Two August API Deadlines: Opus 4.1 Retires on the 5th, Workbench Prompt Tools Go Dark on the 17th

Anthropic has two hard August deadlines: claude-opus-4-1-20250805 returns errors after August 5, and three /v1/experimental prompt-tools endpoints shut off August 17.

August 5 -- Opus 4.1 retirement. If any of your production code still hardcodes claude-opus-4-1-20250805, it breaks in 10 days. Swap to claude-opus-4-8-20260507 (or just claude-opus-4-8). One gotcha: Opus 4.7 and later dropped the temperature, top_p, and top_k parameters -- passing non-default values now returns HTTP 400, so strip those fields in the same migration pass.

August 17 -- Legacy Workbench and Prompt APIs. The three /v1/experimental/ endpoints (generate_prompt, improve_prompt, templatize_prompt) and the legacy Workbench (platform.claude.com/workbench) are being retired together. If you use these to automate prompt generation or testing, export your saved prompts now from Organizational Settings -- the new Workbench is stateless and does not import old data.

Why it matters: A quiet prod service that's been calling Opus 4.1 for a year will silently break on August 5. Run a quick grep for opus-4-1 in your codebase, CI secrets, and config files before next week.

Sources: Claude model deprecations · Claude Platform release notes · Opus 4.1 migration guide