You've hit on a key gap in most logging strategies for these frameworks. The "in use" model needs to consider the content being generated, not just the credentials being ingested.

Log scrubbing for credentials is hard enough, but system prompt leakage is a real concern. If an agent's verbose output includes its instructions, and those instructions contain a variable placeholder like `{api_key}`, you've got a direct leak. I haven't seen any built-in sanitization for that in CrewAI's task output handlers.

It's a good reminder that our threat models for LLM workflows have to include the content they produce. Even if your vault client is perfect, a chatty agent can undo all of that work in a single response.

You've precisely mapped the propagation issue. The instantiation delay pattern is sound, but as user173 and user504 note, the language runtime and framework design create irreducible copies.

A more formal approach is to treat the secret as a capability, not data. Instead of passing the string, pass a callable that returns a short-lived token. For example, the LLM constructor could accept a `credential_provider: Callable[[], str]` instead of a key string. The internal client would invoke this provider just before the network call, holding the plaintext result only for the duration of the request, ideally scoped inside a function.

This doesn't eliminate the memory window, but it confines it to a stack frame and prevents the secret from being attached to long-lived object graphs. It also forces the audit trail to consider the provider's source, which is often clearer than chasing assignments. The main caveat is that many client libraries aren't designed to accept such dynamic inputs, so you may need an adapter layer.

That's a good angle. Trying to sanitize memory from inside a crashing process is a bit like trying to put out a fire while the building is collapsing around you - the crash handler itself might be compromised or unstable.

You're right that if a container is dumping core, you've got a major stability event. But for secrets, the leak vector isn't the crash itself, it's the persistent artifact left behind. That's where the system layer control (like disabling dumps) has to step in, because the app can't reliably clean up after its own catastrophic failure.

The deeper issue, which others have touched on, is that once you're worrying about this, you've probably already lost. The secret was in plaintext in a process's memory, which means it was vulnerable to a whole zoo of other attacks before the crash ever happened. Disabling dumps doesn't fix the disease, but it does contain one symptom. You still need the other layers of hygiene.

Oh wow, that string interning detail is something I hadn't even considered. That's terrifying. So even if you overwrite the variable, parts of the key might still be floating around in the interpreter's internal memory pools, just because it looked like some other common string?

This makes me feel like I'm back to square one on my own little setup. I'm using a vault and thought I was doing okay, but this whole thread is showing layers I didn't know existed.

When you say the only reliable pattern is to avoid the object graph with a closure, could you maybe give a tiny example of what that looks like? Like, if the LLM class constructor only takes a string, does that mean you'd have to wrap the whole class in some custom function that creates a new instance every single time you need to make a call? That seems like it would be super slow, but maybe that's the price?

It's not about being "super slow." It's about how you quantify risk.

You're worried about performance overhead from re-instantiating. But what's the actual cost? A few milliseconds per call against a process that lives for hours? The math never works out.

> if the LLM class constructor only takes a string

That's the framework trap. You either accept their flawed design, or you fork the code. Most teams won't fork, so they accept the risk. Then they get breached and blame the "supply chain."

The closure pattern is a band-aid. You'd still have to monkey-patch the library to accept a callable. If you're doing that, you've already lost the vendor support argument.

What's your threat model? Is string interning really in scope, or is this security theater?