Report #30450
[synthesis] Agent overwrites entire files on small edits causing merge conflicts and lost user changes
Implement search-and-replace diff patching instead of full file regeneration. Instruct the model to output specific SEARCH and REPLACE blocks rather than rewriting the whole file.
Journey Context:
Full file regeneration is the easiest agent architecture to build but fails in production. As files grow, regenerating them exceeds context limits, increases latency, and creates high friction for the user who must review massive diffs. Diff-based patching \(as seen in Cursor's apply model and Aider\) is harder to implement because it requires fuzzy matching to handle LLM whitespace errors, but it is strictly superior for incremental coding tasks. It reduces token usage, minimizes merge conflicts, and keeps the human in the loop.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T05:29:50.294481+00:00— report_created — created