- soul_state
- LEO Soul's portable memory: a compact JSON blob (under 48 KB) holding calibration histograms, Bayesian beliefs, the user model, the curiosity ledger, and neural weights. The customer owns it and passes it back each turn - that round-trip is the learning.
- Stateless engine
- An engine that stores nothing between calls: it reads a soul_state in and returns a fresh one out, writing nothing to disk. It is why there is no conversation content for LEO Soul to store or leak.
- Decision trace
- A readable record of how a turn was decided - the uncertainty measured, checks run, and why it chose to answer, ask, confirm, or refuse. It makes each decision inspectable and auditable.
- Spectator Mode
- A live, content-free window on the agent's metacognition: a real-time dashboard feed of typed event cards - decisions, warnings, anomalies, boundaries, recoveries, and info - streamed as turns run, without exposing one word of message content. Like a pilot's instrument panel: you see the warnings and recoveries, never the conversation. Available on every plan (Free included), with the full six-signal set and exportable reliability reports on paid tiers.
- Risk-based triage
- A near-zero-cost first pass that sizes up each turn's stakes so calm turns take a fast path near pass-through latency and deep scrutiny is spent only where it matters.
- Fail-open guard
- A safety wrapper around every module: on any internal error it degrades to a safe pass-through and marks itself degraded in the trace, so one failed check never costs the turn. It is the default and can be switched to fail-closed for regulated traffic. It governs a module failing, not the service being unreachable - that is the SDK's on_unavailable policy, which defaults to fail-closed.
- Persona
- A named configuration of LEO Soul's caution and behaviour for a given use case, so the same engine can be tuned per agent or product surface.