[Bug] Agent loses session context after /compact, conflates own edits with pre-existing code

Bug Description
Title: Simple UI tweaks spiraled into a long broken detour; agent lost
session continuity and over-engineered

Model: Claude Opus 4.8 (1M context), Claude Code CLI

What I asked for: A handful of small timeline-UI tweaks. The key one: make
two small mute/solo buttons look the same but have a bigger click area. Plus
fix an option-click behavior. Trivial stuff.

What happened: It took an enormous number of turns, broke working things, and
I had to repeatedly drag it back on course. Ended up telling it to just
revert.

Failure modes (blunt):

1. Over-engineering. A "bigger click area" ask became a margin hack →

transparent "halo" widget → vertically-stretched buttons. Three wrong designs
before reverting. Should have been a few lines or an early "I can't do
exactly that, here are the options."

1. Compaction amnesia. After a /compact, it treated its own earlier-session

edits as "pre-existing / someone else's work" (because git showed them
committed), and reasoned from that wrong premise. It could not keep track of
what it had itself done across the compaction. "It's almost like compact and
new are the same thing."

1. Blame-deflecting. Instead of just fixing, it spent effort arguing what was

"pre-existing" vs its own change — exactly the wrong instinct.

1. Overconfident + wrong, repeatedly. Asserted "the margin area stays

clickable" (false in Qt), then "the halo fixes it with no artifacts" (it
caused graphic artifacts). Each confident claim cost another round-trip.

1. Theorizing instead of looking. Declared fixes done without verifying

against the actual running editor; only checked reality after I pushed back.
Even screenshotted the wrong window.

1. Ignored the actual constraint. I said "not wider" and "look the same"; it

made them wider, then taller — substituting its own interpretation for what I
asked.

Net: small cosmetic tweaks, lots of wasted time and tokens, working features
broken mid-stream, and the desired outcome ultimately not delivered (reverted
to original).

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.185
• Feedback ID: 6a20a120-b6da-417d-a5c6-79826cbfcce6

Errors

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