OpenAPPA

OpenAPPA sits between an agent and its tools and answers one question before every action: is this data allowed to go to this destination?

It is powered by APPA (Agentic Permissions Policy Algebra). OpenAPPA tracks the sensitivity and trust of everything an agent reads and checks each tool call against it before the call runs, so sensitive data never reaches an unauthorized tool. Classifiers and PII detectors are probabilistic, while this check is deterministic and returns the same decision on every run.

Policy is declarative TOML. The engine decides from the event log alone and makes no network or file calls, so the same log always gets the same decision. Run it in-process, or as a sidecar process that checks each tool call before it runs.