diff --git a/nix/agent-modules/agent-service.nix b/nix/agent-modules/agent-service.nix
index 5ff30300..d8f72759 100644
--- a/nix/agent-modules/agent-service.nix
+++ b/nix/agent-modules/agent-service.nix
@@ -228,9 +228,11 @@ in
       the agent authenticates to its own provider, so there is no Claude
       login to wait for.
 
-      On `"acp"`, `model`, `effortLevel` and `autoCompact` have no effect
-      (the model is whatever the agent is configured with), and neither the
-      web UI's cancel button nor `/compact` works yet.
+      On `"acp"`, `model` and `effortLevel` are set on the session before
+      each prompt, but only when the session offers that value (otherwise
+      the agent keeps the model it is configured with). `autoCompact` applies
+      as it does on `"claude"`. The web UI's cancel button and `/compact`
+      both work.
 
       Subagents (`hive-subagent-daemon`) run on the same runtime. On
       `"acp"`, each subagent run spawns its own copy of the ACP agent, which