. The key difference is positioning:

• Opus 5.5: Enterprise workhorse. Built for long-running agentic coding, production deployment, multi-hour sessions. Adaptive effort settings give you fine-grained control over cost vs reasoning depth.
• Fable 5.1: Research and creative powerhouse. Stronger for creative writing, deep document analysis, and tasks requiring manual thinking control.

The bigger picture: Anthropic is consolidating its model family. Sonnet 5.5 and Haiku 5.5 are coming soon, which will complete the 5.5 generation. Read the full comparison →

There is no single "best" model. The right choice depends on your specific task:

Read the full roundup →