GitHub Copilot Model Context Sizes (Nov 2025)

Dr. Furqan Ullah — Thu, 13 Nov 2025 03:14:55 +0000

Main Models
GPT-4.1 — 128,000 tokens
GPT-5 mini — 128,000 tokens
GPT-5 — 128,000 tokens
GPT-4o — 128,000 tokens
o3-mini — 200,000 tokens
Claude Sonnet 3.5 — 90,000 tokens
Claude Sonnet 3.7 — 200,000 tokens
Claude Sonnet 4 — 128,000 tokens
Claude Sonnet 4.5 — 200,000 tokens (standard) / 1,000,000 tokens (beta)
Gemini 2.0 Flash — 1,000,000 tokens
Gemini 2.5 Pro — 128,000 tokens
o4-mini — 128,000 (picker) / 200,000 (full version)
Grok Code Fast 1 — 128,000 tokens

Smaller Models
GPT-3.5 Turbo — 16,384 tokens
GPT-4 — 32,768 tokens
GPT-4 Turbo — 128,000 tokens
GPT-4o mini — 128,000 tokens

💡 How big is that, really?

Let’s take Claude Sonnet 4.5 with a 200,000-token context window.
If one C++ or JavaScript file has ~2,000 lines and each line averages ≈ 15 tokens (including code, spaces, and comments), → one file ≈ 30,000 tokens.

That means Claude Sonnet 4.5 can process around 6 full files of 2,000 lines each at once. If you’re using the 1,000,000-token extended version, that jumps to ~33 files.

🧠 Conclusion

So next time your AI assistant suddenly “forgets” what was said earlier or mixes details halfway through your project, remember — it’s not confused… it’s simply “lost in the middle.”
Once that context window fills up, older information fades away to make room for new input.

👉 Now you know why the “lost in the middle” problem happens — because even AI can only remember so much at once.

Forem: Dr. Furqan Ullah

GitHub Copilot Model Context Sizes (Nov 2025)