Add ESLint configuration with TypeScript support for code quality enforcement

.eslintignore

@@ -0,0 +1,8 @@
+node_modules/
+dist/
+.git/
+*.log
+.env
+.env.*
+chart/
+src/shared/

.eslintrc.mjs

@@ -0,0 +1,84 @@
+import tsParser from '@typescript-eslint/parser';
+import tsPlugin from '@typescript-eslint/eslint-plugin';
+import importPlugin from 'eslint-plugin-import';
+
+export default [
+  {
+    files: ['**/*.ts', '**/*.js', '**/*.mjs'],
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'module',
+      parser: tsParser,
+      parserOptions: {
+        project: './tsconfig.json',
+      },
+    },
+    plugins: {
+      '@typescript-eslint': tsPlugin,
+      'import': importPlugin,
+    },
+    rules: {
+      // TypeScript specific rules
+      '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
+      '@typescript-eslint/no-explicit-any': 'warn',
+      '@typescript-eslint/explicit-function-return-type': 'off',
+      '@typescript-eslint/explicit-module-boundary-types': 'off',
+      '@typescript-eslint/no-inferrable-types': 'error',
+      '@typescript-eslint/prefer-const': 'error',
+      '@typescript-eslint/no-var-requires': 'error',
+
+      // Import/Export rules
+      'import/order': [
+        'error',
+        {
+          groups: [
+            'builtin',
+            'external',
+            'internal',
+            'parent',
+            'sibling',
+            'index',
+          ],
+          'newlines-between': 'never',
+        },
+      ],
+      'import/extensions': [
+        'error',
+        'ignorePackages',
+        {
+          js: 'always',
+          ts: 'never',
+        },
+      ],
+
+      // General JavaScript rules
+      'no-console': 'off', // Allow console for logging in MCP server
+      'no-unused-vars': 'off', // Use TypeScript version instead
+      'prefer-const': 'error',
+      'no-var': 'error',
+      'object-shorthand': 'error',
+      'prefer-arrow-callback': 'error',
+      'arrow-spacing': 'error',
+      'prefer-template': 'error',
+
+      // Async/await preferences (per CLAUDE.md)
+      'prefer-promise-reject-errors': 'error',
+      'no-return-await': 'error',
+
+      // Naming conventions (per CLAUDE.md)
+      'camelcase': ['error', { properties: 'always' }],
+
+      // Code style (handled by Prettier, but some logical rules)
+      'eqeqeq': ['error', 'always'],
+      'curly': ['error', 'all'],
+      'brace-style': ['error', '1tbs'],
+    },
+  },
+  {
+    files: ['**/*.js', '**/*.mjs'],
+    rules: {
+      // Disable TypeScript-specific rules for JS files
+      '@typescript-eslint/no-var-requires': 'off',
+    },
+  },
+];

.gitignore

@@ -1,3 +1,4 @@
 dist
 node_modules
-.env
+.env
+.eslintcache

CLAUDE.md

@@ -6,6 +6,9 @@
 - Watch mode: `npm run watch` - Watches for changes and rebuilds automatically
 - Run server: `npm run start` - Starts the MCP server using stdio transport
 - Prepare release: `npm run prepare` - Builds the project for publishing
+- Lint: `npm run lint` - Runs ESLint to check code quality
+- Lint Fix: `npm run lint:fix` - Runs ESLint with automatic fixing
+- Lint Check: `npm run lint:check` - Runs ESLint with zero warnings allowed
 
 ## Code Style Guidelines
 
@@ -19,3 +22,15 @@
 - Follow camelCase for variables/functions, PascalCase for types/classes, UPPER_CASE for constants
 - Handle errors with try/catch blocks and provide clear error messages
 - Use consistent indentation (2 spaces) and trailing commas in multi-line objects
+
+## Linting
+
+This project uses ESLint for code linting with TypeScript support. The configuration enforces:
+
+- TypeScript best practices and type safety
+- Import/export ordering and module resolution
+- Async/await patterns over promises
+- Consistent naming conventions
+- Integration with Prettier for formatting
+
+ESLint is configured to work with the project's ES module setup and `.js` extension requirements for imports.

package.json

@@ -19,7 +19,10 @@
     "watch:http": "tsx watch src/index.ts http",
     "start": "node dist/index.js stdio",
     "start:http": "node dist/index.js http",
-    "inspector": "npx @modelcontextprotocol/inspector"
+    "inspector": "npx @modelcontextprotocol/inspector",
+    "lint": "eslint src --ext .ts,.js,.mjs",
+    "lint:fix": "eslint src --ext .ts,.js,.mjs --fix",
+    "lint:check": "eslint src --ext .ts,.js,.mjs --max-warnings 0"
   },
   "dependencies": {
     "@linear/sdk": "^56.0.0",
@@ -43,7 +46,11 @@
   "devDependencies": {
     "@types/express": "^5.0.3",
     "@types/node": "^22.16.4",
+    "@typescript-eslint/eslint-plugin": "^8.8.0",
+    "@typescript-eslint/parser": "^8.8.0",
     "ai": "^5.0.17",
+    "eslint": "^9.12.0",
+    "eslint-plugin-import": "^2.31.0",
     "prettier": "^3.6.2",
     "shx": "^0.4.0",
     "tsx": "^4.20.4",