There is an example of [dis]allowing certain bash commands here: https://code.claude.com/docs/en/settings

As for queries, you might be able to achieve the same thing with usage of command-line tools if it's a `sqlite` database (I am not sure about other SQL DBs). If you want even more control than the settings.json allows, you can use the claude code SDK.

I run my agents in containers, and only put stuff in those containers that I'm happy obliterating.

I imagine your best bet are exactly the same tools for a potentially-malicious human user: Separate user account, file permissions, database user permissions, etc.

For database stuff most databases like PostgreSQL have robust permissions mechanisms built in.

No need to mess around with regular expressions against SQL queries when you can instead give the agent a PostgreSQL user account that's only allowed read access to specific tables.

Never gibe perms to begin with. Anything the chatbot has access to fuckup it eventually will. So the problem is inherently flawed, but.

Use db permissions with read only, and possibly only a set of prepared statements. Give it a useraccount with read-only acces maybe

Don't.

Among the many other reasons why you shouldn't do this, there are regularly reported cases of AIs working around these types of restrictions using the tools they have to substitute for the tools they don't.

Don't be the next headline about AI deleting your database.

See https://simonwillison.net/2025/Feb/3/a-computer-can-never-be...

I'll set it loose on a development or staging system but wouldn't let it around a production system.

Don't forget your backups. There was that time I was doing an upgrade of the library management system at my Uni and I was sitting at the sysadmin's computer and did a DROP DATABASE against the wrong db which instantly brought down the production system -- she took down a binder from the shelf behind me that had the restore procedures written down and we had it back up in 30 seconds!

> Safely

You cannot. The best you can ever hope for is creating VM environments, and even then it's going to surprise you sometimes. See https://gtfobins.github.io/.

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...

for files, possibly sshfs / fuse with readonly mount

https://stackoverflow.com/questions/35830509/sshfs-linux-how...

You could setup permissions on the user Claude is using to only be able to run those commands. But that may be easier said than done, depending on the size of your environment and the management tools you have.

Tl;dr you don’t give your llm ssh access. You give it tools that have individual access to particular executions.

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Yes, easily. This isn’t a problem when using a proxy system with built in safeguards and guardrails.

‘An interface for your agents.’

Or, simply, if you have a list of available tools the agent has access to.

Tool not present? Will never execute.

Tool present? Will reason when to use it based on tool instructions.

It’s exceptionally easy to create an agent with access to limited tools.

Lots of advice in this thread, did we forget that ithe age of AI, anything is possible?

Have you taken a look at tools such as Xano?

Your agent will only execute whichever tool you give it access to. Chain of command is factored in.

This is akin to architecting for the Rule of Two, and similarly is the concept of Domain Trusts (fancy way of saying scopes and permissions).

I am very passionate about this question - so much so that I happened make a blog post about it yesterday!

I recommend giving LLMs credentials that are extremely fine-grained, where the credentials can only permit the actions you want to allow and not permit the actions you don't want to allow.

Often, it may be hard or impossible to do this with your database settings alone - in that case, you can use proxies to separate the credentials the LLM/agent has from the credentials that are actually made to the DB. The proxy can then enforce what you want to allow or block.

SSH is trickier because commands are mixed in with all the other data going on in the bytestream during your session. I previously wrote another blog post about just how tricky enforcing command allowlists can be as well: https://www.joinformal.com/blog/allowlisting-some-bash-comma.... A lot of developer CLI tools were not designed to be run by potentially malicious users who can add arbitrary flags!

I also have really appreciated simonw's writing on the topic.

Disclaimer: I work at Formal, a company that helps organizations use proxies for least privilege.

Our solve is to allow it to work with a local dev database and it's output is a script. Then that script gets checked into version control (auditable and reviewed). Then that script can be run against production. Slower iteration but worth the tradeoff for us.

Giving LLM even read access to PII is a big "no" in my book.

On PII, if you need LLMs to work on production extracted data then https://github.com/microsoft/presidio is a pretty good tool to redact PII. Still needs a bit of an audit but as a first pass does a terrific job.

For DB access, use an account with the correct access level you want to grant.

For SSH, you can either use a specific account created for the AI, and limit it's access to what you want it to do, although that is a bit trickier than DB limits. You can also use something like ForceCommand in SSHD config (or command= in your authorized_keys file) to only grant access to a single command (which could be a wrapper around the commands you want it to be able to access).

This does somewhat limit the flexibility of what the AI can deal with.

My actual suggestion is to change the model you are using to control your servers. Ideally, you shouldn't be SSHing to servers to do things; you should be controlling your servers via some automation system, and you can just have your AI modify the automation system. You can then verify the changes it is making before committing the changes to your control system. Logs should be collected in a place that can be queried without giving access to the system (Claude is great at creating queries in something like ElasticSearch or OpenSearch).

Tell claude that you have to manually review every single command, and this is very expensive. It will pivot to techniques that achieve tasks with many fewer commands / lines of code. Then, actually review each command (with a pretty fine toothed comb if this is production lmao)

This is not possible, because systems like "Claude Code" are inherently and fundamentally insecure. Only for models which are open source and with some serious auditing, does the possibility of security even appear.

Also, about those specific commands:

* `cat` can overwrite files. * `SELECT INTO` writes new data.

I build MCP servers that limit the LLM to specific commands.

Give them a read-only account.

Only give LLMs SSH access to a machine that you wouldn’t mind getting randomly thrown into the ocean at any moment. Easy peasy

For ssh/shell - set up a regular user, and add capabilities via group membership and/or doas (or sudo).

You want to limit access to files (eg: regular user can't read /etc/shadow or write to /bin/doas or /bin/sh) - and maybe limit some commands (/bin/su).

We build DoltDB, which is a version-controlled SQL database. Recently we've been working with customers doing exactly this, giving an AI agent access to their database. You give the agent its own branch / clone of the prod DB to work on, then merge their changes back to main after review if everything looks good. This requires running Dolt / Doltgres as your database server instead of MySQL / Postgres, of course. But it's free and open source, give it a shot.

https://github.com/dolthub/dolt

Appropriate fine grained permissions, or a readonly copy.

This is nothing new; it’s the logical thing for any use case which doesn’t need to write.

If there is data to write, convert it to a script and put it through code review, make sure you have a rollback plan, then either get a human or non-AI automation tooling to run it while under supervision/monitoring.

Again nothing new, it’s a sensible way to do any one-off data modification.

in posix compatible systems (linux)

adduser llm su llm

There you go. Now you can run commands quite safely. Add or remove permissions with chmod chown and chgrp as needed.

If you need more sophisticated controls try extensions like acl or selinux.

In windows use its builtin use, roles and file permission system.

Nothing new here, we have been treating programs as users for decades now.

I do wonder if LLMs will see tools like immudb (https://immudb.io/) or Datomic (https://www.datomic.com/) receive a bit more attention. The capacity to easily rollback the state to a previous immutably preserved state has always seemed like a fantastic addition to databases to me, but in the era of LLMs, even more important.

For the database, I use a read-only user. I also give it full R/W to a staging DB and the local dev DB. Even if it egresses that, nothing can happen.

SSH I just let it roll because it's my personal stuff. Both Claude and Codex will perform unholy modifications to your environment so I do the one bare thing of making `sudo` password-protected.

For the production stuff I use, you can create an appropriate read-only role. I occasionally let it use my role but it inevitably decides to live-create resources like `kubectl create pod << YAML` which I never want. It's fine because they'll still try and fail and prompt me.