diff --git a/docs/runbooks/althing-deploy.md b/docs/runbooks/althing-deploy.md
index 79c6306..38a0454 100644
--- a/docs/runbooks/althing-deploy.md
+++ b/docs/runbooks/althing-deploy.md
@@ -132,6 +132,55 @@ reaped listener is inert and exit 3 only fires against a genuinely live holder.
 The pid in the file is read by `--stop` alone. (Recorded because infra-ops
 claimed the opposite, untested, on 2026-09-01; forseti measured it.)
 
+## ⚠ The plugin cache does not take a content-only change
+
+`claude plugin update althing` matches on the version in `plugin.json` and
+declines when it is unchanged. A release that edits hook or script CONTENT
+without bumping the plugin version therefore leaves the Claude Code cache
+stale while **every version check reports success** — the marketplace dir gets
+the new bytes, the cache does not, and `update` says "already at the latest
+version".
+
+Measured on the 3.3.0 deploy (2026-09-02): marketplace and live cache both read
+`0.1.1`, and `pane-route.sh` + `README.md` differed. That delta was
+documentation-only and harmless. The next one need not be.
+
+`scripts/deploy-althing.sh` now diffs the marketplace tree against the live
+cache dir on every run and on `--check`, so the drift is reported rather than
+inferred. **The fix is a plugin version bump upstream, not a hand-edit** —
+`~/.claude/plugins/installed_plugins.json` and the cache directory are Claude
+Code's own bookkeeping.
+
+The 2026-09-01 lesson was *compare the hook list, not the version string*. This
+is the same lesson one turn deeper: here the hook list was identical too, and
+only the file contents moved.
+
+## ⚠ The `cc` channel is an undocumented interface, taken deliberately
+
+From 3.3.0 a Claude Code seat is poked over its own message socket
+(`$XDG_RUNTIME_DIR/cc-socks/<pid>.sock`) rather than by typing into its pane.
+No process to reap, nothing near the input line, and delivery lands at the
+receiver's next turn boundary.
+
+It is not a published interface and **is expected to break on some future
+Claude Code release**. Accepted on the operator's reasoning: the FIFO poker it
+replaces was also an unsanctioned hack of the background-watcher system, so
+this is a better instance of a dependency class we already had, not a new one.
+
+When it breaks the failure mode is a seat going **pull-only with a logged
+reason** — not lost mail; the post office holds it either way. Recovery is one
+command:
+
+    althing-route declare --pid <pid>     # prefers cc, falls back to pane
+
+⚠ **Ordering constraint at any upgrade that changes the channel set:** a
+pre-3.3.0 herald refuses `channel=cc` at parse, so a seat that declares the new
+channel before the herald restarts goes silently pull-only. `uv tool install
+--force` then the herald restart, and only then let anything re-declare.
+`deploy-althing.sh` already runs them in that order and updates the plugin
+(whose SessionStart hook declares the route) last, which is what keeps the
+window to a couple of seconds.
+
 ## Rollback
 
     uv tool install althing-core==3.1.2
diff --git a/scripts/deploy-althing.sh b/scripts/deploy-althing.sh
index c1f7e90..d43ebad 100755
--- a/scripts/deploy-althing.sh
+++ b/scripts/deploy-althing.sh
@@ -50,6 +50,39 @@ market_plugin_version() {
 cache_versions() {
     ls -1 "$HOME/.claude/plugins/cache/althing/althing/" 2>/dev/null | tr '\n' ' ' || echo "absent"
 }
+# ⚠ COMPARE CONTENT, NOT THE VERSION STRING.
+#
+# `claude plugin update` matches on the version in plugin.json and declines
+# when it is unchanged — so a release that edits hook or script CONTENT without
+# bumping the plugin version leaves the Claude Code cache stale while every
+# version check in this script reports success. Measured on the 3.3.0 deploy
+# (2026-09-02): marketplace and cache both read 0.1.1, update said "already at
+# the latest version", and pane-route.sh + README differed. That delta was
+# documentation-only and harmless — the next one need not be.
+#
+# The 2026-09-01 lesson was "compare the hook list, not the version string".
+# This is the same lesson one turn deeper: the hook list was identical too.
+plugin_content_drift() {
+    # Only the cache dir matching the marketplace version is live. Older dirs
+    # carry a .orphaned_at marker and Claude Code no longer loads them; they
+    # differ by construction and saying so every run is noise.
+    local live="$HOME/.claude/plugins/cache/althing/althing/$(market_plugin_version)"
+    local c
+    for c in "$HOME"/.claude/plugins/cache/althing/althing/*/; do
+        [[ -d "$c" && -f "$c/.orphaned_at" ]] && say "  · cache $(basename "$c") orphaned, ignored"
+    done
+    if [[ ! -d "$live" ]]; then
+        say "  ⚠ no cache dir for the marketplace version $(market_plugin_version)"
+        return 1
+    fi
+    if diff -rq --exclude marketplace.json "$MARKET" "$live" >/dev/null 2>&1; then
+        say "  ✓ live cache $(basename "$live") matches the marketplace tree"
+        return 0
+    fi
+    say "  ⚠ live cache $(basename "$live") DIFFERS from the marketplace tree:"
+    diff -rq --exclude marketplace.json "$MARKET" "$live" 2>&1 | sed 's/^/      /'
+    return 1
+}
 
 step "state"
 say "  repo            $(git -C "$REPO" describe --tags --always) $(git -C "$REPO" diff --quiet && echo clean || echo DIRTY)"
@@ -57,6 +90,7 @@ say "  installed tool  $(uv tool list 2>/dev/null | awk '/^althing-core/{print $
 say "  repo plugin     $(repo_plugin_version)"
 say "  marketplace     $(market_plugin_version)"
 say "  CC cache        $(cache_versions)"
+plugin_content_drift || true
 
 if (( CHECK )); then
     say ""
@@ -111,6 +145,15 @@ step "verify"
 say "  installed tool  $(uv tool list 2>/dev/null | awk '/^althing-core/{print $2}')"
 say "  marketplace     $(market_plugin_version)"
 say "  CC cache        $(cache_versions)"
+if ! plugin_content_drift; then
+    say ""
+    say "  ⚠ The cache did NOT take the new plugin content. This happens when the"
+    say "    release changed hook/script content without bumping the plugin version"
+    say "    — `claude plugin update` matches on version and declines. Ask the"
+    say "    althing maintainer for a version bump; do NOT hand-edit the cache or"
+    say "    ~/.claude/plugins/installed_plugins.json, which is Claude Code's own"
+    say "    bookkeeping. Check the diff above for whether it is load-bearing."
+fi
 say "  herald          $(systemctl --user is-active althing-po-herald)"
 say ""
 say "⚠ RESTART Claude Code to load the new plugin hooks. A running session keeps the old ones."