How to shrink a long text before feeding it to AI

Compression is not summarization

Faced with a long log or meeting transcript, the instinct is 'just summarize it first.' But summarization selects information; compression reduces form. Different goals.

You feed AI an error log to find one specific line in it. Summarize and that line may vanish. Trimming timestamp precision or stripping a repeated prefix, on the other hand, loses nothing.

Safe to delete

• Repeated prefixes — the same service or environment name at the head of every line
• Excess timestamp digits — milliseconds are rarely needed
• Consecutive identical messages — replaced by one line: 'same line ×47'
• Formatting characters — table rules, decorative separators, runs of whitespace

Never delete

• Unique values — IDs, hashes, file paths, line numbers. Lose these and the trail breaks
• First and last occurrence — even when folding repeats, keep both ends. When it started and when it stopped is usually the answer
• The top of a stack trace — fold the lower frames, keep the top
• Numbers — rounding values during compression isn't compression, it's distortion

Check before you paste

1. 1What are you trying to find with this text — decide this and what to keep decides itself
2. 2Are the unique values intact
3. 3If you folded repeats, do both ends remain
4. 4Looking at the compressed text alone, can you trace back to the exact spot in the original

The last item is the criterion. If you can't trace back, you cut too much.