Fix HUD context percentage to match /context across window sizes

[StephenJoshii]

Summary

Fixes #48

Fix context percentage mismatch between HUD and /context command for context windows larger than 200k tokens.

The autocompact buffer was hardcoded as 45000 tokens, which only worked correctly for 200k windows (45k = 22.5% of 200k). For larger windows (500k, 1M), the HUD showed significantly lower percentages than /context.

Changed the buffer from a fixed value to a dynamic 22.5% of the context window size:

// Before
export const AUTOCOMPACT_BUFFER = 45000;

// After
export const AUTOCOMPACT_BUFFER_PERCENT = 0.225;
const autocompactBuffer = size * AUTOCOMPACT_BUFFER_PERCENT;

Window | Before | After | /context
200k | 45% | 45% | 45%
500k | 23% | 36% | 36%
1M | 9% | 27% | 27%

Testing

• npm test
• npm run test:coverage

Checklist

• Tests updated or not needed
• Docs updated if behavior changed

[StephenJoshii]

simply changed the hardcoded 45000 buffer to a dynamic: windowSize * 0.225.

[jarrodwatts]

Thanks @StephenJoshii - but what claude models have context windows that are not 200k?

saw this issue raised once before but wasn't sure how people run into it

[StephenJoshii]

Larger enterprise/ preview models, or any setup where the context size is set differently. In those cases the hardcoded value stops matching the intended behavior.

[jarrodwatts]

Thank you for the percentage-based approach! This was incorporated into #55 - the buffer is now 22.5% of context window size instead of hardcoded 45k, so it scales correctly for enterprise windows.

Credit: Your idea of using a percentage instead of fixed tokens was key to the solution. 🙏