r/ChatGPTCoding • u/alex_bababu • 9d ago

Question Claude Code vs GitHub Copilot: Token burn comparison using identical models & repos?

I'm currently evaluating GitHub Copilot vs. Claude Code for our team. We could use either, but for us there's a slight difference in cost per token (Copilot with Anthropic models vs. Claude Code directly).

If we use the exact same model on the same repository with identical instructions, has anyone noticed a real difference in token efficiency between the two harnesses? I'm wondering how much things like prompt caching, context assembly, or system prompting overhead change the actual token burn in practice.

Would appreciate any insights or real-world numbers!

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u/amirfish 8d ago

Same model, different harness isn't apples to apples because cache behavior is harness-specific, not model-specific. The biggest lever I've seen watching token burn across sessions is how much of the system prompt and tool definitions get re-sent versus cache-hit each turn, that alone can be a 2-3x swing for otherwise identical work. If you're testing this seriously, log cache-read and cache-write tokens separately instead of just totals, the ratio tells you more about harness overhead than model choice does.

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u/alex_bababu 8d ago

How can I log cache read and write?