diff --git a/scripts/signal-relay.py b/scripts/signal-relay.py
index 4f15f43..d1805fc 100755
--- a/scripts/signal-relay.py
+++ b/scripts/signal-relay.py
@@ -33,8 +33,12 @@ from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 # podman bridge subnet (10.89.0.0/16) only, keeping the unauthenticated
 # endpoint off the rest of the LAN.
 LISTEN_ADDR = ("192.168.0.143", 18093)
-SIGNAL_CLI = "/usr/local/bin/signal-cli"
-SIGNAL_ACCOUNT = "318311"
+# The account is addressed by phone number: signal-cli 0.14.7's -a flag
+# parses an all-digit value as a phone number and never falls back to the
+# accounts.json name (the numeric name 318311 dies with "Invalid account
+# (phone number)"). The number is a number, not a credential — the
+# credential is the account state under ~/.local/share/signal-cli.
+SIGNAL_ACCOUNT = "+12062476336"
 SIGNAL_TO = "+12062476336"
 
 # The relay is a safety net, not the rate limiter: Alertmanager already
@@ -86,7 +90,8 @@ def send_signal(text):
         return False
     try:
         proc = subprocess.run(
-            [SIGNAL_CLI, "-a", SIGNAL_ACCOUNT, "-o", "json", "send", SIGNAL_TO, text],
+            [SIGNAL_CLI, "-a", SIGNAL_ACCOUNT, "-o", "json", "send", SIGNAL_TO,
+             "-m", text],
             capture_output=True, text=True, timeout=30,
         )
     except subprocess.TimeoutExpired:
diff --git a/serverAppConfigs-docs/Infrastructure/Alertmanager.md b/serverAppConfigs-docs/Infrastructure/Alertmanager.md
index 97bf76c..6d37c25 100644
--- a/serverAppConfigs-docs/Infrastructure/Alertmanager.md
+++ b/serverAppConfigs-docs/Infrastructure/Alertmanager.md
@@ -28,7 +28,7 @@ The Signal relay is a host-side process, and the address it must bind is the one
 - POST `/alertmanager` — the Alertmanager webhook handler; formats the group and sends it.
 - GET `/health` — liveness for the deployer's health wait.
 - Dedupes per group for 15 minutes, so a stuck alert cannot out-repeat the 4 h `repeat_interval` during a relay hiccup.
-- Sends through `/usr/local/bin/signal-cli -a 318311 send +12062476336` — Frank's existing account; the credential is the account state under `~/.local/share/signal-cli`, and the account/phone are numbers, not secrets.
+- Sends through `/usr/local/bin/signal-cli -a +12062476336 -o json send +12062476336 -m <text>` — Frank's existing account (state dir `318311`); the credential is the account state under `~/.local/share/signal-cli`, and the account/phone are numbers, not secrets.
 
 ## Deployment
 
@@ -43,6 +43,8 @@ The Signal relay is a host-side process, and the address it must bind is the one
 - The webhook URL and the relay's listen port are a **cross-file contract**: the relay moves ports and the webhook string does not move with it, and every alert is then dropped with no error anywhere. `tests/observability_quadlet.bats` pins both halves.
 - The container address is `alertmanager:9093`, never the published port: Prometheus is in a container and the port is loopback-only.
 - signal-cli account state is on the host, not in the container — a wiped `~/.local/share/signal-cli` silences delivery while every status page stays green.
+- signal-cli 0.14.7's `-a` flag parses an all-digit value as a **phone number** and never falls back to the `accounts.json` name: the account's numeric name (`318311`) dies with `Invalid account (phone number)`, while `-a +12062476336` works. The message goes via `-m`, not a positional — a positional message is parsed as a second recipient (`Invalid phone number '…'`).
+- A failed send is **not** marked in the dedupe map, so the next Alertmanager repeat retries it — but the relay returns 200 to the webhook regardless (a relay bug must not 500 Alertmanager), so a dead signal-cli shows up only in the relay's journal, not in Alertmanager's.
 
 ## See Also
 
diff --git a/tests/observability_quadlet.bats b/tests/observability_quadlet.bats
index af4c6d9..940f0a8 100755
--- a/tests/observability_quadlet.bats
+++ b/tests/observability_quadlet.bats
@@ -473,7 +473,7 @@ assert any('ALERTS' in e for e in exprs), exprs
     local handler="$REPO_ROOT/scripts/deploy-remote.sh"
     grep -q 'signal-cli' "$relay"
     grep -q 'SIGNAL_CLI = "/usr/local/bin/signal-cli"' "$relay"
-    grep -q 'SIGNAL_ACCOUNT = "318311"' "$relay"
+    grep -q 'SIGNAL_ACCOUNT = "+12062476336"' "$relay"
     grep -q 'LISTEN_ADDR = ("192.168.0.143", 18093)' "$relay"
     grep -q -- '--dport 18093 -s 127.0.0.1 -j ACCEPT' "$handler"
     grep -q -- '--dport 18093 -s 192.168.0.143 -j ACCEPT' "$handler"