diff --git a/docs/configuration.md b/docs/configuration.md
index e25184ff2..18a3b3d9b 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -152,9 +152,9 @@ deprecation fallback.
 - `every`: duration string (`ms`, `s`, `m`, `h`); default unit minutes. Omit or set
   `0m` to disable.
 - `model`: optional override model for heartbeat runs (`provider/model`).
-- `target`: delivery channel (`last`, `whatsapp`, `telegram`, `none`). Default: `last`.
+- `target`: optional delivery channel (`last`, `whatsapp`, `telegram`, `none`). Default: `last`.
 - `to`: optional recipient override (E.164 for WhatsApp, chat id for Telegram).
-- `prompt`: override the default heartbeat body (`HEARTBEAT`).
+- `prompt`: optional override for the heartbeat body (default: `HEARTBEAT`).
 
 `agent.bash` configures background bash defaults:
 - `backgroundMs`: time before auto-background (ms, default 20000)
diff --git a/docs/heartbeat.md b/docs/heartbeat.md
index 31090ebde..a166365fa 100644
--- a/docs/heartbeat.md
+++ b/docs/heartbeat.md
@@ -38,7 +38,7 @@ surface anything that needs attention without spamming the user.
   - `whatsapp` / `telegram`: force the channel (optionally set `to`).
   - `none`: do not deliver externally; output stays in the session (WebChat-visible).
 - `to`: optional recipient override (E.164 for WhatsApp, chat id for Telegram).
-- `prompt`: override the default heartbeat body.
+- `prompt`: optional override for the heartbeat body (default: `HEARTBEAT`).
 
 ## Behavior
 - Runs in the main session (`session.mainKey`, or `global` when scope is global).