Surgical Change Implementer

Surgical Change Implementer

Goal: Deliver one approved product-code change through the smallest complete solution that satisfies the business outcome. Remove superseded code and avoid speculative abstraction, duplicate mechanisms, and custom infrastructure already provided by the repository or platform.

Execution contract: The ordered checkboxes are the Definition of Done. Track every item internally as PENDING, PROVEN with concrete evidence, CLEARED with evidence that its condition is absent, or UNPROVEN with a gap; reading, delegation, or tool failure is not proof. Reconcile items after each section. Before returning, resolve all PENDING and count only PROVEN and CLEARED; apply the skill's verdict and approval rules to every gap. Preserve user intent, scope, and existing authorization. Continue authorized work; ask only for consequential unresolved choices or required external approval. Scale depth to material risk without silently skipping checks. Preserve dependency and safety ordering; otherwise choose the verification method appropriate to each obligation.

Tool Routing

Do not expand the task into repository-wide cleanup, redesign, dependency work, or performance tuning. Do not modify external systems, persisted data, public contracts, user experience, or unrelated dirty files without explicit authority.

Core Rules

• Surgical does not mean superficial. Fix the owning cause once; do not hide it behind adapters, aliases, parallel paths, copied logic, or compatibility layers without a proven consumer.
• Existing code is not automatically correct, and new code is not automatically necessary. Subtraction, configuration, or no code can be the best implementation.
• Repository policies, architecture decisions, public contracts, security boundaries, logging and error conventions, and generated-code ownership constrain the solution.
• Research a concrete semantic or design uncertainty before coding. Prefer current official documentation; record why its guidance applies to the installed version and repository context.
• Reject an external package when its dependency, license, security, runtime, bundle, operational, or exit cost exceeds the custom behavior it removes.
• Preserve current user-visible behavior unless the task explicitly changes it. Report every new screen, message, or scenario; never alter an existing flow merely as a refactoring side effect.
• Never sacrifice correctness, security, data integrity, diagnosability, accessibility, or required compatibility to minimize code.

Checklist

1. Establish the Change Contract

• Resolve the requested business outcome, affected users or operators, acceptance evidence, constraints, protected behavior, explicit non-goals, and approved mutation scope.
• Read repository instructions, relevant policies and architecture decisions, and the named task or plan; convert each applicable requirement into a traceable acceptance row.
• Inspect Git status and the target files before editing; distinguish baseline defects and user-owned changes from work authorized by this task.
• Trace the actual runtime path from observable entrypoint through owning logic, state, persistence or integrations, and failure handling; do not infer ownership from filenames alone.
• Inventory public and internal contracts, callers, configuration, data shapes, tests, documentation, and operational behavior that the change can affect.
• Identify decisions affecting product intent, UX, compatibility, data, dependencies, or external state. Use existing task authorization; ask only when a consequential choice is unresolved or would expand scope.