Comparing Gemini 3.1 and ChatGPT 5.2: A Practical Guide to Choosing Based on Reasoning, Writing, and Development Workflows — Both Gemini 3.1 especially 3.1

Both Gemini 3.1 (especially 3.1 Pro) and ChatGPT 5.2 (GPT-5.2) are said to have “strong reasoning capabilities” and to be “fast at research and writing,” but when it comes to actually paying for them and incorporating them into your daily workflow, it’s easy to feel unsure.

Based on primary sources such as official blogs, release notes, pricing pages, and API documentation, we’ll compare Gemini 3.1 Pro and GPT-5.2 in terms of reasoning, long-form writing, development, and blog creation.

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Comparison Premises

Gemini 3.1 Pro

• Announced on the official Google blog on February 19, 2026
• Explicitly states “ARC-AGI-2 verified at 77.1%”
• Offered as “Gemini 3.1 Pro Preview” on the Gemini API

References:

• Google Official Blog (February 19, 2026)
• Gemini API Official Changelog

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ChatGPT 5.2 (GPT-5.2)

• Released on December 11, 2025, on the OpenAI Official Blog
• Listed as 55.6% on SWE-Bench Pro (Verified 80%)
• Knowledge cutoff: August 2025 (as stated in official release notes)

References:

• OpenAI Official Blog (December 11, 2025)
• ChatGPT Official Release Notes
• OpenAI API Official Model Page

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Comparison of Inference Performance

Features of Gemini 3.1 Pro

• Strongly emphasizes improvements in inference benchmarks
• ARC-AGI-2: 77.1% verified
• Officially described as a “smarter baseline”

Advantages:

• Officially clear improvements in complex problem-solving
• Strong integration with development tools (CLI / Android Studio)

Points to Note:

• It is explicitly stated that this is a preview release

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Features of GPT-5.2

• Emphasis on practical and coding evaluations
• SWE-Bench Pro scores explicitly stated
• Highlights improvements in long-text reasoning and factual accuracy

Advantages:

• Long-text integration capabilities officially mentioned
• Clear API specifications make it easy to use

Points to Note:

• Officially states that verification is required for critical use cases

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Differences in Long-Form and Blog Writing

Gemini 3.1 Pro

• Gemini app
• NotebookLM
• Integration with Deep Research

Advantages:

• Easy to establish a workflow of research → organization → drafting

Disadvantages:

• May experience inconsistencies due to being in the preview phase

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GPT-5.2

• Integration with long-form documents
• High context processing capability (400,000 tokens)
• Knowledge cutoff: August 2025

Advantages:

• Stable editing and restructuring
• Well-suited for improving the quality of final blog drafts

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Coding Comparison

Gemini 3.1 Pro

• Gemini CLI
• Android Studio
• Google Antigravity
• Vertex AI

A workflow that excels in IDE integration and agent design.

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GPT-5.2

• Clear API specifications
• reasoning.effort setting
• SWE-Bench Pro evaluation

Designed for practical code assistance.

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Pricing Comparison (Based on Official Information)

Gemini

• Google AI Pro: 2,900 yen/month (includes 1-month free trial)
• Google AI Ultra: 36,400 yen/month (discount periods available)

ChatGPT

• Free / Go / Plus / Pro / Business / Enterprise
• GPT-5.2 available on Plus and higher plans
• Prices may vary depending on display conditions

*Please refer to the official website for the latest information

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Recommendations by Use Case

Blog-Focused

• Emphasis on editing long-form text → GPT-5.2
• Research-focused → Gemini 3.1 Pro

Development-Focused

• Prioritize CLI / IDE integration → Gemini
• Prioritize API clarity and real-world stability → GPT-5.2

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Conclusion

• Gemini 3.1 Pro’s strengths lie in enhanced inference benchmarks and integration with the Google ecosystem.
• GPT-5.2 excels in practical stability, long-form integration, and clear coding evaluations.

The most reliable approach is:

Use Gemini for research
→ Use GPT-5.2 for structuring and polishing

This division of labor minimizes overlap and ensures highly reproducible results.

Primary source checked

• blog.google