Claude Opus 4.8
Claude Opus 4.8 is an active Anthropic Opus model released before Claude Opus 5, with adaptive thinking and strong behavior for long-horizon coding-agent tasks.
Opus 4.8 remains relevant for validated production prompts and migration testing, but teams starting new complex agentic work should compare it with Opus 5 before choosing a default.
Anthropic still lists Claude Opus 4.8 as active, but the July 24, 2026 Opus 5 launch replaces it as the current Opus recommendation. Official docs remain the source for Opus 4.8 behavior, pricing, and migration details.
- High-complexity coding and platform engineering.
- Long-horizon agentic orchestration with multi-step tasks.
- Hard bug investigation and autonomous change routing.
- Task escalation routing where cost and risk are both tightly managed.
Claude Opus 4.8 remains an active model for complex reasoning and coding-heavy autonomy work. Official model docs confirm 1M context, 128k max output, adaptive thinking, and a supported migration path to Claude Opus 5.
- Claude Opus 4.8 remains active, but it is no longer Anthropic's latest Opus release.
- Effort defaults to high, and prompt-caching behavior is improved versus Opus 4.7.
- Adaptive thinking is the supported reasoning mode; extended thinking budgets are not used on Opus 4.8.
Keep Opus 4.8 where its prompts and tool loops are already validated, then evaluate Opus 5 on the same tasks before migrating. Anthropic prices both models at the same base token rates, so the decision should focus on task success, behavior changes, and migration risk rather than a base-price discount.
- Use Opus 4.8 as a controlled migration baseline rather than the default recommendation for new deployments.
- Opus 4.8 uses a 1M context window by default on API/AWS/Vertex; Microsoft Foundry exposes a 200k context window.
- Re-run task and prompt evaluations because Opus 5 changes thinking defaults and agentic behavior.
Prior Opus generation used as the common migration reference.
Current Opus release and primary migration target for new complex agentic work.
Anthropic public model for high-capability production workflows and long-horizon tasks.
Invitation-only Mythos-tier sibling under Project Glasswing.
Claude Opus 4.8 FAQ
Common questions about Claude Opus 4.8.
When should I use Claude Opus 4.8 instead of Claude Fable 5?+
Use Opus 4.8 when an existing coding or agent workflow has already been validated on it and migration risk outweighs the immediate benefit of switching. For new deployments, compare Opus 5 and Fable 5 first.
Is Opus 4.8 publicly available?+
Yes, Opus 4.8 is part of Anthropic's current Opus family on Anthropic API and partner surfaces. Availability details should be confirmed per account and region in the official API and platform settings.