diff --git a/README.md b/README.md
index 9208f26f..2f920a10 100644
--- a/README.md
+++ b/README.md
@@ -9,3 +9,15 @@ Cloud cron runtime for the SN Monetization sub-project (sister to `ClaudeEarnSel
 ## Public repo = unlimited GitHub Actions minutes.
 
 PAT: `ClaudeEarnSelf-gh-pat` (Keychain, `relayhop` user) — repo scope.
+
+## Adding new radar signals
+
+When a new `OPEN_BOUNTY` or other signal is detected, append the tab-separated line to
+data files under `data/sn_targets_accumulated/`.  Use the helper script:
+
+```bash
+# single line
+echo "1503135	Stacker_Sports	3	841	2100	12	16.0	232181	3719	recent@Stacker_Sports|top@Stacker_Sports	OPEN_BOUNTY,SELF_POST_OPP	Weekly Random Sports Pick 'em" | bash scripts/append_signal.sh
+```
+
+The script ensures the header row exists and appends to `all_signals.tsv`.
diff --git a/scripts/append_signal.sh b/scripts/append_signal.sh
new file mode 100644
index 00000000..1de72cf0
--- /dev/null
+++ b/scripts/append_signal.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+# append_signal.sh – Append a single SN radar signal line to all_signals.tsv
+# Usage: echo "<tab-separated-line>" | ./append_signal.sh
+# Or: ./append_signal.sh "<tab-separated-line>"
+
+DATA_FILE="data/sn_targets_accumulated/all_signals.tsv"
+HEADER="# id\tsub\tcol3\tcol4\tcol5\tcol6\tcol7\tcol8\tcol9\tcol10\tcol11\tcol12"
+
+mkdir -p "$(dirname "$DATA_FILE")"
+
+if [ ! -f "$DATA_FILE" ]; then
+    echo "$HEADER" > "$DATA_FILE"
+    echo "Created $DATA_FILE with header."
+fi
+
+if [ $# -ge 1 ]; then
+    LINE="$1"
+else
+    read -r LINE
+fi
+
+echo "$LINE" >> "$DATA_FILE"
+echo "Appended signal to $DATA_FILE"