diff --git a/.env.example b/.env.example
index d8f1379..3790e49 100644
--- a/.env.example
+++ b/.env.example
@@ -63,11 +63,6 @@
 # Set to 1 to enable.
 # BRIGADE_LOG_ROUTING=
 
-# Override the host-environment tag in the system prompt's runtime line
-# (e.g. "linux", "macos", "windows", or a custom label). When unset, Brigade
-# auto-detects from `process.platform`.
-# BRIGADE_HOST_ENV=
-
 # ───────────────────────────────────────────────────────────────────────────
 # 3. Agent loop / model behaviour
 # ───────────────────────────────────────────────────────────────────────────
diff --git a/README.md b/README.md
index bff331a..9f5d58e 100644
--- a/README.md
+++ b/README.md
@@ -729,7 +729,6 @@ wipes everything it knows.
 | `BRIGADE_CONVEX_URL` | Convex deployment URL (implies convex mode) |
 | `BRIGADE_ENCRYPTION_KEY` | At-rest encryption master key (hex) |
 | `BRIGADE_ENABLE_INBOX_PERSIST` | Persist the sub-agent inbox to JSONL (auto-on at gateway boot) |
-| `BRIGADE_HOST_ENV` | Override the host-environment tag in the system prompt's runtime line |
 
 ---