Claude Opus 4.1 was announced August 5, 2025 as an incremental improvement over Opus 4, particularly in coding, research and tasks requiring careful detail tracking. Although its name differs by only one decimal point, the `claude-opus-4-1-20250805` ID is a separate release that should receive its own source record and migration test.
Historical research cutoff: 25 October 2026. Primary-source historical claims are date-scoped; cloud entitlements, region-specific availability, current pricing and rate limits are not implied.
Release identity at a glance
- Provider
- Anthropic
- Model family
- Claude Opus 4.1
- Public launch
- 2025-08-05
- API ID / checkpoint
- claude-opus-4-1-20250805
- API retirement status
- 2026-08-05
The release and why it mattered
Anthropic published results on SWE-bench Verified and discussed changes to multi-file code refactoring. Those are launch claims with specific evaluation scaffolds and should not be turned into a general statement that Opus 4.1 always writes better software than every contemporary alternative. Both agent tools and repository test infrastructure influence the result.
Capabilities and genuine use cases
Opus 4.1 was available through Anthropic API and selected cloud partners at release. Developers might choose it for reviewing unfamiliar code, reasoning over research notes or planning careful modifications. A workflow that writes to a repository still requires staged diffs, tests and an explicit approval boundary outside the model.
Integration and version identity
Anthropic announced the model’s deprecation in June 2026 and lists August 5, 2026 as its retirement date on Anthropic-operated services. This cutoff falls before October 25, so the correct status is historical/retired, not “available to try.” Keep cloud-platform schedules distinct and preserve historical request/response evidence when evaluating a replacement.
Limits and evidence gaps
An unchanged per-token rate at its 2025 launch does not imply present-day pricing. It also does not establish the security posture of any vendor’s IDE tooling. This article is about the underlying model; AI 06 covers products that package Claude for code editing and automation.
How to choose or migrate
Use this release to demonstrate why model pinning is necessary even across minor version labels. For live engineering workflows, validate a supported model against a fixed repository benchmark including failed patches, rollback behavior and human sign-off.
Reproducible evaluation checklist
For older Claude services, compare the vendor-operated API lifecycle with the lifecycle published by the actual cloud partner. Exercise long inputs, structured outputs and tool argument validation as separate acceptance tests. Do not assume that matching family names imply identical backend checkpoints.
Collect the exact Messages API version, system instructions and model string from a reproducible request. An active cloud model and a retired direct-API model can coexist under similar product naming.
Sources & Further Reading
- www.anthropic.com — documentation/reference (supplier-provided reference; not independently checked in this pass)
- platform.claude.com — documentation/reference (supplier-provided reference; not independently checked in this pass)
Source documentation establishes vendor-published facts, not independently measured model quality, tenant access, contractual rights or current prices. Use a dated pricing ledger and an account-specific entitlement check for deployment decisions.