Architecture Diagrams

System architecture diagrams and flow charts. See also: Three-Lane Model.

Three-Lane Overview

```mermaid flowchart TB %% Three-Lane overview with wrapped labels classDef box fill:#eef5ff,stroke:#4c6ef5,color:#222,stroke-width:1px

subgraph Plugin[Plugin Container\n(no outbound network)] P1["LLM Plugin\nclassify=PHI\ntrace_id=...\nrefs not raw PHI"]:::box end

CoreGW["Core Gateway\n(Operator RPC)"]:::box Canonical["Canonical Engine\n(schema + policy + audit)"]:::box Proxy["Core Proxy\n(allowlist + TLS + secrets)"]:::box Vectorizer["Vectorizer Plugin\n(Embed op)"]:::box

P1 -- "Operator: Embed" → CoreGW CoreGW -- "dispatch" → Vectorizer P1 -- "Canonical: DocumentSummarized" → Canonical P1 -- "Proxy: chat completions" → Proxy

class P1,CoreGW,Canonical,Proxy,Vectorizer box ```

Defaults and Fallbacks

```mermaid flowchart TB %% Default backends and fail-safe fallbacks classDef box fill:#f4fff4,stroke:#2e7d32,color:#222,stroke-width:1px classDef warn fill:#fff8e1,stroke:#f9a825,color:#222,stroke-width:1px

subgraph Core[Core Services] DB[(Postgres\npostgresql+asyncpg)]:::box RAG[(Redis\nredis://localhost:6379/0)]:::box end

subgraph Fallbacks[Graceful Fallbacks] MemDB[(SQLite in-tests\nTEST_DB_URL or in-memory)]:::warn MemRAG[(In-memory RAG\nif Redis unreachable)]:::warn end

Core → Fallbacks DB -. tests only .-> MemDB RAG -. on failure .-> MemRAG ```