diff --git a/README.md b/README.md
index 2302a73..6381e27 100644
--- a/README.md
+++ b/README.md
@@ -91,13 +91,26 @@ Monorepo with Git submodules. Each submodule has its own Go module (except `el`
 
 ---
 
+## Architecture
+
+Ollie has two session manager backends that run side-by-side. Both embed the same core library and expose the same features; they differ in interface philosophy and deployment context.
+
+| | 9P (`olliesrv`) | D-Bus (`ollied`) |
+|---|---|---|
+| Interface | Synthetic filesystem | Desktop bus methods + signals |
+| Best for | Scripts, remote access, containers, multi-agent | Desktop apps, KDE integration, GUI frontends |
+| Network | Native (mount over TCP) | Local session bus |
+| Dependencies | None beyond Go runtime | D-Bus daemon, desktop session |
+
+Use whichever fits your environment — or both at once.
+
+---
+
 ## 9P: everything is a file
 
-The 9P filesystem server (`olliesrv`) exposes the entire agent runtime as a synthetic filesystem. This is not a convenience wrapper — it is the primary interface, and it provides architectural benefits that no RPC or REST API can match.
+The 9P server exposes the agent runtime as a synthetic filesystem. Every session is a directory; every operation is a read or write.
 
-### Why a filesystem?
-
-Every session is a directory. Every operation is a read or write. There is no client library, no SDK, no protocol buffer — `echo`, `cat`, `tail`, and `rm` are the API.
+There is no client library, no SDK, no protocol buffer — `echo`, `cat`, `tail`, and `rm` are the API.
 
 ```sh
 # Create a session