nucleus

Moving theorem proving upstream into compilers, sandboxes, and the browser seems like the future when we're dealing with increasingly sophisticated AIs. I'm working on similar formal methods but applied to agent sandboxing; do you see Z3 as a better fit than lean? https://github.com/coproduct-opensource/nucleus

I'm building Nucleus for exactly this problem - using information flow control and formal methods, we can prevent confused deputies by proofs instead of heuristics. Very much WIP, would appreciate any feedback. https://github.com/coproduct-opensource/nucleus

I’ve been building Nucleus because most “agent security” is still policy-only: a config file that says “don’t do bad things,” while the agent can still do them. Nucleus is an OSS experiment that pairs a small, compositional permission model with runtime enforcement: *side effects are only reachable through an enforcing tool proxy*, inside a Firecracker microVM. The envelope is *non-escalating*: it can only tighten or terminate, never silently relax. What works today: * MCP tool proxy with *read / write / run* (enforced inside the microVM) * default-deny egress + DNS allowlist + iptables drift detection (fail-closed) on Linux * time + budget caps enforced * hash-chained audit log + HMAC approval tokens (scoped, expiring) for gated ops What’s missing (being upfront): * web/search tools exist in the model but aren’t wired to MCP yet * remote