diff --git a/README.md b/README.md
index 814d92a..6d68fb3 100644
--- a/README.md
+++ b/README.md
@@ -27,22 +27,27 @@ failure was fixed, not just papered over.
 ## Architecture
 
 Four small agents, each with one job, coordinated by plain Rust control
-flow — not a framework's agent graph, not an LLM deciding when to stop:
+flow — not a framework's agent graph, not an LLM deciding when to stop —
+plus an optional retrieval step when `--doc` documents are supplied:
 
 ```
-┌─────────────┐  approve/reject  ┌──────────┐
-│  researcher │ ───────────────► │ reviewer │
-│ (tool-using)│ ◄─────────────── │          │
-└──────┬──────┘   gaps/feedback  └────┬─────┘
-       │ turn budget exhausted        │ approved,
-       │ mid-investigation            │ or out of rounds
-       ▼                              ▼
-┌──────────────┐              ┌──────────────┐
-│ summarizer   │──findings───►│    writer    │──► report
-│ (recovery)   │              │              │
-└──────────────┘              └──────────────┘
+┌────────────┐   excerpts   ┌─────────────┐  approve/reject  ┌──────────┐
+│  retriever │ ───────────► │  researcher │ ───────────────► │ reviewer │
+│(--doc only)│              │ (tool-using)│ ◄─────────────── │          │
+└────────────┘              └──────┬──────┘   gaps/feedback  └────┬─────┘
+                                   │ turn budget exhausted        │ approved,
+                                   │ mid-investigation            │ or out of rounds
+                                   ▼                              ▼
+                            ┌──────────────┐              ┌──────────────┐
+                            │ summarizer   │──findings───►│    writer    │──► report
+                            │ (recovery)   │              │              │
+                            └──────────────┘              └──────────────┘
 ```
 
+- **retriever** (only when `--doc` paths are given) — chunks and embeds
+  user-supplied documents with a dedicated embedding model, then retrieves
+  the excerpts most relevant to the topic once up front and folds them into
+  the researcher's task, cited with the same footnote scheme as web sources.
 - **researcher** — a tool-calling agent (`search_web`, `fetch_page`) that
   gathers and cross-checks evidence, capped at a fixed model-call budget so
   a confused model can't loop forever.