OpenAI · Frontier
GPT 5.2 Codex
Coding-focused GPT-5.2 variant with optimized routing.
- Reasoning
- Tools
- Vision
- Structured output
- PDF input
- Input
- Text, Images
- Output
- Text
- Reasoning effort
- low · medium · high · xhigh
- Discovery tier
- Frontier
Pricing
USD per 1M tokens- Input
- $1.75
- Output
- $14.00
- Cache read
- $0.18
Reference prices as published by the model provider. API example
Specifications
- Context window
- 400K
- Max output
- 128K
- Average output (7 days)
- 41 tokens
- Longer than 3% of 465 models
Side by side
GPT 5.2 Codex compared
Specifications, prices, speed and benchmark scores next to each other. Benchmarks below show every compared model too.
| GPT 5.2 CodexOpenAIThis model | GPT 5.1 CodexOpenAIRemove | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Discovery tier | Frontier | Balanced |
| Added | Jan 14, 2026 | Nov 13, 2025 |
| Limits | ||
| Context window | 400K | 400K |
| Max output | 128K | 128K |
| Average output | 41 tokens | 22 tokens |
| Pricing, USD per 1M tokens | ||
| Input | $1.75 | $1.25Best |
| Output | $14.00 | $10.00Best |
| Cache read | $0.18 | $0.13Best |
| Benchmark indexes | ||
| Intelligence Index | 28.5Best | 23.7 |
| Math Index | — | 95.7 |
| Capabilities | ||
| Reasoning | Yes | Yes |
| Tools | Yes | No |
| Vision | Yes | Yes |
| Structured output | Yes | No |
| PDF input | Yes | No |
| Reasoning effort | low, medium, high, xhigh | — |
Public evaluations
Benchmarks
Independent evaluation results, with how each score ranks among the models in the Noumen catalog.
- GPT 5.2 Codex
- GPT 5.1 Codex
Intelligence Index
- GPT 5.2 Codex28.5
- GPT 5.1 Codex23.7
GPT 5.2 Codex tested at xhigh reasoning effort
GPT 5.2 Codex: Better than 70% of 326 scored models
Indexes
Math Index
Composite of the math evaluations
- GPT 5.2 Codex: —
- GPT 5.1 Codex: 95.7
Document reasoning
AA-LCRv1.1
Reasoning across long documents
- GPT 5.2 Codex: 82.3%Top
- GPT 5.1 Codex: 69.3%
Reasoning and knowledge
Humanity’s Last Exam
Expert-level questions across academic fields
- GPT 5.2 Codex: 35.7%Top
- GPT 5.1 Codex: 25.7%
GPQA Diamond
Graduate-level science questions
- GPT 5.2 Codex: 89.9%Top
- GPT 5.1 Codex: 86.0%
MMLU-Pro
Multi-subject knowledge and reasoning
- GPT 5.2 Codex: —
- GPT 5.1 Codex: 86.0%
IFBench
Following precise output instructions
- GPT 5.2 Codex: 77.6%Top
- GPT 5.1 Codex: 70.0%
Coding
LiveCodeBench
Recent competitive programming problems
- GPT 5.2 Codex: —
- GPT 5.1 Codex: 84.9%
Math
AIME 2025
Competition mathematics, 2025 problems
- GPT 5.2 Codex: —
- GPT 5.1 Codex: 95.7%
Legacy evaluations
Terminal-Bench Hard
Earlier terminal task suite
- GPT 5.2 Codex: 37.1%Top
- GPT 5.1 Codex: 34.8%
τ²-Bench Telecom
Tool use in a customer-support simulation
- GPT 5.2 Codex: 92.1%Top
- GPT 5.1 Codex: 83.0%
AA-LCR (unversioned)
Long-context reasoning, earlier grading
- GPT 5.2 Codex: 82.3%Top
- GPT 5.1 Codex: 69.3%
Scores from Artificial Analysis, updated Oct 26, 2026. GPT 5.2 Codex was tested at xhigh reasoning effort; compare scores measured at the same effort.Artificial Analysis
Developers
Use it through the API
Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.
curl https://www.noumen.xyz/api/v1/chat/completions \
-H "Authorization: Bearer $NOUMEN_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/gpt-5.2-codex",
"reasoning_effort": "medium",
"messages": [{ "role": "user", "content": "Explain this stack trace." }]
}'import os
from openai import OpenAI
client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
model="openai/gpt-5.2-codex",
messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)OpenAI
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