Anthropic just released Claude 4, and it is not a minor update. This is the most capable model Anthropic has ever shipped, and it competes directly with GPT-5 in nearly every benchmark.
Here is everything you need to know about what Claude 4 does, how it performs, and whether it is the right model for your work.
What Is Claude 4?
Claude 4 is Anthropic's fourth-generation large language model, designed around three principles: capability, reliability, and safety. It is the first Claude model to offer native multimodal support (text and images), and it ships with the largest context window of any commercial model at 200,000 tokens.
The model comes in three variants:
- Claude 4 Haiku: Fast, cheap, ideal for high-volume tasks
- Claude 4 Sonnet: Balanced performance and cost
- Claude 4 Opus: Maximum capability, complex reasoning
Benchmark Performance
Claude 4 Opus scores 92% on MMLU (Massive Multitask Language Understanding), beating GPT-5's 89% on that specific benchmark. On the MATH benchmark, Claude 4 achieves 87.3% accuracy, compared to GPT-5's 85.8%.
Where Claude 4 stands out most clearly:
- Legal document analysis: 94% accuracy on contract clause identification (human lawyers: 91%)
- Medical literature summarization: Outperforms GPT-5 by 8 percentage points
- Long document QA: Near-perfect recall at 150K tokens vs GPT-5's degradation after 100K
- Code generation with safety review: 78% of Claude Code outputs pass security audits on first try
Where GPT-5 still wins: Creative writing variety, image generation (GPT-5 has DALL-E integration), and breadth of real-time tool integrations.
Real-World Scenario: Legal Contract Review
A mid-size SaaS company's legal team handles 40-60 vendor contracts per month. Before Claude 4, each contract took an associate 3-4 hours to review.
Their workflow now:
- Upload contract PDF to Claude 4 Opus (fits easily in 200K context)
- Prompt: "Review this agreement. Identify unusual indemnification clauses, any terms that deviate from standard SaaS vendor agreements, and flag items requiring partner approval."
- Claude returns a structured analysis in 90 seconds
- Associate reviews the flagged items only (20-30 minutes)
Result: Review time dropped from 3-4 hours to 30-45 minutes per contract. The team now handles 3x the volume without additional headcount.
Claude Code: The Coding Agent
Claude Code is Anthropic's terminal-based coding agent built on Claude 4 Opus. It reads your entire codebase, understands the architecture, makes multi-file changes, runs tests, and handles git operations.
How it works in practice:
A developer working on a Python backend needed to migrate from REST to GraphQL. Instead of spending a week manually converting endpoints, they ran Claude Code with the instruction: "Migrate all REST endpoints in /api to GraphQL, preserve all existing functionality, and add corresponding tests."
Claude Code:
- Read all 47 files in the project
- Identified 18 endpoints
- Generated GraphQL schema, resolvers, and tests
- Updated documentation
- Created a migration guide
Total time: 2.5 hours. Estimated manual time: 5-7 days.
Pricing and Tiers
| Tier | Price | Context | Best For |
|---|---|---|---|
| Claude 4 Haiku | $0.25/M input, $1.25/M output | 200K | High-volume tasks, chatbots |
| Claude 4 Sonnet | $3/M input, $15/M output | 200K | Balanced production use |
| Claude 4 Opus | $15/M input, $75/M output | 200K | Complex analysis, coding |
| API (Pro plan) | $20/month base | 200K | Developers |
Claude.ai subscriptions:
- Free: Limited Claude 4 Sonnet access
- Pro ($20/month): Higher limits, all models, Projects feature
- Team ($25/user/month): Admin controls, usage analytics, SSO
Safety and Reliability
Anthropic's constitutional AI approach means Claude 4 refuses harmful requests more gracefully than most models. It explains what it cannot help with and offers alternatives. For enterprise use cases, this behavior is configurable through system prompts.
Hallucination rates: Claude 4 hallucinates at roughly half the rate of GPT-4-level models on factual benchmarks. It also says "I don't know" more often, which is actually a feature for high-stakes use cases.
Claude 4 vs GPT-5: Honest Comparison
| Task | Claude 4 Opus | GPT-5 |
|---|---|---|
| Legal document analysis | Better | Good |
| Long document recall | Better | Good |
| Creative writing | Good | Better |
| Code generation | Better | Good |
| Image generation | No (text+image understanding only) | Yes (DALL-E) |
| Real-time web search | Via tools | Native |
| Pricing (Opus/GPT-5) | $15/M input | $15/M input |
Neither model is universally better. Claude 4 wins on document-heavy, safety-sensitive, and long-context tasks. GPT-5 wins on creative tasks and integrated tool ecosystems.
What Claude 4 Is Not Good At
- Real-time information: No native web browsing. Needs tool integration for current data.
- Image generation: Claude understands images but cannot create them. Use DALL-E or Midjourney for generation.
- Deep numerical computation: For heavy math or data analysis, combine Claude with Python/code execution tools.
- Memory across conversations: No persistent memory natively. Use Claude Projects feature or build memory into your system prompt.
How to Get Started with Claude 4
- Go to claude.ai and create an account
- Start with the free tier to test Claude 4 Sonnet
- For document work, try the Projects feature to maintain context across conversations
- For coding, install Claude Code via npm:
npm install -g @anthropic-ai/claude-code - For API integration, get your API key at console.anthropic.com
The Bottom Line
Claude 4 is the best AI model for document-heavy, compliance-sensitive, and long-context work. Its safety features, reliability, and 200K context window make it the default choice for legal, medical, and enterprise applications.
If you are doing creative content, image generation, or need broad tool integrations, GPT-5 may serve you better. But for serious analytical work, Claude 4 is the model to use in 2026.