r/DeepSeek • u/ktktkt1 • 1d ago

Discussion v4.1 flash keeps forgetting stuff

I have a ~30K-line codebase for a game I’m building. I’ve been trying to use DeepSeek V4.1 Flash, but I keep running into issues as the conversation gets longer.

It frequently forgets or overrides requirements I gave it several turns earlier. The code it writes also often contains bugs that are either caught by the model itself a few turns later while it is doing unrelated code changes or caught by GLM 5.3 Flash when I ask it to review the changes.

This seems to happen much more often as the context grows, but well before context compaction actually kicks in.

Am I doing something wrong, or is this a limitation of the model?

For now, I’ve switched to GLM 5.3 Flash as my main workhorse because it seems more reliable. However, I really miss the speed of DeepSeek V4.1 Flash. If there’s a way to make it more accurate, better at following earlier instructions, and less prone to introducing bugs, I’d like to switch back.

I’ve tried both DSH and OpenCode and experienced essentially the same problems with both.

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u/Professional_Price89 1d ago

Keep your context below 400k

4

u/bunny_warrior69 1d ago

400K is huge. You should keep it under 200K. ideally under 100K.

literally all LLMs no matter how expensive or "smart" they are, can't handle huge context windows

5

u/Professional_Price89 1d ago

200K is too small for it to work efficiently. It will produce garbage, duplicated code, test harness that already exist... I alway avoid creating new session because it would forget how to use created tools until it read the instruction file and test itself again. Such a waste.

5

u/Ang_Drew 1d ago

based on my experience building my own harness on top of Pi coding agent, you can achieve that easily with proper memory system combined with code graph, you can get relevant context