GPT-5.1 Codex
JSON →An incremental update to GPT-5 Codex with improved code generation and debugging capabilities.
Specs
context window 272K tokens
max output 128K tokens
input price $1.25 / 1M tokens
output price $10 / 1M tokens
Capabilities
code-generationfunction-callingstreamingjson-modetool-usevisionprompt-cachingreasoning
Dates
releasedNov 2025
knowledge cutoffJun 2025
Resources
API
full doc /v1/models/gpt-5.1-codex