diff --git a/AGENTS.md b/AGENTS.md
index 4f2fa7d..d7d7ea6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -93,8 +93,9 @@ backlog issues (all deps closed) or orphaned in-progress issues and spawns
 - `CLAUDE_TIMEOUT` — Max seconds for a Claude session (default 7200)
 - `MATRIX_TOKEN`, `MATRIX_ROOM_ID`, `MATRIX_HOMESERVER` — Notifications (optional)
 
-**Lifecycle**: dev-poll.sh → dev-agent.sh → tmux `dev-{project}-{issue}` →
-phase file drives CI/review loop → merge → close issue.
+**Lifecycle**: dev-poll.sh → dev-agent.sh → create Matrix thread + export
+`MATRIX_THREAD_ID` (streams Claude output to thread via Stop hook) → tmux
+`dev-{project}-{issue}` → phase file drives CI/review loop → merge → close issue.
 
 ### Review (`review/`)
 
diff --git a/dev/dev-agent.sh b/dev/dev-agent.sh
index abc61c3..aec79b4 100755
--- a/dev/dev-agent.sh
+++ b/dev/dev-agent.sh
@@ -709,6 +709,27 @@ ${SCRATCH_INSTRUCTION}
 ${PHASE_PROTOCOL_INSTRUCTIONS}"
 fi
 
+# =============================================================================
+# CREATE MATRIX THREAD (before tmux so MATRIX_THREAD_ID is available for Stop hook)
+# =============================================================================
+if [ ! -f "${THREAD_FILE}" ] || [ -z "$(cat "$THREAD_FILE" 2>/dev/null)" ]; then
+  ISSUE_URL="${CODEBERG_WEB}/issues/${ISSUE}"
+  _thread_id=$(matrix_send_ctx "dev" \
+    "🔧 Issue #${ISSUE}: ${ISSUE_TITLE} — ${ISSUE_URL}" \
+    "🔧 <a href='${ISSUE_URL}'>Issue #${ISSUE}</a>: ${ISSUE_TITLE}") || true
+  if [ -n "${_thread_id:-}" ]; then
+    printf '%s' "$_thread_id" > "$THREAD_FILE"
+    # Register thread root in map for listener dispatch
+    printf '%s\t%s\t%s\t%s\t%s\n' "$_thread_id" "dev" "$(date +%s)" "${ISSUE}" "${PROJECT_NAME}" >> "${MATRIX_THREAD_MAP:-/tmp/matrix-thread-map}" 2>/dev/null || true
+  fi
+fi
+
+# Export for on-stop-matrix.sh hook (streams Claude output to thread)
+_thread_id=$(cat "$THREAD_FILE" 2>/dev/null || true)
+if [ -n "${_thread_id:-}" ]; then
+  export MATRIX_THREAD_ID="$_thread_id"
+fi
+
 # =============================================================================
 # CREATE TMUX SESSION
 # =============================================================================
@@ -727,18 +748,6 @@ log "initial prompt sent to tmux session"
 
 # Signal to dev-poll.sh that we're running (session is up)
 echo '{"status":"ready"}' > "$PREFLIGHT_RESULT"
-# Create Matrix thread for this issue (or reuse existing one)
-if [ ! -f "${THREAD_FILE}" ] || [ -z "$(cat "$THREAD_FILE" 2>/dev/null)" ]; then
-  ISSUE_URL="${CODEBERG_WEB}/issues/${ISSUE}"
-  _thread_id=$(matrix_send_ctx "dev" \
-    "🔧 Issue #${ISSUE}: ${ISSUE_TITLE} — ${ISSUE_URL}" \
-    "🔧 <a href='${ISSUE_URL}'>Issue #${ISSUE}</a>: ${ISSUE_TITLE}") || true
-  if [ -n "${_thread_id:-}" ]; then
-    printf '%s' "$_thread_id" > "$THREAD_FILE"
-    # Register thread root in map for listener dispatch
-    printf '%s\t%s\t%s\t%s\t%s\n' "$_thread_id" "dev" "$(date +%s)" "${ISSUE}" "${PROJECT_NAME}" >> "${MATRIX_THREAD_MAP:-/tmp/matrix-thread-map}" 2>/dev/null || true
-  fi
-fi
 notify "tmux session ${SESSION_NAME} started for issue #${ISSUE}: ${ISSUE_TITLE}"