diff --git a/docs/automation/cron-jobs.md b/docs/automation/cron-jobs.md
index 1d735a9c99e..84594e46105 100644
--- a/docs/automation/cron-jobs.md
+++ b/docs/automation/cron-jobs.md
@@ -100,6 +100,15 @@ agent primary as a hidden extra retry target.
 
 Use `--announce --channel telegram --to "-1001234567890"` for channel delivery. For Telegram forum topics, use `-1001234567890:topic:123`. Slack/Discord/Mattermost targets should use explicit prefixes (`channel:<id>`, `user:<id>`).
 
+For cron-owned isolated jobs, the runner owns the final delivery path. The
+agent is prompted to return a plain-text summary, and that summary is then sent
+through `announce`, `webhook`, or kept internal for `none`. `--no-deliver`
+does not hand delivery back to the agent; it keeps the run internal.
+
+If the original task explicitly says to message some external recipient, the
+agent should note who/where that message should go in its output instead of
+trying to send it directly.
+
 Failure notifications follow a separate destination path:
 
 - `cron.failureDestination` sets a global default for failure notifications.
@@ -363,6 +372,9 @@ openclaw doctor
 - Delivery mode is `none` means no external message is expected.
 - Delivery target missing/invalid (`channel`/`to`) means outbound was skipped.
 - Channel auth errors (`unauthorized`, `Forbidden`) mean delivery was blocked by credentials.
+- For cron-owned isolated jobs, do not expect the agent to use the message tool
+  as a fallback. The runner owns final delivery; `--no-deliver` keeps it
+  internal instead of allowing a direct send.
 
 ### Timezone gotchas
 
diff --git a/docs/cli/cron.md b/docs/cli/cron.md
index 407505787d3..f31c7ca6714 100644
--- a/docs/cli/cron.md
+++ b/docs/cli/cron.md
@@ -19,6 +19,10 @@ Tip: run `openclaw cron --help` for the full command surface.
 Note: isolated `cron add` jobs default to `--announce` delivery. Use `--no-deliver` to keep
 output internal. `--deliver` remains as a deprecated alias for `--announce`.
 
+Note: cron-owned isolated runs expect a plain-text summary and the runner owns
+the final send path. `--no-deliver` keeps the run internal; it does not hand
+delivery back to the agent's message tool.
+
 Note: one-shot (`--at`) jobs delete after success by default. Use `--keep-after-run` to keep them.
 
 Note: `--session` supports `main`, `isolated`, `current`, and `session:<id>`.
@@ -101,6 +105,14 @@ openclaw cron add \
 
 `--light-context` applies to isolated agent-turn jobs only. For cron runs, lightweight mode keeps bootstrap context empty instead of injecting the full workspace bootstrap set.
 
+Delivery ownership note:
+
+- Cron-owned isolated jobs always route final user-visible delivery through the
+  cron runner (`announce`, `webhook`, or internal-only `none`).
+- If the task mentions messaging some external recipient, the agent should
+  describe the intended destination in its result instead of trying to send it
+  directly.
+
 ## Common admin commands
 
 Manual run:
diff --git a/docs/help/faq.md b/docs/help/faq.md
index 32808c93881..d58cb5e2930 100644
--- a/docs/help/faq.md
+++ b/docs/help/faq.md
@@ -1023,6 +1023,29 @@ for usage/billing and raise limits as needed.
 
   </Accordion>
 
+  <Accordion title="Cron fired, but nothing was sent to the channel. Why?">
+    Check the delivery mode first:
+
+    - `--no-deliver` / `delivery.mode: "none"` means no external message is expected.
+    - Missing or invalid announce target (`channel` / `to`) means the runner skipped outbound delivery.
+    - Channel auth failures (`unauthorized`, `Forbidden`) mean the runner tried to deliver but credentials blocked it.
+
+    For isolated cron jobs, the runner owns final delivery. The agent is expected
+    to return a plain-text summary for the runner to send. `--no-deliver` keeps
+    that result internal; it does not let the agent send directly with the
+    message tool instead.
+
+    Debug:
+
+    ```bash
+    openclaw cron runs --id <jobId> --limit 50
+    openclaw tasks show <runId-or-sessionKey>
+    ```
+
+    Docs: [Cron jobs](/automation/cron-jobs), [Background Tasks](/automation/tasks).
+
+  </Accordion>
+
   <Accordion title="How do I install skills on Linux?">
     Use native `openclaw skills` commands or drop skills into your workspace. The macOS Skills UI isn't available on Linux.
     Browse skills at [https://clawhub.ai](https://clawhub.ai).