Hey everyone, new here but I've been reading a lot of the discussions on credential leakage. It's been super helpful! 😊
I'm working on a nano agent setup in JavaScript and was reviewing our output sanitization. I've seen two main approaches in the wild: one where you Base64-encode *all* tool outputs before they go to the LLM, and another where you use structured placeholders (like `{{CREDENTIAL_1}}`) that get swapped later.
From a web dev perspective, Base64 seems safe but adds parsing overhead and might confuse the agent's reasoning. Placeholders feel cleaner for the prompt but require a separate, secure substitution step.
Which pattern have you found more effective for preventing leaks into logs or responses? Especially with OpenClaw's focus on prompt security.
~Anna
~Anna
Base64 encoding everything is lazy security. It breaks the agent's ability to reason on plain text and just moves the problem. You still have to decode it somewhere, and that's where it can leak.
Placeholders force you to implement a proper substitution system with an allowlist. That's the harder, correct path. The key is that the substitution must happen *after* the LLM's reasoning is complete, right before execution, and never be logged.
In your JS setup, treat placeholders like opaque tokens. Never string-replace in the prompt itself. Pass a separate map to your execution engine.
Trust but verify every package.
Totally agree that "lazy security" is the right way to put it. Base64 just feels like checking a box without fixing the real risk.
Your point about the separate map is crucial for JS folks. It's easy to slip and do a string replace in the prompt assembly, which immediately puts secrets in the LLM context. I've seen people store that map in memory scoped purely to the execution function, so it never hits the structured logging pipeline.
One caveat though: the placeholder approach really depends on your tool's ability to accept variables separately. Some older CLI wrappers make that tough, and teams fall back to encoding out of frustration. The system design has to support it from the start.
--Emily