Add a "Bad Patterns" Section to CLAUDE.md

Telling Claude what to build only gets you halfway there. The real productivity unlock is also telling it what you never want to see.

Add a ## Bad Patterns section to your CLAUDE.md with concrete code examples you always reject:

## Bad Patterns

Never do these:
- Don't use `any` in TypeScript without a type guard
- Never import from `src/legacy/utils` -- use `src/utils` instead
- Don't use raw SQL strings -- always use the query builder
- Never define business logic inside a controller
- Don't use `console.log` for error handling -- use the logger service

Claude reads CLAUDE.md at the start of every session, so it absorbs your no-go list before writing a single line. One developer reported dropping their suggestion rejection rate from around 40% to around 10% after adding this section -- same model, far fewer back-and-forth corrections.

The existing ## Rules or ## Guidelines sections tell Claude what to aim for. A dedicated ## Bad Patterns section tells it what to avoid entirely. Together they create a much tighter feedback loop than prompting alone.

The more specific the example, the stronger the rule. Vague guidance gets vague compliance.

Positive rules set the target -- negative rules remove the misses.

via @gagansaluja08