What OpenAI models support thinking, custom temperature, or both?
I ran a quick check against OpenAI models released in the last six months. “Thinking” here means the model accepted reasoning.effort; “custom temperature” means it accepted a non-default temperature parameter in the test.
What’s interesting to me is the number of models where it appears inconsistent. I wonder why this is?
Why does 5.5 NOT support custom temperature, but 5.4 does?
| Model | Created | Thinking | Custom temperature |
|---|---|---|---|
gpt-5.5-2026-04-23 |
2026-04-23 | Supported | Unsupported |
gpt-5.5-pro-2026-04-23 |
2026-04-23 | Supported | Unsupported |
gpt-5.5-pro |
2026-04-22 | Supported | Unsupported |
gpt-5.5 |
2026-04-22 | Supported | Unsupported |
gpt-5.4-mini-2026-03-17 |
2026-03-17 | Supported | Supported |
gpt-5.4-nano-2026-03-17 |
2026-03-17 | Supported | Supported |
gpt-5.4-mini |
2026-03-14 | Supported | Supported |
gpt-5.4-nano |
2026-03-14 | Supported | Supported |
gpt-5.4 |
2026-03-05 | Supported | Supported |
gpt-5.4-2026-03-05 |
2026-03-05 | Supported | Supported |
gpt-5.4-pro-2026-03-05 |
2026-03-05 | Supported | Unsupported |
gpt-5.4-pro |
2026-03-04 | Supported | Unsupported |
gpt-5.3-chat-latest |
2026-02-27 | Supported | Unsupported |
gpt-4o-search-preview |
2026-02-24 | Unknown | Unsupported |
gpt-5.3-codex |
2026-02-08 | Supported | Supported |
gpt-5.2-codex |
2025-12-19 | Supported | Unsupported |
gpt-5.2-2025-12-11 |
2025-12-11 | Supported | Supported |
gpt-5.2-pro-2025-12-11 |
2025-12-11 | Supported | Unsupported |
gpt-5.2-chat-latest |
2025-12-10 | Supported | Unsupported |
gpt-5.2-pro |
2025-12-10 | Supported | Unsupported |
gpt-5.2 |
2025-12-09 | Supported | Supported |
gpt-5.1-codex-max |
2025-11-20 | Supported | Unsupported |
gpt-5.1-codex-mini |
2025-11-13 | Supported | Unsupported |
gpt-5.1-2025-11-13 |
2025-11-13 | Supported | Supported |
gpt-5.1-codex |
2025-11-12 | Supported | Unsupported |
gpt-5.1 |
2025-11-10 | Supported | Supported |
gpt-5.1-chat-latest |
2025-11-07 | Supported | Unsupported |