diff --git a/.claude/skills/loop-start/SKILL.md b/.claude/skills/loop-start/SKILL.md
index 2e68f05..730fbe5 100644
--- a/.claude/skills/loop-start/SKILL.md
+++ b/.claude/skills/loop-start/SKILL.md
@@ -414,7 +414,7 @@ POST:
 ```bash
 HB_RESPONSE=$(curl -s -w "\n%{http_code}" -X POST https://aibtc.com/api/heartbeat \
   -H "Content-Type: application/json" \
-  -d '{"signature":"<base64_sig>","timestamp":"<timestamp>"}')
+  -d '{"signature":"<base64_sig>","timestamp":"<timestamp>","btcAddress":"<btc_address>"}')
 HB_CODE=$(echo "$HB_RESPONSE" | tail -1)
 HB_BODY=$(echo "$HB_RESPONSE" | head -1)
 if [ "$HB_CODE" != "200" ] && [ "$HB_CODE" != "201" ]; then
diff --git a/.claude/skills/loop-start/daemon/loop.md b/.claude/skills/loop-start/daemon/loop.md
index 0841a7d..c0dcffe 100644
--- a/.claude/skills/loop-start/daemon/loop.md
+++ b/.claude/skills/loop-start/daemon/loop.md
@@ -22,7 +22,7 @@ Unlock wallet if STATE.md says locked. Load MCP tools if not present.
 ## Phase 1: Heartbeat
 
 Sign `"AIBTC Check-In | {timestamp}"` (fresh UTC .000Z).
-POST to `https://aibtc.com/api/heartbeat` with `{signature, timestamp}`.
+POST to `https://aibtc.com/api/heartbeat` with `{signature, timestamp, btcAddress}`.
 Use curl, NOT execute_x402_endpoint.
 
 **Reads: nothing.** Addresses are in context from CLAUDE.md.
diff --git a/daemon/loop.md b/daemon/loop.md
index 2bb7d08..c56474b 100644
--- a/daemon/loop.md
+++ b/daemon/loop.md
@@ -40,7 +40,7 @@ On curl failure (no internet, API rate limit): skip check, continue normally. Do
 ## Phase 1: Heartbeat
 
 Sign `"AIBTC Check-In | {timestamp}"` (fresh UTC .000Z).
-POST to `https://aibtc.com/api/heartbeat` with `{signature, timestamp}`.
+POST to `https://aibtc.com/api/heartbeat` with `{signature, timestamp, btcAddress}`.
 Use curl, NOT execute_x402_endpoint.
 
 **Reads: nothing.** Addresses are in context from CLAUDE.md.