diff --git a/zsh/zshrc b/zsh/zshrc
index 8d625ca..9c44084 100644
--- a/zsh/zshrc
+++ b/zsh/zshrc
@@ -107,12 +107,35 @@ opc() {
     [[ -n $value ]] || { print -u2 "opc: empty value for $name; nothing changed"; return 1; }
   fi
   # [concealed] makes it a password field; an existing field of that name is updated.
-  _dotfiles_op sh -c 'op item edit "$OP_ITEM" --vault "$OP_VAULT" "$1[concealed]=$2" >/dev/null' \
-    opc "$name" "$value" && ops
+  # op can exit non-zero with "(404) Not Found" after an edit it did save (seen with
+  # op 2.34.1 and 2.39.0), so its exit code is ignored: the field is read back instead.
+  _dotfiles_op sh -c '
+    clean() { printf "%s" "${1:-(no output)}" | sed "s/^\[ERROR\] [0-9/]* [0-9:]* //"; }
+    ref="op://$OP_VAULT/$OP_ITEM/$1"
+    err=$(op item edit "$OP_ITEM" --vault "$OP_VAULT" "$1[concealed]=$2" 2>&1 >/dev/null)
+    if [ "$(op read "$ref" 2>/dev/null)" = "$2" ]; then
+      printf "opc: saved %s\n" "$ref" >&2
+    else
+      printf "opc: could not save %s\n  op said: %s\n  check vault, item and service-account write access with: opl\n" \
+        "$ref" "$(clean "$err")" >&2
+      exit 1
+    fi' opc "$name" "$value" && ops
 }
 opd() {
   _dotfiles_env_name "$1" opd || return
-  _dotfiles_op sh -c 'op item edit "$OP_ITEM" --vault "$OP_VAULT" "$1[delete]" >/dev/null' opd "$1" \
+  # As in opc, op's exit code is unreliable here: check the item's field labels instead.
+  _dotfiles_op sh -c '
+    clean() { printf "%s" "${1:-(no output)}" | sed "s/^\[ERROR\] [0-9/]* [0-9:]* //"; }
+    ref="op://$OP_VAULT/$OP_ITEM/$1"
+    err=$(op item edit "$OP_ITEM" --vault "$OP_VAULT" "$1[delete]" 2>&1 >/dev/null)
+    if ! item=$(op item get "$OP_ITEM" --vault "$OP_VAULT" --format json 2>&1); then
+      printf "opd: could not re-read %s to confirm the delete\n  op said: %s\n" "$ref" "$(clean "$item")" >&2
+      exit 1
+    elif printf "%s" "$item" | jq -r ".fields[].label" | grep -qxF "$1"; then
+      printf "opd: could not delete %s\n  op said: %s\n" "$ref" "$(clean "$err")" >&2
+      exit 1
+    fi
+    printf "opd: deleted %s\n" "$ref" >&2' opd "$1" \
     && unset "$1" && ops
 }
 opl() {