diff --git a/VERSION b/VERSION
index be14282..7d85683 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.5.3
+0.5.4
diff --git a/larry.sh b/larry.sh
index 7185e68..c7a9226 100755
--- a/larry.sh
+++ b/larry.sh
@@ -36,7 +36,7 @@ set -o pipefail
 # ─────────────────────────────────────────────────────────────────────────────
 # Config
 # ─────────────────────────────────────────────────────────────────────────────
-LARRY_VERSION="0.5.3"
+LARRY_VERSION="0.5.4"
 LARRY_HOME="${LARRY_HOME:-$HOME/.larry}"
 LARRY_BASE_URL="${LARRY_BASE_URL:-https://raw.githubusercontent.com/bojj27/cloverleaf-larry/main}"
 LARRY_UPDATE_URL="${LARRY_UPDATE_URL:-${LARRY_BASE_URL}/larry.sh}"
@@ -453,22 +453,26 @@ log_append()  { printf '%s\n' "$1" >> "$LOG_FILE"; }
 # ─────────────────────────────────────────────────────────────────────────────
 # Message store helpers
 # ─────────────────────────────────────────────────────────────────────────────
+# NOTE on jq file IO: pass files to jq via stdin redirection, not as argv.
+# On MobaXterm/Cygwin the bundled jq is a Windows-native binary that can't
+# resolve Cygwin paths like /home/mobaxterm/... when they come in as argv.
+# Stdin redirection always works because bash does the path open() itself.
 add_user_text() {
   local content="$1"
   local tmp; tmp=$(mktemp)
-  jq --arg c "$content" '. + [{"role":"user","content":[{"type":"text","text":$c}]}]' "$MESSAGES_FILE" > "$tmp" \
+  jq --arg c "$content" '. + [{"role":"user","content":[{"type":"text","text":$c}]}]' < "$MESSAGES_FILE" > "$tmp" \
     && mv "$tmp" "$MESSAGES_FILE"
 }
 add_assistant_blocks() {
   local blocks="$1"
   local tmp; tmp=$(mktemp)
-  jq --argjson b "$blocks" '. + [{"role":"assistant","content":$b}]' "$MESSAGES_FILE" > "$tmp" \
+  jq --argjson b "$blocks" '. + [{"role":"assistant","content":$b}]' < "$MESSAGES_FILE" > "$tmp" \
     && mv "$tmp" "$MESSAGES_FILE"
 }
 add_user_tool_results() {
   local blocks="$1"
   local tmp; tmp=$(mktemp)
-  jq --argjson b "$blocks" '. + [{"role":"user","content":$b}]' "$MESSAGES_FILE" > "$tmp" \
+  jq --argjson b "$blocks" '. + [{"role":"user","content":$b}]' < "$MESSAGES_FILE" > "$tmp" \
     && mv "$tmp" "$MESSAGES_FILE"
 }
 
diff --git a/lib/oauth.sh b/lib/oauth.sh
index 53683fa..c1092f7 100755
--- a/lib/oauth.sh
+++ b/lib/oauth.sh
@@ -48,6 +48,17 @@ command -v openssl >/dev/null 2>&1 || die "openssl required (for PKCE sha256)"
 
 b64url() { base64 | tr '/+' '_-' | tr -d '=' | tr -d '\n'; }
 
+# jqf — run jq against a file, but pipe the file via stdin so bash handles
+# the path translation. Needed because on MobaXterm/Cygwin the bundled jq
+# may be a Windows-native binary that doesn't understand Cygwin paths like
+# /home/mobaxterm/... when they come in as argv. Stdin redirection always
+# works because bash does the open() itself.
+# Usage: jqf <file> <jq-args...>
+jqf() {
+  local file="$1"; shift
+  jq "$@" < "$file"
+}
+
 urlenc() {
   # Minimal RFC3986-ish URL encoder for the bits we need (spaces, /, :)
   local s="$1"
@@ -164,7 +175,7 @@ EOF
 
 cmd_refresh() {
   [ -f "$OAUTH_FILE" ] || die "no oauth file at $OAUTH_FILE — run 'larry-auth.sh login' first"
-  local refresh_token; refresh_token=$(jq -r '.refresh_token // empty' "$OAUTH_FILE")
+  local refresh_token; refresh_token=$(jqf "$OAUTH_FILE" -r '.refresh_token // empty')
   [ -n "$refresh_token" ] || die "no refresh_token in $OAUTH_FILE — please run login again"
 
   local resp
@@ -182,27 +193,30 @@ cmd_refresh() {
   fi
 
   local now; now=$(date +%s)
+  # Pre-read the old refresh_token so we don't need --slurpfile (which would
+  # take a file path argv-style and break on MobaXterm's Windows-native jq).
+  local prev_refresh; prev_refresh=$(jqf "$OAUTH_FILE" -r '.refresh_token // empty')
   printf '%s' "$resp" \
-    | jq --arg now "$now" --slurpfile prev "$OAUTH_FILE" \
-        '. + {fetched_at: ($now|tonumber), refresh_token: (.refresh_token // $prev[0].refresh_token)}' \
+    | jq --arg now "$now" --arg prev "$prev_refresh" \
+        '. + {fetched_at: ($now|tonumber), refresh_token: (.refresh_token // $prev)}' \
     > "$OAUTH_FILE.new"
   mv "$OAUTH_FILE.new" "$OAUTH_FILE"
   chmod 600 "$OAUTH_FILE"
-  jq -r '.access_token' "$OAUTH_FILE"
+  jqf "$OAUTH_FILE" -r '.access_token'
 }
 
 cmd_ensure() {
   [ -f "$OAUTH_FILE" ] || return 1
   local fetched_at expires_in
-  fetched_at=$(jq -r '.fetched_at // 0' "$OAUTH_FILE")
-  expires_in=$(jq -r '.expires_in // 3600' "$OAUTH_FILE")
+  fetched_at=$(jqf "$OAUTH_FILE" -r '.fetched_at // 0')
+  expires_in=$(jqf "$OAUTH_FILE" -r '.expires_in // 3600')
   local now; now=$(date +%s)
   local expires_at=$((fetched_at + expires_in))
   if [ "$now" -ge $((expires_at - 300)) ]; then
     cmd_refresh >/dev/null 2>&1 || return 1
-    jq -r '.access_token' "$OAUTH_FILE"
+    jqf "$OAUTH_FILE" -r '.access_token'
   else
-    jq -r '.access_token' "$OAUTH_FILE"
+    jqf "$OAUTH_FILE" -r '.access_token'
   fi
 }
 
@@ -212,9 +226,9 @@ cmd_status() {
     return 1
   fi
   local fetched_at expires_in scope
-  fetched_at=$(jq -r '.fetched_at // 0' "$OAUTH_FILE")
-  expires_in=$(jq -r '.expires_in // 3600' "$OAUTH_FILE")
-  scope=$(jq -r '.scope // "(unknown)"' "$OAUTH_FILE")
+  fetched_at=$(jqf "$OAUTH_FILE" -r '.fetched_at // 0')
+  expires_in=$(jqf "$OAUTH_FILE" -r '.expires_in // 3600')
+  scope=$(jqf "$OAUTH_FILE" -r '.scope // "(unknown)"')
   local now; now=$(date +%s)
   local expires_at=$((fetched_at + expires_in))
   local left=$((expires_at - now))