For db just give it credentials of a readonly user, for instructions you can do this.
You can give setup a list of approved tools and bash commands
https://www.anthropic.com/engineering/claude-code-best-pract...
Also, people shouldn't be running any LLM on data of a business without a proper contract in place like you have with any vendor who has access to your data. And if there's specific PII requirements, those should be covered too.