OpenAI o3 & GPT-4o — Reasoning Models, Install, Use-Cases & Cost (2026 Sync)

By Shakti Tiwari — AI practitioner, systems builder

Sync update. Not financial advice. Free help at optiontradingwithai.in.

1. OpenAI o3 + GPT-4o

OpenAI ships o3 (reasoning) + GPT-4o (fast). o3 thinks before answering — best for math/code/logic.

2. What Changed

• o3: deliberative reasoning
• 4o: multimodal, fast, cheap
• o3-mini: budget reasoning
• ChatGPT API unified

3. Install

npm install -g @openai/cli
export OPENAI_API_KEY=sk-...
openai chat --model o3 "prove this theorem"

4. New Use-Cases

1. Reasoning — o3 math
2. Fast chat — 4o
3. Vision — 4o image
4. Code — o3 solves
5. Fine-tune — 4o
6. Assistants — stateful
7. JSON — structured
8. Batch — cheap

5. CPI / Cost

Model	Input /1K	Output /1K
o3	$0.010	$0.040
o3-mini	$0.0011	$0.0044
GPT-4o	$0.005	$0.015

CPI: o3 5K reasoning + 2K out ≈ $0.13. 4o cheap.

6. vs Others

• Claude 4: code
• Gemini 2.5: context
• DeepSeek R1: cheap reasoning
• OpenAI: ecosystem

7. Local Integration

Hermes + OpenAI (research) + Ollama (private).

8. Cost Control

• 4o for bulk
• o3 only hard
• Cache + batch

9. Risks

• Key leak
• o3 cost

10. My Stack

Hermes + OpenAI (research) + Qwen3 (local).

FAQ

Q: Free?
A: Trial credit.

Q: o3 worth?
A: For hard logic.

Q: Advice?
A: Education.

About

Shakti Tiwari. Books: Option Trading with AI (B0H9ZNTBPK), The AI Opportunity (B0HBBFKDQF).

🌐 optiontradingwithai.in
📧 [e-mail]

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Disclaimer: Not financial advice.