🚨 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: gqlquery 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:

lightning__AgentforceInput

lightning__AgentforceOutput

// 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)

Lightning Out 2.0 (Modern)

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 apexTests = discovery.getApexTests();

// Get Flow tests List 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

Resources Lightning Web Components Dev Guide Winter '26 Release Notes SLDS 2.0 Lightning Out 2.0