diff --git a/scripts/opencode-builder.sh b/scripts/opencode-builder.sh
index 46d542a53..9b5c1da3d 100755
--- a/scripts/opencode-builder.sh
+++ b/scripts/opencode-builder.sh
@@ -45,28 +45,32 @@ IDLE_THRESHOLD_MS=180000  # 3 minutes — session considered idle if last_active
 # Script paths
 SCRIPT_DIR="/app/.opencode/skills/auto-agents-system/scripts"
 
-# Resolve a stable tsx binary path. Using `npx --yes tsx` is unsafe under
-# concurrency: when many invocations start simultaneously with a cold (or
-# even partially-warm) npm cache, they race on writes to ~/.npm/_npx/.../
-# and corrupt each other with `ENOTEMPTY: rename '.../esbuild' ...` errors,
-# crashing all but one and leaving the cache in a broken state for some time
-# afterwards. We install tsx once into ~/.local/node_modules and call that
-# binary directly, bypassing npx entirely.
+# Make tsx discoverable on PATH. Running `npx --yes tsx` concurrently with
+# a cold or partially-warm npm cache causes a race in `~/.npm/_npx/<hash>/`:
+# multiple npm processes simultaneously try to rename `node_modules/esbuild`
+# to the same atomic-backup name and fail with
+# `ENOTEMPTY: rename '.../esbuild' -> '.../esbuild-7kCFO8Lm'`, crashing
+# all but one of them and leaving the cache broken for follow-on calls.
+# When tsx is on PATH, npx skips its install/cache logic entirely and just
+# execs the existing binary — so the race disappears without changing any
+# call sites. We install tsx once into ~/.local/node_modules and prepend
+# its bin dir to PATH for the rest of this script's process tree.
 TSX_PREFIX="${HOME}/.local"
-TSX_BIN="${TSX_PREFIX}/node_modules/.bin/tsx"
-if ! [[ -x "$TSX_BIN" ]]; then
+TSX_BIN_DIR="${TSX_PREFIX}/node_modules/.bin"
+if ! [[ -x "${TSX_BIN_DIR}/tsx" ]]; then
   printf "[%s] Installing tsx into %s …\n" "$(date +%H:%M:%S)" "$TSX_PREFIX" >&2
   mkdir -p "$TSX_PREFIX"
   npm install --prefix "$TSX_PREFIX" --silent tsx >/dev/null 2>&1 \
     || { printf "ERROR: failed to install tsx into %s\n" "$TSX_PREFIX" >&2; exit 1; }
 fi
+export PATH="${TSX_BIN_DIR}:${PATH}"
 
-SESSION_LIST="$TSX_BIN ${SCRIPT_DIR}/session_list.ts"
-SESSION_FIND_PREFIX="$TSX_BIN ${SCRIPT_DIR}/session_find_by_prefix.ts"
-SESSION_START="$TSX_BIN ${SCRIPT_DIR}/session_start.ts"
-SESSION_MESSAGES="$TSX_BIN ${SCRIPT_DIR}/session_messages.ts"
-SESSION_DELETE="$TSX_BIN ${SCRIPT_DIR}/session_delete.ts"
-SESSION_STOP="$TSX_BIN ${SCRIPT_DIR}/session_stop.ts"
+SESSION_LIST="npx --yes tsx ${SCRIPT_DIR}/session_list.ts"
+SESSION_FIND_PREFIX="npx --yes tsx ${SCRIPT_DIR}/session_find_by_prefix.ts"
+SESSION_START="npx --yes tsx ${SCRIPT_DIR}/session_start.ts"
+SESSION_MESSAGES="npx --yes tsx ${SCRIPT_DIR}/session_messages.ts"
+SESSION_DELETE="npx --yes tsx ${SCRIPT_DIR}/session_delete.ts"
+SESSION_STOP="npx --yes tsx ${SCRIPT_DIR}/session_stop.ts"
 
 # ── Internal state ───────────────────────────────────────────────────────
 SERVER_PID=""
@@ -425,7 +429,7 @@ fetch_list_script() {
   fi
 
   local result
-  result=$(timeout "$SCRIPT_TIMEOUT_SEC" "$TSX_BIN" "$script_path" \
+  result=$(timeout "$SCRIPT_TIMEOUT_SEC" npx --yes tsx "$script_path" \
     --url "$forgejo_url" \
     --pat "$forgejo_pat" \
     --owner "$forgejo_owner" \
@@ -1076,7 +1080,7 @@ main_loop() {
             fi
             cache_keys+=("$cache_key")
             log "[pool:${prefix}]   launching $(basename "$script_path") (cache key: ${cache_key})..."
-            timeout "$SCRIPT_TIMEOUT_SEC" "$TSX_BIN" "$script_path" \
+            timeout "$SCRIPT_TIMEOUT_SEC" npx --yes tsx "$script_path" \
               --url "$FORGEJO_URL" \
               --pat "$FORGEJO_PAT" \
               --owner "$FORGEJO_OWNER" \