Substrate Overview

Kairos Substrate is the Rust-native evaluation engine at the core of the Kairos on-premise stack. It provides deterministic, real-time structural risk assessment that runs entirely within your infrastructure — no cloud calls, no data exfiltration, no external dependencies at evaluation time.

What Substrate Does

Substrate sits between your autonomous system and the actions it wants to take. Every proposed action passes through the Substrate evaluation pipeline, which:

1. Scales domain metrics (capability index, alignment score, etc.) into simulation parameters ($\lambda$, $\gamma$) using calibrated mapping functions
2. Runs the physics engine to compute stability, reachability, and warning signals
3. Applies policy gates — state thresholds, action preview, hazard detection — to produce a PASS or REJECT decision
4. Returns a structured response with the decision, evaluation detail, and optional escalation directives

The entire pipeline is deterministic: same inputs always produce the same outputs, with bit-for-bit reproducible traces.

Distribution Targets

Substrate compiles from a single Rust codebase to three distribution targets:

Target	Build output	Use case
CLI binary	kairos executable	Trace tooling, scenario management, policy/license operations, single-shot evaluation, live TUI dashboard
Native library	cdylib / staticlib + C header	C FFI and Python (PyO3) bindings for embedded integration
WASM module	wasm32-unknown-unknown	Browser/Node.js integration for advisory (non-authoritative) evaluation

The CLI and native library targets are authoritative — they enforce licensing, policy signatures, and cryptographic HITL override verification. The WASM target is intentionally advisory: policy signature and license checks are skipped, and HITL tokens are uniformly rejected. Authoritative enforcement must run on a licensed native build.

Audience

• Integration engineers embedding Substrate into autonomous pipelines (LLM agents, MoE routers, robotics controllers)
• Safety operators monitoring live systems via the kairos observe TUI and HITL override protocol
• Platform teams deploying, configuring, and maintaining Substrate infrastructure on-premise

What’s in This Section

Area	Covers
Architecture	Crate map, data flow, key types
Getting Started	Build from source, licensing, first evaluation
Fly-by-Wire	Stateful evaluation loop, action gating, hazard detection
Configuration	Calibration artifacts, deployment policies, feature flags
CLI Reference	All CLI commands and flags