diff --git a/.env.example b/.env.example
index 131e86a3..34c1a940 100644
--- a/.env.example
+++ b/.env.example
@@ -222,6 +222,18 @@ MCP_DOCMOST_PASSWORD=
 # CLOUD=true) — run a single instance instead. The server logs a startup WARNING
 # when it detects a multi-instance deployment (CLOUD=true) so the constraint is
 # visible, and a startup sweep settles any run left dangling by a restart.
+#
+# Resumable run streams (#184 phase 1.5, #381). With the flag ON, an active
+# durable run tees its SSE frames into an in-memory registry, and a
+# reloaded/second tab attaches via GET /ai-chat/runs/:chatId/stream to follow the
+# run LIVE (replay of the buffered frames + the live tail). With the flag OFF
+# (default) the registry is never populated and attach always answers 204, so a
+# reopened tab of an active run silently falls back to degraded 2.5s history
+# polling — every wire path stays byte-for-byte identical to a build without the
+# feature. Staged-rollout switch: only meaningful when autonomousRuns (above) is
+# enabled for a workspace, and the same single-instance constraint applies (the
+# registry is process-local).
+# AI_CHAT_RESUMABLE_STREAM=false
 
 # --- Anonymous public-share AI assistant ---
 # Opt-in per workspace (AI settings -> "public share assistant"; off by default).