Claude 4.8 Opus
Anthropic · May 2026
● activeCloseddecoder onlymultimodalAPI Available
Context Window1M tokens
Description
Anthropic's current stable frontier model. Features a 1-million-token context window and 128K-token output — capable of processing entire codebases and generating lengthy, detailed responses. Focused improvements on honesty, more efficient tool use, and reliability for professional workflows.
Notable Milestones
- ▸Launched alongside 'dynamic workflows' in Claude Code
- ▸Introduced effort control settings for users
Key Innovations
Constitutional AI
Constitutional AIAnthropic's approach to AI safety where the model critiques and revises its own outputs against a set of principles.
Reasoning
ReasoningStructured step-by-step problem solving, often using chain-of-thought or tree-of-thought approaches.
Agentic
AgenticModels that can autonomously plan, execute multi-step tasks, use tools, and self-correct without human intervention.
Long Context
Long ContextAbility to process very long inputs (100K+ tokens), enabling analysis of entire codebases or books.