GPT-5.4 mini
A smaller, lower-cost OpenAI language model in the GPT-5.4 family.
HN commenters like it as a fast, token-efficient model for implementing coding features1234, and some find it good at code review.5 Those reporting good results rely on guardrails and structured prompts67, and one commenter groups it with models that produce hallucinated output.8
Why people recommend it
Coding implementation · 3
Used to implement features, screens, APIs and components in coding workflows.
“I use 5.4 mini all time for coding. No trouble letting it implement features.”
“Kimi K2.5, Composer 2.5, GPT-5.4 mini, etc. for faster implementation”
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“I switched to GPT-5.4-mini, which uses far fewer tokens, and it’s often just as good as Sonnet.”
Speed · 2
Chosen as a faster model for implementation and delegated tasks.
“I like the ability to start "tasks" with faster models like gpt5.4-mini for certain tasks”
“Kimi K2.5, Composer 2.5, GPT-5.4 mini, etc. for faster implementation”
Token efficiency · 1
Uses far fewer tokens than Sonnet and is often about as good.
“I switched to GPT-5.4-mini, which uses far fewer tokens, and it’s often just as good as Sonnet.”
Code review · 1
Considered quite good at code review when run in focused, iterative cycles.
“I found Luna and even 5.4-mini to be quite good at code review”
Caveats and dissent
Needs guardrails · 2
Good results depend on guardrails, clear instructions and structured review setups.
“I use 5.4 mini all time for coding. No trouble letting it implement features.”
“I found Luna and even 5.4-mini to be quite good at code review”
Hallucinations · 1
One commenter places it in a tier of models that produce hallucinated output.
“"I love hallucinated garbage": Sonnet, Qwen 3.6, GPT 5.4 mini, GPT 5.3 Codex”
Not top-tier · 2
Even supporters say it is not the best model available.
“I use 5.4 mini all time for coding. No trouble letting it implement features.”
“"I love hallucinated garbage": Sonnet, Qwen 3.6, GPT 5.4 mini, GPT 5.3 Codex”
Often compared with
Threads where it came up
- GPT-5.6 Luna vs. GPT-6 Astra: Is a $1.20 Model Good Enough for Code Review? 1 mention
- Portal by Spotify cut my Claude Code token usage by 90% 1 mention
- Google fixed more Chrome bugs in June than over the past two years, thanks to AI 1 mention
- GLM 5.2 Is Out 1 mention
- Show HN: Boxes.dev: ditch localhost; run Claude Code and Codex in the cloud 1 mention
- Anthropic no longer allowing Claude Code subscriptions to be used with OpenClaw 1 mention
Also written as GPT-5.4-mini, GPT 5.4 mini, GPT 5.4 Mini. Data: gpt-5-4-mini.json. Quotes are verbatim; the verdict and theme labels are written by a model from these comments, and every clause links to its sources.
All comments 6
“I found Luna and even 5.4-mini to be quite good at code review”
“I switched to GPT-5.4-mini, which uses far fewer tokens, and it’s often just as good as Sonnet.”
“"I love hallucinated garbage": Sonnet, Qwen 3.6, GPT 5.4 mini, GPT 5.3 Codex”
“I use 5.4 mini all time for coding. No trouble letting it implement features.”
“Kimi K2.5, Composer 2.5, GPT-5.4 mini, etc. for faster implementation”
“I like the ability to start "tasks" with faster models like gpt5.4-mini for certain tasks”