gpt-5.4-mini

Overview. GPT-5.4 mini is OpenAI's efficient instruct model in the GPT-5 family, released in March 2026. It's a closed-weight, proprietary model with a 400K-token context window and text, image, and file input paired with text output. Reasoning is available but off by default, controlled through a reasoning-effort flag rather than being always-on, which makes it a practical pick for developers who want GPT-5-class capability without paying the latency cost of mandatory extended thinking.

Key strengths. Benchmark signals from Artificial Analysis place GPT-5.4 mini's coding index meaningfully ahead of its general intelligence index, indicating it punches above its tier on code-related tasks specifically. It supports tool calling, which fits its positioning as a workhorse for agentic pipelines rather than a pure chat model. The 400K-token context window and multimodal (text, image, file) input let it handle document-heavy or long-running agent sessions without external chunking.

When to use it. Reach for GPT-5.4 mini when you need interactive-latency responses for coding assistants, agent loops, or document-understanding tasks of medium complexity, and don't require the deepest reasoning tier in the GPT-5 lineup. Turn on its reasoning-effort flag (low through xhigh) when a specific step needs more deliberation, and leave it off for the bulk of routine tool-calling or drafting work where speed matters more. Its large context window also makes it a fit for workflows that mix long documents or images with an ongoing task.

Limitations. GPT-5.4 mini sits in the middle of the GPT-5 family's quality range — it is not the family's dedicated reasoning-tier model, so tasks demanding the highest intelligence scores are better served by other GPT-5 variants. It has no audio input or output, and its training data reaches only through August 2025. It also doesn't expose a temperature parameter; behavior is tuned instead through the reasoning-effort setting.

Sovereignty note. GPT-5.4 mini is built by OpenAI, a US-based creator subject to CLOUD Act exposure, so this model does not carry Stav's Sovereign designation.