GPT-5 Codex

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A code-specialized variant of GPT-5, trained extensively on source code for advanced programming tasks.

context window 272K tokens
max output 128K tokens
input price $1.25 / 1M tokens
output price $10 / 1M tokens
code-generationfunction-callingstreamingjson-modetool-usevisionprompt-cachingreasoning
releasedAug 2025
knowledge cutoffApr 2025
full doc /v1/models/gpt-5-codex