Explanation¶

Understanding-oriented documentation: why Tend is shaped the way it is. Read these when you want the reasoning, not a procedure.

Architecture (C4 views)¶

The architecture is documented as C4 model views, from context down to components:

System context (C4 L1) — Tend, its users, and the systems around it.
Containers (C4 L2) — the deployable pieces: operator, gateways, delivery, evidence, and how they talk.
Operator components (C4 L3) — inside the Tend operator: reconcilers and the state machines.
Data gateway components (C4 L3) — inside the sole data path: identity, scope decisions, connectors, the access log.

Governance model — contract-not-code: why generated code is never reviewed, and what is enforced instead.
The evidence chain — from prompt hash to signed attestation to queryable history.
Boundary tiers — Tier 1 (cloud-private) inference, which is the only tier that has run, and Tier 2 (self-hosted), which is reserved and not exercised.
App lifecycle — owner sync, expiry, composable freeze causes, retirement and restore, durable history vs. transient Events, the cost axis; why enforcement rather than suggestion.
The constitution — the seven binding principles and how compliance is proven in CI.

Significant architecture decisions are recorded as ADRs — each with context, the decision, alternatives rejected, and consequences.