GPT 5.3 Codex
Coding-focused GPT-5.3 variant with optimized routing.
- Reasoning
- Vision
- Native PDF input
- Tool Calling
- Structured Output
Added Feb 24, 2026
Pricing
Auto routing · per 1M tokens- Input
- $1.75
- Output
- $14.00
- Cache read
- $0.18
Specifications
- Context window
- 400K
- Max output
- 128K
- Avg output (7d)
- 1.3K tokens
- Longer than 79% of models
Benchmarks
Benchmarks
Sourced from Artificial Analysis.
Intelligence Index
32.5
Agentic work
T²-Bench Telecom (legacy)
Legacy fallback · Conversational AI agents in dual-control scenarios
86.0%
Better than 78% of models compared
AA-Briefcase
Agentic knowledge work (Elo)
868 Elo
Better than 38% of models compared
Document reasoning
AA-LCR v1.1
Long context reasoning with updated grading
83.3%
Better than 96% of models compared
Reasoning
HLE
Humanity's Last Exam
42.5%
Better than 91% of models compared
IFBench
Instruction-following benchmark
75.4%
Better than 92% of models compared
CritPt
Research-level physics reasoning
16.9%
Coding
Terminal-Bench Hard (legacy)
Legacy fallback · Agentic coding and terminal use
53.0%
Better than 96% of models compared
Knowledge
AA-Omniscience Accuracy
Proportion of correctly answered questions
52.9%
AA-Omniscience Hallucination Rate
Rate of incorrect answers among non-correct responses
89.2%
Legacy benchmarks
GPQA Diamond (legacy)
Graduate-level scientific reasoning
91.5%
Better than 92% of models compared
AA-LCR (unversioned / legacy)
Long context reasoning evaluation
83.3%
Better than 96% of models compared
Last updated Oct 3, 2026
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