Refactoring

---
name: refactoring
description: "Improve code structure while pinning and proving unchanged externally observable behavior."
disable-model-invocation: true
---

# Refactoring

## Child session handoff

Read [the handoff contract](../poteto-mode/references/subagent-handoff.md).
New tasks, repair rounds, retries, and queue items use fresh child sessions
with the original brief, every later directive, prior findings and responses,
and unresolved objections. Reuse only for required costly live state, and
only when the host allows it. Stop and fence active writers before replacement.
A host-owned orchestrator's model catalog, workspace binding, child tools,
and review-round rules take precedence over the native binding above.
Keep its task handles and attribution receipts. Do not use a backing child
conversation as a new delegated review, or claim native-record verification
for a host-owned child. Report attribution evidence gaps explicitly.

The root owns the behavior contract. Structure may change; behavior may not.

1. Use `how` to trace the affected behavior and callers. Pin the current
   contract with a characterization test, snapshot, equivalence harness, or
   recorded real-surface result before structural edits. Type checking alone is
   not a behavior pin.
2. Name the current reader-load problem and the target shape. The target should
   remove branches, invalid states, duplication, or needless layers rather than
   add speculative abstraction.
3. Remove dead code and redundant indirection before introducing the target
   structure. For an API reshape, migrate all in-scope callers and delete the
   obsolete path in the same verified wave.
4. Assign one bounded writer or implement at the root. A delegated writer uses
   the active `code.delegates` route when configured. Use isolation when
   available; otherwise serialize writes. Keep each step behavior-preserving and
   rerun the pin after each independently meaningful slice.
5. The root reviews the diff and runs an equivalence check on the real artifact.
   If behavior changes, split it into a separately requested feature or bug fix.
6. Keep the refactor only if the final code measurably lowers reader load.
7. Do not publish or open a pull request unless the user explicitly requested it.

Return the pinned contract, structural before and after, exact equivalence
proof, reader-load reduction, reverted experiments, and verification boundary.