shared-runtime-safe-changes

name	shared-runtime-safe-changes
description	Safely modify shared runtime layers (`packages/lwc/main/*`, `packages/lwc/extension/*`, `packages/lwc/shared/*`) without regressing either core extension (`packages/extension/*`) or chat extension (`packages/extension-chat/*`).

Shared Runtime Safe Changes

Use this skill when a request touches shared code consumed by multiple targets.

Goal

Ship shared-runtime changes with explicit guardrails and cross-target verification.

When to trigger

Trigger if any changed file is under:

• packages/lwc/main/*
• packages/lwc/extension/*
• packages/lwc/shared/*

Especially when changing:

• shared components used by both targets
• connector/store/agent runtime behavior
• sidepanel-related shared UI/logic

Risk model

Shared edits can silently break one target while another still passes.

• Core extension target: packages/extension/*
• Chat extension target: packages/extension-chat/*

Never assume target parity without running both target builds after shared edits.

Golden rules

1. Keep defaults backward compatible.
2. Prefer explicit feature flags for target-specific behavior.
3. Avoid hard-coding chat/core assumptions into shared modules.
4. Keep diffs minimal and scoped to the request.

Guardrail patterns

Target-specific behavior in shared UI

• Add API flags with safe defaults:
  • @api useInlineOnboarding = false
  • @api hideLlmSettingsCard = false
• Enable only in the consuming target template.

Runtime sidepanel behavior

• chrome.sidePanel.open() should stay in user-gesture paths only (action/command).
• Avoid open() in generic runtime message handlers unless gesture is guaranteed.

Shared state/config

• Avoid global behavior changes unless requested.
• Prefer additive changes over replacing existing semantics.

Required verification matrix

Run these after shared-runtime edits:

1. Targeted lint/format:

npx eslint <changed .js/.ts files>
npx prettier --check <changed .html/.css/.js/.ts files>

2. Core extension regression:

npm run build:extension:main

3. Chat extension regression:

npm run build:extension:chat:main

4. If relevant to shared manifests/registry:

npm run build:shared

Reporting format

Always report:

• Shared files touched
• Target-specific guardrails added (if any)
• Commands run and pass/fail
• Residual risk (if tests/builds are partially unavailable)

Out of scope

• Chat-only changes fully isolated to packages/extension-chat/* (use chat-extension-safe-changes)
• Core-only changes fully isolated to packages/extension/* (use core-extension-safe-changes)