t1190: Fix worker_never_started:no_sentinel dispatch failures

.agents/scripts/supervisor/cleanup.sh

@@ -284,6 +284,18 @@ cleanup_worker_processes() {
 	rm -f "$pid_file"
 	# t1222: Clean up hang warning marker to prevent stale markers from killing re-dispatched workers
 	rm -f "$SUPERVISOR_DIR/pids/${task_id}.hang-warned" 2>/dev/null || true
+	# t1190: Clean up timestamped dispatch/wrapper scripts for this task.
+	# These are created with timestamps (e.g., t001-dispatch-20260213142302.sh) to
+	# prevent overwrite race conditions. Remove them when the task is cleaned up.
+	local script
+	for script in "$SUPERVISOR_DIR/pids/${task_id}"-dispatch-*.sh \
+		"$SUPERVISOR_DIR/pids/${task_id}"-wrapper-*.sh \
+		"$SUPERVISOR_DIR/pids/${task_id}"-reprompt-*.sh \
+		"$SUPERVISOR_DIR/pids/${task_id}"-reprompt-wrapper-*.sh \
+		"$SUPERVISOR_DIR/pids/${task_id}"-prompt-repeat-*.sh \
+		"$SUPERVISOR_DIR/pids/${task_id}"-prompt-repeat-wrapper-*.sh; do
+		[[ -f "$script" ]] && rm -f "$script" || true
+	done
 
 	if [[ "$killed" -gt 0 ]]; then
 		log_info "Cleaned up worker process for $task_id (PID: $pid)"

.agents/scripts/supervisor/dispatch.sh

@@ -1049,7 +1049,10 @@ do_prompt_repeat() {
 	worker_xdg_config=$(generate_worker_mcp_config "$task_id" 2>/dev/null) || true
 
 	# Write dispatch script
-	local dispatch_script="${SUPERVISOR_DIR}/pids/${task_id}-prompt-repeat.sh"
+	# t1190: Use timestamped filename to prevent overwrite race condition.
+	local pr_dispatch_ts
+	pr_dispatch_ts=$(date +%Y%m%d%H%M%S)
+	local dispatch_script="${SUPERVISOR_DIR}/pids/${task_id}-prompt-repeat-${pr_dispatch_ts}.sh"
 	{
 		echo '#!/usr/bin/env bash'
 		echo "echo 'WORKER_STARTED task_id=${task_id} strategy=prompt_repeat pid=\$\$ timestamp='\$(date -u +%Y-%m-%dT%H:%M:%SZ)"
@@ -1065,9 +1068,12 @@ do_prompt_repeat() {
 	chmod +x "$dispatch_script"
 
 	# Wrapper script with cleanup handlers (t253)
-	local wrapper_script="${SUPERVISOR_DIR}/pids/${task_id}-prompt-repeat-wrapper.sh"
+	# t1190: Use timestamped filename to prevent overwrite race condition.
+	local wrapper_script="${SUPERVISOR_DIR}/pids/${task_id}-prompt-repeat-wrapper-${pr_dispatch_ts}.sh"
 	{
 		echo '#!/usr/bin/env bash'
+		# t1190: Wrapper-level sentinel written before running dispatch script.
+		echo "echo 'WRAPPER_STARTED task_id=${task_id} strategy=prompt_repeat wrapper_pid=\$\$ dispatch_script=${dispatch_script} timestamp='\$(date -u +%Y-%m-%dT%H:%M:%SZ) >> '${new_log_file}' 2>/dev/null || true"
 		echo '_kill_descendants_recursive() {'
 		echo '  local parent_pid="$1"'
 		echo '  local children'
@@ -1118,10 +1124,11 @@ do_prompt_repeat() {
 	chmod +x "$wrapper_script"
 
 	# Dispatch
+	# t1190: Redirect wrapper stderr to log file (not /dev/null) for diagnosis.
 	if command -v setsid &>/dev/null; then
-		nohup setsid bash "${wrapper_script}" &>/dev/null &
+		nohup setsid bash "${wrapper_script}" >>"${new_log_file}" 2>&1 &
 	else
-		nohup bash "${wrapper_script}" &>/dev/null &
+		nohup bash "${wrapper_script}" >>"${new_log_file}" 2>&1 &
 	fi
 	local worker_pid=$!
 	disown "$worker_pid" 2>/dev/null || true
@@ -2588,7 +2595,15 @@ cmd_dispatch() {
 
 	# Write dispatch script to a temp file to avoid bash -c quoting issues
 	# with multi-line prompts (newlines in printf '%q' break bash -c strings)
-	local dispatch_script="${SUPERVISOR_DIR}/pids/${task_id}-dispatch.sh"
+	# t1190: Use timestamped filenames to prevent overwrite race condition when
+	# multiple dispatches run for the same task within a short window. Previously,
+	# a second dispatch would overwrite the dispatch/wrapper scripts before the
+	# first wrapper process had a chance to read them, causing the first wrapper
+	# to execute the second dispatch's script (which writes to a different log file),
+	# leaving the first log file with only the metadata header (no WORKER_STARTED).
+	local dispatch_ts
+	dispatch_ts=$(date +%Y%m%d%H%M%S)
+	local dispatch_script="${SUPERVISOR_DIR}/pids/${task_id}-dispatch-${dispatch_ts}.sh"
 	{
 		echo '#!/usr/bin/env bash'
 		echo "# Startup sentinel (t183): if this line appears in the log, the script started"
@@ -2611,9 +2626,15 @@ cmd_dispatch() {
 	# errors when the dispatch script failed to start (e.g., opencode not found).
 	# Now errors are appended to the log file for diagnosis.
 	# t253: Add cleanup handlers to prevent orphaned children when wrapper exits
-	local wrapper_script="${SUPERVISOR_DIR}/pids/${task_id}-wrapper.sh"
+	# t1190: Use timestamped filename (matches dispatch_ts) to prevent overwrite race.
+	local wrapper_script="${SUPERVISOR_DIR}/pids/${task_id}-wrapper-${dispatch_ts}.sh"
 	{
 		echo '#!/usr/bin/env bash'
+		# t1190: Wrapper-level sentinel — written before running the dispatch script.
+		# If WRAPPER_STARTED appears in the log but WORKER_STARTED does not, the
+		# wrapper ran but the dispatch script failed to start (exec failure, bad shebang,
+		# permission error). This distinguishes "wrapper never ran" from "dispatch failed".
+		echo "echo 'WRAPPER_STARTED task_id=${task_id} wrapper_pid=\$\$ dispatch_script=${dispatch_script} timestamp='\$(date -u +%Y-%m-%dT%H:%M:%SZ) >> '${log_file}' 2>/dev/null || true"
 		echo '# t253: Recursive cleanup to kill all descendant processes'
 		echo '_kill_descendants_recursive() {'
 		echo '  local parent_pid="$1"'
@@ -2678,23 +2699,10 @@ cmd_dispatch() {
 		log_info "Opening Tabby tab for $task_id..."
 		printf '\e]1337;NewTab=%s\a' "'${wrapper_script}'" 2>/dev/null || true
 		# Also start background process as fallback (Tabby may not support OSC 1337)
-		# t253: Use setsid if available (Linux) for process group isolation
-		# Use nohup + disown to survive parent (cron) exit
-		if command -v setsid &>/dev/null; then
-			nohup setsid bash "${wrapper_script}" &>/dev/null &
-		else
-			nohup bash "${wrapper_script}" &>/dev/null &
-		fi
+		_launch_wrapper_script "${wrapper_script}" "${log_file}"
 	else
 		# Headless: background process
-		# t253: Use setsid if available (Linux) for process group isolation
-		# Use nohup + disown to survive parent (cron) exit — without this,
-		# workers die after ~2 minutes when the cron pulse script exits
-		if command -v setsid &>/dev/null; then
-			nohup setsid bash "${wrapper_script}" &>/dev/null &
-		else
-			nohup bash "${wrapper_script}" &>/dev/null &
-		fi
+		_launch_wrapper_script "${wrapper_script}" "${log_file}"
 	fi
 
 	local worker_pid=$!
@@ -2714,6 +2722,24 @@ cmd_dispatch() {
 	return 0
 }
 
+#######################################
+# Launch a wrapper script in the background, surviving parent (cron) exit.
+# t253: Uses setsid if available (Linux) for process group isolation.
+# t1190: Redirects wrapper stderr to log file for startup error diagnosis.
+# Args: wrapper_script log_file
+#######################################
+_launch_wrapper_script() {
+	local wrapper_script="$1"
+	local log_file="$2"
+
+	if command -v setsid &>/dev/null; then
+		nohup setsid bash "${wrapper_script}" >>"${log_file}" 2>&1 &
+	else
+		nohup bash "${wrapper_script}" >>"${log_file}" 2>&1 &
+	fi
+	return 0
+}
+
 #######################################
 # Check the status of a running worker
 # Reads log file and PID to determine state
@@ -3054,7 +3080,10 @@ Task description: ${tdesc:-$task_id}"
 	worker_xdg_config=$(generate_worker_mcp_config "$task_id" 2>/dev/null) || true
 
 	# Write dispatch script with startup sentinel (t183)
-	local dispatch_script="${SUPERVISOR_DIR}/pids/${task_id}-reprompt.sh"
+	# t1190: Use timestamped filename to prevent overwrite race condition.
+	local reprompt_dispatch_ts
+	reprompt_dispatch_ts=$(date +%Y%m%d%H%M%S)
+	local dispatch_script="${SUPERVISOR_DIR}/pids/${task_id}-reprompt-${reprompt_dispatch_ts}.sh"
 	{
 		echo '#!/usr/bin/env bash'
 		echo "echo 'WORKER_STARTED task_id=${task_id} retry=${tretries} pid=\$\$ timestamp='\$(date -u +%Y-%m-%dT%H:%M:%SZ)"
@@ -3071,9 +3100,12 @@ Task description: ${tdesc:-$task_id}"
 
 	# Wrapper script (t183): captures dispatch errors in log file
 	# t253: Add cleanup handlers to prevent orphaned children when wrapper exits
-	local wrapper_script="${SUPERVISOR_DIR}/pids/${task_id}-reprompt-wrapper.sh"
+	# t1190: Use timestamped filename to prevent overwrite race condition.
+	local wrapper_script="${SUPERVISOR_DIR}/pids/${task_id}-reprompt-wrapper-${reprompt_dispatch_ts}.sh"
 	{
 		echo '#!/usr/bin/env bash'
+		# t1190: Wrapper-level sentinel written before running dispatch script.
+		echo "echo 'WRAPPER_STARTED task_id=${task_id} retry=${tretries} wrapper_pid=\$\$ dispatch_script=${dispatch_script} timestamp='\$(date -u +%Y-%m-%dT%H:%M:%SZ) >> '${new_log_file}' 2>/dev/null || true"
 		echo '# t253: Recursive cleanup to kill all descendant processes'
 		echo '_kill_descendants_recursive() {'
 		echo '  local parent_pid="$1"'
@@ -3118,10 +3150,11 @@ Task description: ${tdesc:-$task_id}"
 
 	# t253: Use setsid if available (Linux) for process group isolation
 	# Use nohup + disown to survive parent (cron) exit
+	# t1190: Redirect wrapper stderr to log file (not /dev/null) for diagnosis.
 	if command -v setsid &>/dev/null; then
-		nohup setsid bash "${wrapper_script}" &>/dev/null &
+		nohup setsid bash "${wrapper_script}" >>"${new_log_file}" 2>&1 &
 	else
-		nohup bash "${wrapper_script}" &>/dev/null &
+		nohup bash "${wrapper_script}" >>"${new_log_file}" 2>&1 &
 	fi
 	local worker_pid=$!
 	disown "$worker_pid" 2>/dev/null || true

.agents/scripts/supervisor/evaluate.sh

@@ -52,6 +52,13 @@ extract_log_metadata() {
 		echo "worker_started=false"
 	fi
 
+	# Wrapper startup sentinel (t1190): distinguishes wrapper-never-ran from dispatch-exec-failed
+	if grep -q 'WRAPPER_STARTED' "$log_file"; then
+		echo "wrapper_started=true"
+	else
+		echo "wrapper_started=false"
+	fi
+
 	# Dispatch error sentinel (t183)
 	if grep -q 'WORKER_DISPATCH_ERROR\|WORKER_FAILED' "$log_file" 2>/dev/null; then
 		local dispatch_error
@@ -1014,13 +1021,22 @@ evaluate_worker() {
 	fi
 
 	# Check if worker never started (only dispatch metadata, no WORKER_STARTED sentinel)
-	if [[ "$log_size" -lt 500 ]] && ! grep -q 'WORKER_STARTED' "$tlog" 2>/dev/null; then
+	# t1190: Distinguish between wrapper-never-ran vs dispatch-script-failed:
+	#   - no WRAPPER_STARTED: wrapper process never ran (nohup spawn failed, OS killed it)
+	#   - WRAPPER_STARTED but no WORKER_STARTED: wrapper ran but dispatch script failed
+	#     (exec failure, bad shebang, permission error, dispatch script overwritten)
+	if [[ "$log_size" -lt 500 ]] && ! grep -q 'WORKER_STARTED' "$tlog"; then
 		# Log has metadata but worker never started — extract any error from log
 		local startup_error=""
-		startup_error=$(grep -i 'WORKER_FAILED\|WORKER_DISPATCH_ERROR\|command not found\|No such file\|Permission denied' "$tlog" 2>/dev/null | head -1 | head -c 200 || echo "")
+		startup_error=$(grep -i 'WORKER_FAILED\|WORKER_DISPATCH_ERROR\|command not found\|No such file\|Permission denied' "$tlog" | head -1 | head -c 200 || echo "")
 		if [[ -n "$startup_error" ]]; then
 			echo "failed:worker_never_started:$(echo "$startup_error" | tr ' ' '_' | tr -cd '[:alnum:]_:-')"
+		elif grep -q 'WRAPPER_STARTED' "$tlog"; then
+			# t1190: Wrapper ran but dispatch script failed to produce WORKER_STARTED.
+			# This means the dispatch script exec failed (e.g., CLI not found, bad args).
+			echo "failed:worker_never_started:dispatch_exec_failed"
 		else
+			# t1190: Neither wrapper nor worker started — nohup spawn likely failed.
 			echo "failed:worker_never_started:no_sentinel"
 		fi
 		return 0