---
description: Core project conventions for the Outlook MCP server
alwaysApply: true
---
# Core Conventions
- Use CommonJS (`require` / `module.exports`) in plain JavaScript; do not use ESM.
- Keep shared constants in `config.js`; avoid hard-coded field lists, pagination, URLs, and timezone values.
- Build MCP responses with `makeResponse()` and `makeErrorResponse()` from `utils/response-helpers.js`.
- Detect auth failures with `isAuthError(error)` and return the auth message directly.
- For data output, call `formatResponse(structuredData, textFallback)` from `utils/response-formatter.js`.
- Log diagnostics with `console.error()` (stdout is reserved for MCP protocol traffic).
## Baseline Error Pattern
```js
try {
// handler logic
} catch (error) {
if (isAuthError(error)) {
return makeErrorResponse(error.message);
}
return makeErrorResponse(`Error doing X: ${error.message}`);
}
```
