# Aggregated Change Signal Return

> Collapse multiple change sources into one caller-facing boolean so headless bootstraps know whether a downstream refresh is necessary.

- Skill: `vishuwa2004/aggregated-change-signal-return` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add vishuwa2004/aggregated-change-signal-return`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vishuwa2004/aggregated-change-signal-return/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: vishuwa2004 (https://skillmd.com/u/vishuwa2004)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/vishuwa2004/aggregated-change-signal-return

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# SKILL: Aggregated Change Signal Return
**Domain:** extensions-mcp  
**Trigger:** Apply when a headless setup flow can change state through several mechanisms but callers only need one final answer about whether they must refresh downstream registries.
**Source Pattern:** Distilled from reviewed extension lifecycle and source-reconciliation patterns.

## Core Method
Aggregate every state-changing branch inside the headless install flow into one caller-facing signal. Seed registration, marketplace reconciliation, and delisting can each materially change the runtime even if the others do nothing, so the function should accumulate them into a single boolean that tells the caller whether a follow-up refresh is required. This keeps the internal branching detailed while exposing a minimal external contract.

## Key Rules
- Initialize the change signal from the earliest state-changing step instead of only from the main reconcile path.
- Fold every later state mutation into the same signal, even if it comes from cleanup or enforcement rather than install.
- Keep the caller contract narrow: one signal that means "refresh downstream state now," not a grab bag of internal counters.
- Update the signal only on genuine state changes so callers do not refresh on no-op runs.

## Example Application
If a headless extension bootstrap registers seeds, installs missing registries, and removes delisted plugins, return one `extensionsChanged` boolean that becomes true if any of those paths modified the effective plugin set. The caller can then refresh command discovery once, regardless of which branch caused the change.

## Anti-Patterns (What NOT to do)
- Do not expose only install counts when cleanup or seed registration can also require a downstream refresh.
- Do not make callers reconstruct change state from several independent metrics when the callee already knows the full picture.