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Ghost Knowledge

Facts that exist in the system but can't be traced to an author or source.

Ghost Knowledge is one of the most dangerous problems in agentic systems, because it looks like everything is working. The system "knows" something — a configuration value, a design decision, a constraint — but nobody can tell you where that knowledge came from. Did a human set it? Did an agent infer it? Was it from last week's session or six months ago? When Ghost Knowledge turns out to be wrong, debugging is nearly impossible because there's no trail to follow. The knowledge is there, haunting the system, with no provenance.

Example
An agentic system "knows" that the application should use port 8443 for HTTPS. Three team members check — none of them set that value. It's not in the config files, the documentation, or any commit message. An agent inferred it during a debugging session two months ago and stored it as a fact. The team has been deploying to port 8443 ever since, and it works — until it doesn't, and nobody can explain why that port was chosen or whether it matters. That's Ghost Knowledge: correct by accident, untraceable by design.

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