Serena’s `replace_content`/edit path can reuse a stale cached file buffer after a file was modified outside the tool, causing writes to silently discard newer external changes (one reported case lost 388 lines).
Scattered source updates, isolated context, and manual follow-up across multiple feeds.
The primary technical fix is to prevent stale cached reads: before reusing a cached `LSPFileBuffer`, compare cached metadata (e.g., mtime/hash) with on-disk state and invalidate/reload the buffer so edit helpers always operate on current content.
Developers using Serena alongside other editors or Git in the same workspace can lose legitimate on-disk updates without any error—`replace_content` may write stale content and erase their latest changes—so teams should prioritize enabling/validating file-change invalidation and then monitor whether multi-tool edit workflows still produce silent overwrite incidents. The intended implementation is an `open_file()` guard that detects changed `mtime` and forces a fresh read before `replace_content` computes replacements, which reduces silent data-loss risk during MCP-based editing workflows.
Developers using Serena alongside other editors or Git in the same workspace can lose legitimate on-disk updates without any error—`replace_content` may write stale content and erase their latest changes—so teams should prioritize enabling/validating file-change invalidation and then monitor whether multi-tool edit workflows still produce silent overwrite incidents. The intended implementation is an `open_file()` guard that detects changed `mtime` and forces a fresh read before `replace_content` computes replacements, which reduces silent data-loss risk during MCP-based editing workflows.