[Bug] Edit/Write operations store full file content per edit, causing transcript bloat and resume hang on large files #78592

Bug Description
Title: Edit/Write stores full file content per edit → multi-MB files bloat transcript and freeze "Resuming conversation…"

What happens: Each Edit/Write call records the entire before+after file content in the transcript's toolUseResult field. Editing a 5.4 MB file writes ~5.4 MB per edit regardless of change size. Seven edits produced an 80 MB .jsonl; resume then hangs on "Resuming conversation…" indefinitely.

Repro: Edit a >5 MB text file ~7 times in one session → quit → resume. It never loads.

Impact: Session appears unrecoverable. Manual fix required: trim oversized toolUseResult lines from the .jsonl (80 MB → 965 KB restored resume).

Comparison: Codex edits the same file 150× with no freeze — its apply_patch records only the diff hunk (max transcript line 331 KB vs. Claude Code's ~11.8 MB/line).

Suggested fix: Store a diff/patch in toolUseResult for large files instead of full snapshots, or cap/externalize snapshots above a size threshold.

Environment Info

• Platform: linux
• Terminal: vte-based
• Version: 2.1.211
• Feedback ID: c86c2dbf-a21a-463e-addc-59ff3173c4c6

Errors

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