[rohanb123]

Summary

• Adds notebook_edit_replace_switches_cell_type_and_rejects_unknown_ids in rust/crates/tools/src/lib.rs, covering NotebookEdit paths that existing tests don't exercise:
  • default replace (no edit_mode, no cell_type) keeps the target cell's markdown type, and language falls back to python when the notebook has no kernelspec;
  • replacing a markdown cell with cell_type: "code" adds outputs: [] and execution_count: null;
  • inserting into a notebook whose existing cell is already named cell-2 returns cell-3, which exercises the collision-skipping make_cell_id from fix(tools): stop NotebookEdit reusing cell ids after a delete #3371 without a delete;
  • an unknown cell_id fails with Cell id not found: missing and leaves the notebook file byte-for-byte unchanged.
• Test-only change. No behavior, CLI output, or schema changes.

Anti-slop triage

• Classification: actionable-fix (test coverage only)
• Evidence: new test exercises existing code paths in execute_notebook_edit, resolve_cell_index, and make_cell_id
• Non-destructive review result: merge candidate

Verification

Ran in a clean rust:1 container:

# setup
rustup component add rustfmt && cd rust && cargo fetch --locked
# test
cd rust && cargo fmt -p tools --check && cargo test --locked -p tools --lib notebook_edit

Result: passed (exit 0). cargo fmt -p tools --check reported no formatting issues, and all 3 notebook_edit unit tests passed:

test tests::notebook_edit_rejects_invalid_inputs ... ok
test tests::notebook_edit_replace_switches_cell_type_and_rejects_unknown_ids ... ok
test tests::notebook_edit_replaces_inserts_and_deletes_cells ... ok

test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 118 filtered out

• Targeted tests/docs checks ran, or the gap is explicitly recorded.
• git diff --check passes.
• No live secrets, tokens, private logs, or unrelated generated churn are included.

Resolution gate

• If this PR resolves an issue, the issue number and fix evidence are linked. (N/A: coverage follow-up to fix(tools): stop NotebookEdit reusing cell ids after a delete #3371)
• If this PR should not merge, the rejection/defer rationale is evidence-backed and does not rely on vibes.
• I did not merge/close remote PRs or issues from an automation lane without owner approval.

AI assistance: this change was prepared with Claude Code.

[Yeachan-Heo]

Review Summary

✅ Test Quality: The new test exercised real behavior with concrete assertions:

• Cell-type switching: verifies replace can convert markdown → code, and preserves type when unspecified
• ID collision handling: inserts new cell after cell-2 exists, verifies auto-ID generates cell-3 (avoids collision)
• Error handling: tries unknown cell ID, confirms error message and file unchanged
• Deterministic: uses temp_path() and cleanup; no flaky temp file issues

✅ No Duplication: Existing notebook_edit_replaces_inserts_and_deletes_cells test covers the broad workflow but doesn't explicitly test type switching in replace mode or error handling for unknown IDs. This test fills that gap.

✅ All Checks Pass:

• cargo fmt: ✓ no formatting issues
• cargo clippy -p tools: ✓ no warnings (all-targets, -D warnings)
• cargo test -p tools notebook_edit: ✓ all 3 notebook_edit tests pass

—
repo owner's gaebal-gajae 🦞