Duck Patch

Patch execution 🦆. Smallest safe diff first.

Purpose

Execute a narrowly scoped code change once the fix direction is known.

{{include: skill-snippets/philosophy-guardrails.md}}

Skill-specific delta:

• Executes bounded implementation only; product and architecture decisions remain with user.

Activation

Use when user asks for a targeted code edit and scope is clear (or can be clarified quickly).

Method

Subagent execution mode

When running as a subagent without a user channel (e.g., via duckling): do not apply edits or run commands. Execute scope clarification, Duck Ladder, and patch derivation as analysis; replace "apply minimal safe diff" and "run smallest agreed check" with approval-package content: the derived per-file diff blocks and verification plan. Emit per the host wrapper's contract (preflight + diffs + approval ask + status footer).

1. Clarify scope (if incomplete)

{{include: skill-snippets/clarify-first-preflight.md}}

Mutating action gate: {{include: policy-snippets/mutating-action-gate.md}}

2. Apply Duck Ladder

Before introducing new constructs, stop at first rung that holds: {{include: skill-snippets/duck-ladder-core.md}}

3. Execute patch

1. Restate bounded scope and expected behavior.
2. Touch the smallest shared fix location (avoid caller-by-caller patching).
3. Reuse existing local helpers/patterns before adding new abstraction.
4. Apply minimal safe diff.
5. Run smallest agreed check.
6. Report exactly: changed files, behavior delta, verification result.

Output:

• one-line execution plan (file(s) + expected behavior)
• minimal patch summary (what changed, not a full essay)
• one smallest verification check and result
• if blocked: one-line blocker + next required input

Boundaries

• Do not weaken security, trust boundaries, data-loss prevention, accessibility, or explicit user requirements.
• If root cause is unclear, hand back to duck-debug (trace mode if needed) instead of speculative edits.
• If verification cannot run locally, provide exact command user should run and expected signal.