Claude Opus 4.8 - Anthropic's flagship large language model

What is Claude Opus 4.8

Claude Opus 4.8 is Anthropic's flagship large language model, building on Opus 4.7 to improve judgment, honesty, and long-horizon independent work capabilities, leading across the board in benchmarks such as coding, agentic reasoning, and multidisciplinary reasoning, ahead of GPT-5.5 and Gemini 3.1 Pro, with API pricing unchanged and fast mode costs reduced to one-third.

Key features of Claude Opus 4.8

• Agentic coding: Achieves 69.2% on SWE-Bench Pro, supporting autonomous completion of end-to-end software engineering tasks.
• Terminal coding: Scores 74.6% on Terminal-Bench 2.1, with strong command-line tool use and scripting capabilities.
• Multidisciplinary reasoning: 49.8% on Humanity's Last Exam without tools and 57.9% with tools, surpassing all mainstream competitors.
• Agentic computer use: Scores 83.4% on OSWorld-Verified, able to autonomously operate graphical interfaces to complete complex tasks.
• Knowledge work: Scores 1890 on GDPval-AA, performing best in real-world work scenarios such as document analysis and deep research.
• Agentic financial analysis: Scores 53.9% on Finance Agent v2, supporting complex financial statement reasoning and high-precision citations.
• Dynamic workflows: In Claude Code, it can autonomously plan and launch hundreds of subagents in parallel to handle ultra-large-scale tasks.
• Effort control: Users can manually adjust the model's thinking depth and resource consumption level (low/high/extra/max).
• Fast mode: Runs 2.5 times faster than regular mode, with API cost only one-third that of the previous generation's fast mode.

Technical principles of Claude Opus 4.8

• Honesty alignment training: Through specialized training, reduces the probability of the model making unsupported assertions and proactively flags its own uncertainty.
• Safety evaluation: Conducts detailed alignment evaluations before release; the rate of misaligned behavior is on par with Mythos Preview.
• Subagent parallel architecture: Dynamic workflows use a distributed architecture with a main agent orchestrating and hundreds of subagents executing in parallel.
• Long-running support: Supports continuous task execution over several days, can resume after interruption, and is suitable for large-scale code migration.
• System entries API: The Messages API supports receiving system entries within the conversation array, enabling dynamic updates of runtime instructions.
• Multimodal fusion: Has multimodal understanding and reasoning capabilities to directly reason over unstructured content such as PDFs and charts.

How to use Claude Opus 4.8

• API access: Call via the Anthropic API; input tokens cost $5 per million and output tokens cost $25 per million.
• Launch dynamic workflows: In the Claude Code environment, enter the "workflow" keyword to launch large-scale parallel tasks.
• Adjust effort: Switch between low/high/extra/max effort levels next to the model selector in claude.ai and Claude Code.
• Switch to fast mode: Select Fast Mode in the API or client to run at 2.5x speed and lower cost.
• Enterprise permissions: Dynamic workflows are currently available to Enterprise, Team, and Max users.
• Use on third-party platforms: IDEs such as Cursor have made Opus 4.8 available right away, so you can switch directly in your development environment.

Claude Opus 4.8's core advantages

• Leading across benchmarks: Outperforms GPT-5.5 and Gemini 3.1 Pro on 5 of 6 core benchmarks.
• Significantly improved honesty: The probability of failing to flag code defects without prompting drops to about one quarter of the previous generation, greatly reducing the risk of hallucinations.
• Reliability on long-duration tasks: Supports continuous operation for several days and can handle large-scale cross-language migration projects involving hundreds of thousands of lines of code.
• Controllable cost: Pricing remains unchanged in standard mode, Fast Mode cost drops to one third, and token consumption efficiency improves by about 25%.
• Best safety alignment: The incidence of misaligned behavior is significantly lower than Opus 4.7, reaching Anthropic's best safety level to date.
• Flexible effort: Users can freely adjust the model's depth of thinking based on task difficulty to achieve the best balance between quality and speed.

Claude Opus 4.8 project address

• Project official website：https://www.anthropic.com/news/claude-opus-4-8

Comparison of Claude Opus 4.8 with similar competitors

Claude Opus 4.8 application scenarios

• Large-scale code migration: Use dynamic workflows to complete cross-language porting of hundreds of thousands of lines of code, such as Bun's migration from Zig to Rust.
• Enterprise-grade software development: As a backend model for IDEs such as Cursor, assists in completing end-to-end software engineering tasks.
• Complex financial analysis: Process dense financial reports and legal documents, providing financial document workflows with high-precision citations and reasoning.
• In-depth academic research: Provide high-quality analysis for multidisciplinary reasoning tasks at the level of Humanity’s Last Exam.
• Professional legal services: Handle high-stakes substantive legal work in legal Agent platforms such as CoCounsel Legal.
• Data and knowledge work: Directly reason over unstructured content such as PDFs and charts in AI Agents such as Databricks Genie.