GPT-5.4

GPT-5.4 is an OpenAI reasoning model presented in the API & Codex Build Hour as a token-efficient coding and agent model with native computer-use capabilities.

Key facts

• Type: Reasoning / coding / computer-use model
• Maker: OpenAI
• Codex role: Presented as a major Codex model release and one of the models behind the shift from pair programming to agent delegation ^[src-084].
• Context length: OpenAI describes GPT-5.4 as supporting up to a million tokens of context ^[src-084].
• Computer use: The session describes native computer-use-agent capabilities and a new API surface for managing browsers and computers ^[src-084].
• Tool search: GPT-5.4 is paired with a tool search capability for progressively discovering tool namespaces instead of loading hundreds of tools into context at once ^[src-084].
• Efficiency: OpenAI frames it as a token-efficient reasoning model, matching strong coding performance with lower token consumption and latency than earlier Codex models ^[src-084].

Related

• See also: OpenAI, Codex (OpenAI), GPT 5.5
• Concepts: Agentic Engineering, Harness Engineering, Progressive Context Loading (Skills), Claude Code Token Economics

Source references

• ^[src-084] OpenAI Codex, Workspace Agents, Prompt Caching, and Superintelligence Policy cluster (2026-02-09 to 2026-05-08)