diff --git a/docs/phase-1-exposure-runbook.md b/docs/phase-1-exposure-runbook.md
index 161d1e0..941ea80 100644
--- a/docs/phase-1-exposure-runbook.md
+++ b/docs/phase-1-exposure-runbook.md
@@ -289,9 +289,35 @@ failing — the loudest symptom is silence, which is the hardest kind to notice.
 - **HTTPS first, mining later:** set the URL and token, and pin the feeder to `--mode local` until the SSH
   target exists. Tools then read/write the shared palace while transcripts keep landing in the local one.
 
+`MEMPALACE_REMOTE_URL` is the **full endpoint including `/mcp`, with no trailing slash** — the feeder POSTs
+to it verbatim (`urllib.request.Request(url, data=payload, …)`, `:718`), and §3.5 shows the server matches
+`/mcp` exactly. Matches the existing examples (`docker-compose.mempalace.yml:7`,
+`MEMPALACE_REMOTE_URL=http://<reachable-host>:8765/mcp`). For this fleet:
+`MEMPALACE_REMOTE_URL=https://mempalace.jordbo.se/mcp`
+
 Either way, run the feeder once by hand and read its exit code before trusting the timer. This is
 precisely the failure "one machine first" is meant to contain.
 
+**The same misconfiguration has two different symptoms depending on who invokes the feeder** — checked in
+the code 2026-08-12, and the quieter one is the trap:
+
+| Caller | Behaviour with `REMOTE_URL` set and `SSH_TARGET` unset |
+| --- | --- |
+| direct run, session-end hook, cron | `exit 1` with `error: MEMPALACE_PI_SSH_TARGET unset` (`:298-300`) |
+| **pi-devbox container start** | **silently skips — no error, no log file** (`entrypoint-user.sh:134`: `: # remote palace but no inbox configured — nothing we can ship to; skip quietly`) |
+
+The entrypoint's skip happens *before* the subshell that writes
+`~/.pi/agent/mempalace-catchup.log`, so there is not even an empty log to notice. Someone asking "why is
+nothing from this container in the palace?" finds no artifact at all. The skip is deliberate — there is
+genuinely nothing to ship to — but it is indistinguishable from a healthy run that had nothing to do.
+
+→ On a pi-devbox container, confirm the feeder is actually alive after a flip rather than assuming:
+
+```sh
+mempalace-pi-session --reason manual-check; echo "exit=$?"   # exit=0 and a filed count, not silence
+cat ~/.pi/agent/mempalace-catchup.log                        # missing file = the entrypoint skipped
+```
+
 ---
 
 ## 4. Still open