diff --git a/scripts/probe-member-credentials.sh b/scripts/probe-member-credentials.sh
new file mode 100755
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--- /dev/null
+++ b/scripts/probe-member-credentials.sh
@@ -0,0 +1,135 @@
+#!/usr/bin/env bash
+#
+# CB-596 step 1: measure which credentials a live member actually holds.
+#
+# The claim under test is that a member's herdr pane starts a LOGIN shell, that shell sources
+# ${SHARED_ENV}/tools/secrets.sh, and so a member inherits every name that file exports — while
+# CB-592 blocks exactly one of them (GITEA_ACCESS_TOKEN). That is an inference from the code, not a
+# measurement, and issue #82 says plainly: do not build a fix on the inference. This is the
+# measurement.
+#
+# WHY THIS IS A SCRIPT AND NOT A COMMAND SOMEONE TYPES
+#
+# Enumerating credential names inside a member is exactly the action that should need the operator's
+# explicit approval, and the command classifier refuses it. That refusal is correct. This script is
+# the seam: it is one auditable file the operator can read once, top to bottom, and then run — rather
+# than approving an ad-hoc shell pipeline whose behaviour they have to take on trust.
+#
+# WHAT IT WILL NOT DO
+#
+#   * It never prints a credential value, and never any prefix or suffix of one. Not one character.
+#     Issue #82's criterion 1 asked for a 6-character prefix; this prints a truncated SHA-256 instead.
+#     A prefix of a short secret is most of the secret, and it would end up pasted into a ticket. The
+#     hash answers every question the prefix was for — is it set, is it the same value as over there,
+#     is it the CB-592 sentinel — and answers none of the ones it should not.
+#   * It never writes anywhere, never contacts the network, and never touches secrets.sh, which is
+#     the operator's file.
+#
+# HOW TO RUN IT
+#
+#   1. As the operator, in a member's pane (a spawned worker's terminal):
+#        bash scripts/probe-member-credentials.sh
+#   2. For the comparison row, in your OWN shell — a lead, not a member:
+#        bash scripts/probe-member-credentials.sh --allow-outside-member
+#
+# The two outputs side by side are the finding: any name whose hash matches between them is a
+# credential the member holds in full.
+#
+set -uo pipefail
+
+# The names ${SHARED_ENV}/tools/secrets.sh exports, recorded on 2026-08-16 (issue #82). Names only —
+# this list contains no values and never should. If secrets.sh gains a name, this list goes stale and
+# the probe silently stops asking about it; that staleness is itself part of what #82's criterion 4
+# has to solve, so it is called out in the summary rather than hidden.
+NAMES=(
+  AI_GATEWAY_TOKEN BESZEL_ADMIN_EMAIL BESZEL_ADMIN_PASSWORD
+  BESZEL_HUB_URL BESZEL_KEY BESZEL_UNIVERSAL_TOKEN
+  BRAIN_MCP_TOKEN CF_ACCOUNT_ID CF_API_TOKEN
+  CF_USER_TOKEN CONFLUENCE_API_TOKEN CONFLUENCE_USERNAME
+  CONTEXT7_TOKEN GITEA_HOST GITLAB_OAUTH_CLIENT_SECRET
+  GITLAB_PERSONAL_ACCESS_TOKEN GRAFANA_ADMIN_PASSWORD GRAFANA_ADMIN_USER
+  HASS_TOKEN HW_PASSWORD HW_USER
+  LTMS_API_KEY MEMORY_MCP_TOKEN METRICS_PUSH_TOKEN
+  OPENCODE_AUTOMODE_MODEL TELEGRAM_BOT_TOKEN TELEGRAM_CHAT_ID
+  TS_API_KEY TS_AUTHKEY WORKER_GITEA_TOKEN
+  GITEA_ACCESS_TOKEN
+)
+
+allow_outside=0
+for arg in "$@"; do
+  case "$arg" in
+    --allow-outside-member) allow_outside=1 ;;
+    -h|--help) sed -n '2,40p' "$0"; exit 0 ;;
+    *) echo "unknown argument: $arg" >&2; exit 2 ;;
+  esac
+done
+
+if [ "${BRIDGED_MEMBER:-}" != "1" ] && [ "$allow_outside" -eq 0 ]; then
+  cat >&2 <<'EOF'
+refusing to run: BRIDGED_MEMBER is not 1, so this is not a member's shell.
+
+The finding this probe exists for is what a MEMBER holds. Run it in a spawned worker's pane. If you
+meant to take the comparison reading from your own shell, pass --allow-outside-member and the output
+will be labelled as such.
+EOF
+  exit 1
+fi
+
+# Prefer sha256sum (Linux), fall back to shasum (macOS). If neither exists, report presence and
+# length only — degraded, but never a value.
+hasher=""
+if command -v sha256sum >/dev/null 2>&1; then
+  hasher="sha256sum"
+elif command -v shasum >/dev/null 2>&1; then
+  hasher="shasum -a 256"
+fi
+
+digest() { # value -> first 12 hex chars of its sha256, or "-" when no hasher is available
+  [ -z "$hasher" ] && { printf '%s' "-"; return; }
+  printf '%s' "$1" | $hasher | cut -c1-12
+}
+
+if [ "${BRIDGED_MEMBER:-}" = "1" ]; then
+  where="MEMBER (BRIDGED_MEMBER=1)"
+else
+  where="NOT a member — comparison reading only"
+fi
+
+echo "CB-596 credential probe"
+echo "reading from : $where"
+echo "shell        : ${SHELL:-unknown}"
+echo "hash         : ${hasher:-none available — lengths only}"
+# Only printed so the two readings can be told apart when they are pasted side by side.
+echo "host         : $(hostname 2>/dev/null || echo unknown)"
+echo
+printf '%-30s %-7s %6s  %s\n' "NAME" "STATE" "LEN" "SHA256-12"
+printf '%-30s %-7s %6s  %s\n' "------------------------------" "-------" "------" "------------"
+
+set_count=0
+for name in "${NAMES[@]}"; do
+  value="${!name:-}"
+  if [ -z "$value" ]; then
+    printf '%-30s %-7s %6s  %s\n' "$name" "unset" "-" "-"
+  else
+    set_count=$((set_count + 1))
+    printf '%-30s %-7s %6s  %s\n' "$name" "SET" "${#value}" "$(digest "$value")"
+  fi
+done
+
+echo
+echo "$set_count of ${#NAMES[@]} names are set in this shell."
+echo
+cat <<'EOF'
+How to read this:
+
+  * Take the MEMBER reading and the comparison reading, and line them up. A name whose SHA256-12
+    matches on both sides is a credential the member holds in full. That is the finding.
+  * GITEA_ACCESS_TOKEN is the control. CB-592 replaces it with a blocked sentinel, so its hash
+    should DIFFER between the two readings. If it matches, CB-592 is not working and that is the
+    most urgent thing on this page.
+  * AI_GATEWAY_TOKEN matching is expected and correct, not a leak: bridged.yaml names it in
+    `tokenEnv:` for the local and gx profiles, so a member reaching the gateway is by design.
+  * A name that is set here but is NOT in the list above will not appear at all. The list was
+    recorded on 2026-08-16 and does not update itself. Anything added to secrets.sh since then is
+    invisible to this probe — which is the same gap issue #82 criterion 4 asks to close properly.
+EOF