Claude Opus 4.1 retires on August 5, 2026

What breaks

Production requests pinned to claude-opus-4-1-20250805 will fail once Anthropic retires the model.

• Requests using claude-opus-4-1-20250805 will stop working after retirement.

Affected identifiers and fields

Search your code, environment variables, gateway configuration, and stored request templates for these exact values.

• claude-opus-4-1-20250805

• model
• model retirement
• Claude Opus 4.1

Migration target

Replace the retired model ID with claude-opus-4-8 and regression-test model behavior before the cutoff.

• claude-opus-4-8

What to do

Update the model ID to claude-opus-4-8, then rerun prompt, tool-use, latency, and output-quality tests before August 5.

Before and after

response = client.messages.create(
    model="claude-opus-4-1-20250805",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Summarize this report."}],
)

response = client.messages.create(
    model="claude-opus-4-8",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Summarize this report."}],
)

Official source receipts

These provider pages support the dates, identifiers, symptoms, and migration direction recorded above.