OpenAI API · api · fg-0137

Code calling gpt-3.5-turbo, gpt-4, gpt-4-turbo, o1, o3-mini or o4-mini breaks on 2026-10-23

Model ids that coding assistants still suggest by default stop being served

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

OpenAI retires the legacy GPT snapshots, including gpt-3.5-turbo, gpt-4, gpt-4-turbo, gpt-4o-2024-05-13, o1, o1-pro, o3-mini and o4-mini, on 2026-10-23. Older code and model defaults hardcode these names.

Fix

Replace each model with its listed substitute: gpt-3.5-turbo and o4-mini move to gpt-5.6-terra; gpt-4, gpt-4-turbo, gpt-4o-2024-05-13, o1 and o3-mini move to gpt-5.6-sol; o1-pro moves to gpt-5.6-sol with reasoning.mode pro; gpt-4.1-nano moves to gpt-5.6-luna. Keep the model id in configuration so the next retirement is a one line change.

Apply

const REPLACEMENT = {
  'gpt-3.5-turbo': 'gpt-5.6-terra',
  'gpt-4': 'gpt-5.6-sol',
  'gpt-4-turbo': 'gpt-5.6-sol',
  'gpt-4o-2024-05-13': 'gpt-5.6-sol',
  'gpt-4.1-nano': 'gpt-5.6-luna',
  'o1': 'gpt-5.6-sol',
  'o1-pro': 'gpt-5.6-sol', // with reasoning: { mode: 'pro' }
  'o3-mini': 'gpt-5.6-sol',
  'o4-mini': 'gpt-5.6-terra',
};

Affects: OpenAI API legacy snapshots, shutdown 2026-10-23; gpt-4o and gpt-4.1 snapshots follow on 2027-01-14

Sources

• https://developers.openai.com/api/docs/deprecations

claude mcp add --transport http footgun https://getfootgun.com/api/mcp