Anthropic Launches Claude Opus 4: Longer Context, Better Reasoning
Category: News · Stage: Awareness
By Max Beech, Head of Content
Anthropic launched Claude Opus 4 on October 28, 2025—their flagship model competing with GPT-4o and Gemini Pro. Two headline features: 500K token context window (double Opus 3.5's 200K) and enhanced reasoning mode competing with OpenAI o1.
What's New in Opus 4
1. Extended Context (200K → 500K tokens)
500K tokens ≈ 375,000 words ≈ 750 pages of text.
Use cases enabled:
- Entire codebases (analyze full repo, not excerpts)
- Long documents (legal contracts, research papers, books)
- Extended conversations (months of chat history in context)
Pricing: $15 per million input tokens (vs $3 for Sonnet 4)—expensive but justified for context-dependent work.
2. Reasoning Mode
Competitive with OpenAI o1-mini and Google Gemini 2.0 Flash Thinking.
Approach: Extended thinking time (10-60 seconds) for complex problems requiring multi-step logic.
Performance:
- GPQA (science): 64.2%
- MATH benchmark: 76.8%
- Competitive with o1-mini, trails o1 full model
Pricing: Standard Opus 4 pricing (no premium for reasoning mode—unlike OpenAI's separate o1 pricing)
3. Improved Instruction Following
Benchmarks show 18% improvement in following complex multi-step instructions vs Opus 3.5.
Real-world impact: Better at structured outputs (JSON, specific formats), complex workflows, edge case handling.
Competitive Positioning
| Model | Context | Reasoning | Price (per 1M tokens) | |-------|---------|-----------|---------------------| | Claude Opus 4 | 500K | Good | $15 input | | GPT-4o | 128K | Basic | $5 input | | OpenAI o1 | 128K | Excellent | ~$100+ (estimated) | | Gemini Pro | 1M | Basic | $2 input | | Gemini 2.0 Flash Thinking | 128K | Good | Free/low-cost |
Claude's niche: Maximum context window for complex document analysis, competitive reasoning at lower price than o1.
Productivity Tool Implications
Tools likely to integrate:
1. Notion AI
- Use 500K context for entire workspace analysis
- "Summarize all my project documentation" becomes feasible
2. Cursor / GitHub Copilot competitors
- Load entire codebase into context
- Better cross-file code understanding
3. Legal/research tools
- Analyze full legal documents (contracts, depositions)
- Research paper synthesis across multiple sources
4. Meeting AI tools
- Maintain months of meeting history in context
- Long-term pattern analysis ("What were our Q1-Q3 priorities?")
Pricing Considerations
Cost comparison:
Scenario: Analyze 400-page document (200K tokens)
- Claude Opus 4: $3.00
- GPT-4o: Multiple passes required (128K limit) ≈ $2.50-4.00
- Gemini Pro: $0.40 (much cheaper but potentially lower quality)
When Opus 4 worth the premium:
- Quality-critical work (legal, medical, financial)
- Complex reasoning required
- Single-pass analysis preferable (vs chunking with GPT-4o)
When cheaper alternatives work:
- High-volume simple tasks
- Budget constraints
- Quality threshold met by Gemini/Sonnet
Key Takeaways
- Claude Opus 4 ships with 500K token context (2.5× GPT-4o, 0.5× Gemini Pro) and competitive reasoning mode
- Pricing at $15/1M input tokens positions between mid-tier (GPT-4o $5) and premium reasoning models (o1 ~$100)
- Best for: Complex document analysis, full codebase understanding, long-context reasoning tasks
- Productivity tools (Notion, code editors, legal tech) likely to integrate for specialized use cases
- Market fragmentation: No single "best" model—choose by context needs, reasoning requirements, and budget
Sources: Anthropic announcement (Oct 28, 2025), benchmark data, pricing documentation