• Hybrid reasoning: supports both fast (“near-instant”) and extended thinking modes.
• Optimised for responsiveness, cost and high-volume production workloads.
• Strong coding performance relative to prior Sonnet versions (improved over Sonnet 3.7).
• Available even in free tiers (alongside paid plans).
• Better suited for general-purpose use and agents where speed + cost-efficiency matter.

1. Best Intelligence at Scale

• OpenAI positions GPT-5.4 as its frontier model for agentic, coding, and professional workflows.
• Built for complex professional work where stronger reasoning and higher answer quality matter.

2. Configurable Reasoning + Multimodal Input

• Supports configurable reasoning effort from none to xhigh, letting teams balance speed and depth.
• Accepts both text and image inputs while producing text output.

3. Massive Context for Long-Running Work

• 1.05M token context window supports very large codebases, documents, and multi-step workflows.
• Allows up to 128 k output tokens for long-form answers and larger generations.

4. Updated Knowledge & Broad Tool Support

• Knowledge cut-off of Aug 31 2025 keeps it current for newer frameworks and business context.
• Supports tools like web search, file search, code interpreter, hosted shell, computer use, and MCP in the Responses API.