josiahsiegel 🚨 CRITICAL GUIDELINES
Windows File Path Requirements
MANDATORY: Always Use Backslashes on Windows for File Paths
When using Edit or Write tools on Windows, you MUST use backslashes (\) in file paths, NOT forward slashes (/).
Examples:
- ❌ WRONG:
D:/repos/project/file.tsx - ✅ CORRECT:
D:\repos\project\file.tsx
This applies to:
- Edit tool file_path parameter
- Write tool file_path parameter
- All file operations on Windows systems
Documentation Guidelines
NEVER create new documentation files unless explicitly requested by the user.
- Priority: Update existing README.md files rather than creating new documentation
- Repository cleanliness: Keep repository root clean - only README.md unless user requests otherwise
- Style: Documentation should be concise, direct, and professional - avoid AI-generated tone
- User preference: Only create additional .md files when user specifically asks for documentation
Lightning Web Components 2025 Features
lightning/graphql Module (Winter '26)
New module replaces deprecated lightning/uiGraphQLApi:
Migration
// ❌ Old (deprecated)
import { gql, graphql } from 'lightning/uiGraphQLApi';
// ✅ New (Winter '26)
import { gql, graphql } from 'lightning/graphql';
export default class MyComponent extends LightningElement {
@wire(graphql, {
query: gql`
query getAccount($id: ID!) {
uiapi {
query {
Account(where: { Id: { eq: $id } }) {
edges {
node {
Id
Name
Industry
}
}
}
}
}
}
`,
variables: '$variables'
})
results;
get variables() {
return { id: this.recordId };
}
}
Benefits
- Improved performance
- Better error handling
- Enhanced type safety
- Future-proof API
Local Development (sf lightning dev component)
Run LWC components locally without deploying:
# Start local dev server
sf lightning dev component
# Opens browser at http://localhost:3333
# Live reload on file changes
# No deployment needed
# Faster development cycle
# Specify component
sf lightning dev component -n myComponent
# Specify target org
sf lightning dev component -o myOrg@example.com
Benefits:
- Instant feedback (no deployment wait)
- Debug in real browser DevTools
- Hot module replacement
- Work offline
Platform Module Access in Component Preview
Access platform modules in single component preview:
// Works in local preview now
import { getRecord } from 'lightning/uiRecordApi';
import { ShowToastEvent } from 'lightning/platformShowToastEvent';
import { NavigationMixin } from 'lightning/navigation';
// Previously required full org deployment
// Now works in sf lightning dev component
Agentforce Targets (Winter '26)
New LWC targets for AI agents:
<!-- meta.xml -->
<targets>
<!-- Input component for Agentforce -->
<target>lightning__AgentforceInput</target>
<!-- Output component for Agentforce -->
<target>lightning__AgentforceOutput</target>
</targets>
// agentInputComponent.js
import { LightningElement, api } from 'lwc';
export default class AgentInputComponent extends LightningElement {
@api agentContext; // Provided by Agentforce
handleSubmit() {
const userInput = this.template.querySelector('input').value;
// Send to Agentforce
this.dispatchEvent(new CustomEvent('agentinput', {
detail: { input: userInput }
}));
}
}
Lightning Out 2.0 (GA Winter '26)
Re-imagined embedding with web components:
Traditional Lightning Out (Legacy)
<script src="https://MyDomain.lightning.force.com/lightning/lightning.out.js"></script>
<script>
$Lightning.use("c:myApp", function() {
$Lightning.createComponent("c:myComponent",
{ recordId: "001..." },
"lightningContainer",
function(cmp) { /* callback */ }
);
});
</script>
<div id="lightningContainer"></div>
Lightning Out 2.0 (Modern)
<!-- Standards-based web components -->
<script src="https://MyDomain.lightning.force.com/c/myComponent.js" type="module"></script>
<!-- Use as web component -->
<c-my-component record-id="001..." ></c-my-component>
<!-- No Aura dependency -->
<!-- Powered by LWR (Lightning Web Runtime) -->
<!-- Lighter and faster -->
Benefits:
- 50-70% smaller bundle size
- Faster load times
- Standards-based (no proprietary framework)
- Better browser compatibility
- Simplified integration
SLDS 2.0 with Dark Mode (GA Winter '26)
Salesforce Lightning Design System 2.0:
/* Dark mode support in custom themes */
:host([data-theme="dark"]) {
--lwc-colorBackground: #16325c;
--lwc-colorTextPrimary: #ffffff;
--lwc-brandPrimary: #1589ee;
}
/* Light mode */
:host([data-theme="light"]) {
--lwc-colorBackground: #ffffff;
--lwc-colorTextPrimary: #181818;
--lwc-brandPrimary: #0176d3;
}
// Toggle dark mode
export default class ThemeToggle extends LightningElement {
handleThemeChange(event) {
const theme = event.target.checked ? 'dark' : 'light';
this.template.host.setAttribute('data-theme', theme);
}
}
SLDS Linter with Fix Option
# Install SLDS linter
npm install -D @salesforce-ux/slds-linter
# Lint with auto-fix
npx slds-linter --fix src/
# CI/CD integration
npx slds-linter src/ --format json > slds-report.json
Unified Testing APIs (Winter '26)
Test Discovery and Test Runner APIs unify Apex and Flow testing:
// Discover all tests
Test.DiscoveryResult discovery = Test.discoverTests();
// Get Apex tests
List<Test.ApexTestInfo> apexTests = discovery.getApexTests();
// Get Flow tests
List<Test.FlowTestInfo> flowTests = discovery.getFlowTests();
// Run all tests from single location
Test.RunResult result = Test.runTests(discovery);
// Check results
System.debug('Apex passed: ' + result.getApexTestsPassed());
System.debug('Flow passed: ' + result.getFlowTestsPassed());
Benefits:
- Unified test execution
- Single test report
- Simplified CI/CD
- Better test orchestration
Lightning Web Security Enhancements
New security protections with API distortions:
// Additional secure protections automatically applied
export default class SecureComponent extends LightningElement {
connectedCallback() {
// Web APIs now include security distortions
// ESLint rules validate distortion compliance
// Example: Secure window access
const secureWindow = window; // LWS-secured reference
}
}
ESLint Rules for Security
// .eslintrc.json
{
"extends": ["@salesforce/eslint-config-lwc/recommended"],
"rules": {
"@lwc/lwc/no-inner-html": "error",
"@lwc/lwc/no-document-query": "error",
"@salesforce/lwc-security/no-unsafe-references": "error"
}
}
Practical Migration Examples
GraphQL Module Update
// Before (Winter '25)
import { gql, graphql } from 'lightning/uiGraphQLApi';
@wire(graphql, { query: gql`...` })
results;
// After (Winter '26)
import { gql, graphql } from 'lightning/graphql';
@wire(graphql, { query: gql`...` })
results;
Local Development Workflow
# Old workflow (deploy every change)
sf project deploy start
# Wait 30-60 seconds
# Test in org
# Repeat...
# New workflow (instant feedback)
sf lightning dev component
# Changes reflect immediately
# No deployment
# Test in local browser
# Deploy only when ready
Embedding with Lightning Out 2.0
<!-- Old (Lightning Out 1.0) -->
<script src="/lightning/lightning.out.js"></script>
<script>
$Lightning.use("c:app", function() {
$Lightning.createComponent("c:comp", {}, "div", callback);
});
</script>
<!-- New (Lightning Out 2.0) -->
<script src="/c/comp.js" type="module"></script>
<c-comp></c-comp>