diff --git a/README.md b/README.md
index ca19142..806e664 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,9 @@ See [CLAUDE.md](CLAUDE.md) for the environment details and repo conventions, and
 
 ## Collections
 
-_None yet._
+| Collection | What it does | Runs on |
+| --- | --- | --- |
+| [plex](plex/) | Health checks and library-artwork repair for the Plex server | this workstation, targeting odin |
 
 <!-- Add one line per collection:
 | [name](name/) | What it does | Runs on |
diff --git a/plex/.env.example b/plex/.env.example
new file mode 100644
index 0000000..51258b9
--- /dev/null
+++ b/plex/.env.example
@@ -0,0 +1,33 @@
+# Copy to .env and fill in. Never commit the filled-in .env.
+# The repo .gitignore ignores `.env` and `**/.env` everywhere — verify with:
+#   git check-ignore -v plex/.env
+
+# ── Plex HTTP API (required) ─────────────────────────────────────────────────
+# Base URL of the Plex Media Server. Resolves to odin (192.168.90.103) and routes
+# over the tailnet subnet route. Use https:// — plain http 302-redirects.
+# TLS verifies cleanly from `dev` here, unlike odin's myunraid.net vhost.
+PLEX_URL=https://plex.bergerhouse.net
+
+# X-Plex-Token for an admin account on this server.
+# Plex Web -> any library item -> ... -> Get Info -> View XML, then copy the
+# X-Plex-Token query parameter out of the URL that opens.
+PLEX_TOKEN=replace-me
+
+# Set to 1 to skip TLS verification (not needed for PLEX_URL above; here in case
+# the collection is pointed at odin's myunraid.net vhost instead).
+PLEX_INSECURE=0
+
+# ── odin filesystem access (optional — only for the deeper "under the hood" checks) ──
+# Needed to read Plex's logs, Preferences.xml, and the metadata/media appdata
+# dirs directly. Leave blank until an SSH key for this box is authorized on odin.
+ODIN_SSH_HOST=100.101.253.105
+ODIN_SSH_USER=root
+ODIN_SSH_KEY=
+# Path to the Plex appdata dir on odin, as seen from the Unraid host (not the
+# container). Confirm before use — not yet verified.
+ODIN_PLEX_APPDATA=
+
+# ── Unraid GraphQL API (optional — host-level health only) ───────────────────
+# See ../docs/odin-access.md. Base URL WITHOUT the /graphql suffix.
+UNRAID_HOST=https://192-168-90-103.87c90a69c53e7197560c778a63f483e675130f2a.myunraid.net:8443
+UNRAID_API_KEY=
diff --git a/plex/README.md b/plex/README.md
new file mode 100644
index 0000000..08cafab
--- /dev/null
+++ b/plex/README.md
@@ -0,0 +1,104 @@
+# plex
+
+Operational scripts for the Plex Media Server running as a container on **odin**.
+
+Reached at `https://plex.bergerhouse.net` (DNS resolves to odin's LAN address
+`192.168.90.103`, routed over the tailnet — see [../docs/odin-access.md](../docs/odin-access.md)).
+
+| Script | What it does | Mutates? |
+| --- | --- | --- |
+| [bin/plex-health](bin/plex-health) | Read-only health report: server, updates, libraries, unmatched media, Butler tasks, active streams | no |
+| [bin/poster-audit](bin/poster-audit) | Finds items whose poster is missing or does not resolve | no |
+| [bin/poster-repair](bin/poster-repair) | Re-selects the poster for items the audit flags | **yes** |
+
+## Prerequisites
+
+- **Where it runs:** this workstation (`dev`), targeting odin over Tailscale. Nothing
+  needs to be installed on odin itself — everything goes through the Plex HTTP API.
+- **Interpreters:** bash 4+
+- **External tools:** `curl`, `jq`
+- **Access needed:** an admin `X-Plex-Token`. No SSH to odin is required.
+
+Unlike odin's `myunraid.net` vhost, `plex.bergerhouse.net` presents a TLS chain that
+verifies cleanly from `dev` — `PLEX_INSECURE` stays `0` and no `-k` is needed.
+
+## Configuration
+
+Copy `.env.example` to `.env` and fill it in. `.env` is gitignored repo-wide.
+
+| Variable | Required | Description |
+| --- | --- | --- |
+| `PLEX_URL` | yes | Base URL of the server. Use `https://` — plain HTTP 302-redirects. |
+| `PLEX_TOKEN` | yes | Admin `X-Plex-Token`. |
+| `PLEX_INSECURE` | no | `1` to skip TLS verification. Not needed for `PLEX_URL` above. |
+| `PLEX_TIMEOUT` | no | Per-request timeout in seconds (default 30). |
+| `POSTER_JOBS` | no | Parallel HTTP checks during a poster scan (default 8). |
+
+To get a token: Plex Web → any library item → **⋯ → Get Info → View XML**, then copy the
+`X-Plex-Token` query parameter out of the URL that opens.
+
+The remaining `ODIN_*` and `UNRAID_*` variables in `.env.example` are placeholders for
+future scripts that need filesystem or host-level access. Nothing here uses them yet.
+
+## Usage
+
+```bash
+bin/plex-health                      # health report (exit 0 ok / 1 warn / 2 fail)
+bin/plex-health --posters            # also check every poster (slow: 1 request per item)
+
+bin/poster-audit                     # what is broken in TV Shows
+bin/poster-audit --section Movies    # any library, by title or id
+bin/poster-audit --json              # machine-readable
+
+bin/poster-repair --dry-run          # preview, changes nothing
+bin/poster-repair                    # apply
+bin/poster-repair --limit 5          # apply to the first 5 only
+```
+
+A full TV Shows scan makes ~283 HTTP requests and takes a couple of minutes. The scan
+dominates the runtime, not the repair.
+
+## Behaviour notes
+
+- **Idempotent:** yes. `poster-repair` only touches items whose poster does not currently
+  resolve, so a second run repairs nothing. `plex-health` never writes.
+- **Destructive operations:** none. `poster-repair` selects a poster that is *already in
+  the item's metadata bundle* — no image is downloaded, deleted, or overwritten, and no
+  other metadata field is touched. Items with a working poster are skipped, so a
+  manually-chosen poster is never replaced.
+- **`--allow-remote` is the one exception:** for an item with no locally-cached poster it
+  pulls one from the metadata agent over the internet, which may select a different image
+  than the one originally chosen. Off by default.
+- **Scheduling:** manual for now. `plex-health` is cron-safe and exit-code driven if you
+  want it on a timer.
+
+## Gotchas
+
+**A missing poster has two distinct causes, and the Plex UI shows them identically.**
+Checking metadata alone will tell you the library is fine when it is not:
+
+- `MISSING` — the item has no `thumb` field at all.
+- `BROKEN` — the item *has* a `thumb` field, but fetching that URL returns **404**. This
+  was 94 of the 100 affected shows. Any audit that only looks for absent fields misses
+  almost all of them.
+
+**The failure is a lost database pointer, not a lost file.** For a broken item,
+`/library/metadata/<key>/posters` still lists all the candidates — often 85+ of them —
+with the agent's own poster already downloaded into the bundle as a `metadata://` entry.
+What is gone is the `selected: true` flag: every candidate reads `selected: false`, so
+the `thumb` URL resolves to nothing. A working item has exactly one candidate selected.
+Re-selecting the local candidate is therefore instant and needs no internet access.
+
+**Diagnose with the `selected` count, not the poster list length.** An affected show has
+plenty of poster candidates; the count of *selected* ones is the signal.
+
+**`PUT /library/metadata/<key>/poster?url=<candidate>` needs the candidate's `ratingKey`,**
+which for a local candidate is the `metadata://posters/...` string, not the `/library/...`
+path from the same object's `key` field.
+
+**Season and episode posters were not affected** — only show-level ones, and only in the
+TV Shows library. The movie libraries sampled clean. Worth re-checking rather than
+assuming if this recurs.
+
+**The 2-minute tool timeout will kill a full repair run.** Run it with `nohup ... &` and
+tail the log, or use `--limit`.
diff --git a/plex/bin/plex-health b/plex/bin/plex-health
new file mode 100755
index 0000000..717390f
--- /dev/null
+++ b/plex/bin/plex-health
@@ -0,0 +1,242 @@
+#!/usr/bin/env bash
+# Read-only health report for the Plex Media Server.
+#
+# Exit status: 0 = all checks passed, 1 = at least one WARN, 2 = at least one FAIL.
+# Safe to run from cron; makes no changes.
+set -euo pipefail
+
+readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly COLLECTION_DIR="$(dirname "$SCRIPT_DIR")"
+
+# shellcheck source=../lib/plex-api.sh
+. "$COLLECTION_DIR/lib/plex-api.sh"
+# shellcheck source=../lib/posters.sh
+. "$COLLECTION_DIR/lib/posters.sh"
+
+WARNS=0
+FAILS=0
+CHECK_POSTERS=0
+
+# Global, not local: an EXIT trap fires after the owning function has returned,
+# by which point a local would be out of scope and `set -u` would abort cleanup.
+WORKDIR=""
+cleanup() { [[ -n "$WORKDIR" ]] && rm -rf "$WORKDIR"; return 0; }
+trap cleanup EXIT
+
+usage() {
+  cat <<'EOF'
+Usage: plex-health [--posters] [--help]
+
+  --posters   Also run a full poster-integrity check on every show/movie
+              library. Costs one HTTP request per item, so it is off by
+              default; without it the report notes that it was skipped.
+  --help
+
+Exit status: 0 ok, 1 warnings, 2 failures.
+EOF
+}
+
+ok()   { printf '  [ ok ] %s\n' "$*"; }
+warn() { printf '  [warn] %s\n' "$*"; WARNS=$((WARNS + 1)); }
+fail() { printf '  [FAIL] %s\n' "$*"; FAILS=$((FAILS + 1)); }
+info() { printf '  [info] %s\n' "$*"; }
+section() { printf '\n%s\n' "$*"; }
+
+# ── checks ───────────────────────────────────────────────────────────────────
+
+check_server() {
+  section "Server"
+  local root
+  root="$(plex_get /)" || { fail "cannot read server root"; return; }
+
+  local version platform pv user signin sub
+  version="$(jq -r '.MediaContainer.version // "?"' <<<"$root")"
+  platform="$(jq -r '.MediaContainer.platform // "?"' <<<"$root")"
+  pv="$(jq -r '.MediaContainer.platformVersion // "?"' <<<"$root")"
+  user="$(jq -r '.MediaContainer.myPlexUsername // "?"' <<<"$root")"
+  signin="$(jq -r '.MediaContainer.myPlexSigninState // "?"' <<<"$root")"
+  sub="$(jq -r '.MediaContainer.myPlexSubscription // false' <<<"$root")"
+
+  ok "Plex ${version} on ${platform} ${pv}"
+  [[ "$signin" == "ok" ]] && ok "myPlex sign-in: ${user}" || fail "myPlex sign-in state: ${signin}"
+  [[ "$sub" == "true" ]] && ok "Plex Pass subscription active" || info "no active Plex Pass subscription"
+}
+
+check_updates() {
+  section "Updates"
+  local st
+  st="$(plex_get /updater/status)" || { warn "updater status unavailable"; return; }
+  local size can
+  size="$(jq -r '.MediaContainer.size // 0' <<<"$st")"
+  can="$(jq -r '.MediaContainer.canInstall // false' <<<"$st")"
+  if [[ "$size" == "0" ]]; then
+    ok "no server update pending"
+  else
+    info "update available (canInstall=${can}) — this server updates via its Docker image, not in-app"
+  fi
+}
+
+check_remote_access() {
+  section "Remote access"
+  local acct
+  acct="$(plex_get /myplex/account)" || { warn "cannot read myPlex account"; return; }
+  local mstate merr
+  mstate="$(jq -r '.MyPlex.mappingState // "?"' <<<"$acct")"
+  merr="$(jq -r '.MyPlex.mappingError // ""' <<<"$acct")"
+  if [[ -z "$merr" ]]; then
+    ok "port mapping: ${mstate}"
+  else
+    # odin sits behind a Pangolin/Newt tunnel with no open inbound ports, so an
+    # "unreachable" mapping is the expected steady state, not a fault.
+    info "port mapping ${mstate}/${merr} — expected: odin has no open inbound ports (tunnel ingress)"
+  fi
+}
+
+check_libraries() {
+  section "Libraries"
+  local sections
+  sections="$(plex_get /library/sections)" || { fail "cannot list library sections"; return; }
+
+  local key title type refreshing code count
+  while IFS=$'\t' read -r key title type refreshing; do
+    # Top-level item count: movies for a movie library, shows for a show
+    # library. Music sections are counted by artist.
+    case "$type" in
+      movie)  code=1 ;;
+      show)   code=2 ;;
+      artist) code=8 ;;
+      *)      code=1 ;;
+    esac
+    count="$(plex_get "/library/sections/${key}/all" --get --data-urlencode "type=${code}" \
+             | jq -r '.MediaContainer.totalSize // .MediaContainer.size // "?"' 2>/dev/null || echo '?')"
+    if [[ "$refreshing" == "true" ]]; then
+      info "${title} (id ${key}, ${type}): ${count} items — currently refreshing"
+    else
+      ok "${title} (id ${key}, ${type}): ${count} items"
+    fi
+  done < <(jq -r '.MediaContainer.Directory[]|"\(.key)\t\(.title)\t\(.type)\t\(.refreshing)"' <<<"$sections")
+}
+
+check_unmatched() {
+  section "Unmatched media"
+  local sections
+  sections="$(plex_get /library/sections)"
+  local key title type code items unmatched
+  while IFS=$'\t' read -r key title type; do
+    case "$type" in
+      movie) code=1 ;;
+      show)  code=2 ;;
+      *)     continue ;;
+    esac
+    items="$(plex_get "/library/sections/${key}/all" --get --data-urlencode "type=${code}")" || continue
+    # An unmatched item keeps a local:// guid instead of a real agent guid.
+    unmatched="$(jq -r '[.MediaContainer.Metadata[]?
+                        |select((.guid//"")|test("^(local://|com\\.plexapp\\.agents\\.none)"))]|length' <<<"$items")"
+    if [[ "$unmatched" == "0" ]]; then
+      ok "${title}: all items matched to an agent"
+    else
+      warn "${title}: ${unmatched} unmatched item(s) — they will never get metadata or artwork"
+    fi
+  done < <(jq -r '.MediaContainer.Directory[]|"\(.key)\t\(.title)\t\(.type)"' <<<"$sections")
+}
+
+check_posters() {
+  section "Poster integrity"
+  if (( ! CHECK_POSTERS )); then
+    info "skipped (one request per item) — re-run with --posters, or use bin/poster-audit"
+    return
+  fi
+  local sections
+  sections="$(plex_get /library/sections)"
+  local key title type code bad total
+  WORKDIR="$(mktemp -d)"
+  while IFS=$'\t' read -r key title type; do
+    case "$type" in
+      movie) code=1 ;;
+      show)  code=2 ;;
+      *)     continue ;;
+    esac
+    posters_fetch_items "$key" "$code" "$WORKDIR/items.json"
+    posters_scan "$WORKDIR/items.json" > "$WORKDIR/scan.tsv"
+    total="$(wc -l < "$WORKDIR/scan.tsv" | tr -d ' ')"
+    bad="$(awk -F'\t' '$2!="OK"' "$WORKDIR/scan.tsv" | wc -l | tr -d ' ')"
+    if [[ "$bad" == "0" ]]; then
+      ok "${title}: ${total}/${total} posters resolve"
+    else
+      warn "${title}: ${bad}/${total} posters missing or broken — run bin/poster-repair --section '${title}'"
+    fi
+  done < <(jq -r '.MediaContainer.Directory[]|"\(.key)\t\(.title)\t\(.type)"' <<<"$sections")
+}
+
+check_butler() {
+  section "Scheduled maintenance (Butler)"
+  local b
+  b="$(plex_get /butler)" || { warn "cannot read butler tasks"; return; }
+
+  local backup optimize
+  backup="$(jq -r '.ButlerTasks.ButlerTask[]|select(.name=="BackupDatabase")|.enabled' <<<"$b")"
+  optimize="$(jq -r '.ButlerTasks.ButlerTask[]|select(.name=="OptimizeDatabase")|.enabled' <<<"$b")"
+
+  [[ "$backup" == "true" ]]   && ok "database backup enabled"   || warn "database backup DISABLED — no automatic recovery point"
+  [[ "$optimize" == "true" ]] && ok "database optimize enabled" || warn "database optimize disabled"
+
+  local disabled
+  disabled="$(jq -r '[.ButlerTasks.ButlerTask[]|select(.enabled==false)|.name]|join(", ")' <<<"$b")"
+  [[ -n "$disabled" ]] && info "disabled tasks: ${disabled}"
+}
+
+check_activity() {
+  section "Current activity"
+  local s a
+  s="$(plex_get /status/sessions)" || { warn "cannot read sessions"; return; }
+  local streams transcodes
+  streams="$(jq -r '.MediaContainer.size // 0' <<<"$s")"
+  transcodes="$(jq -r '[.MediaContainer.Metadata[]?|select((.TranscodeSession//empty)!=empty)]|length' <<<"$s")"
+  ok "${streams} active stream(s), ${transcodes} transcoding"
+
+  a="$(plex_get /activities)" || return
+  local acts
+  acts="$(jq -r '.MediaContainer.size // 0' <<<"$a")"
+  if [[ "$acts" == "0" ]]; then
+    ok "no background activities running"
+  else
+    info "${acts} background activity/activities: $(jq -r '[.MediaContainer.Activity[]?|.title]|join(", ")' <<<"$a")"
+  fi
+}
+
+main() {
+  while (( $# )); do
+    case "$1" in
+      --posters) CHECK_POSTERS=1 ;;
+      --help|-h) usage; exit 0 ;;
+      *) plex_die "unknown argument: $1 (try --help)" ;;
+    esac
+    shift
+  done
+
+  plex_require_deps
+  plex_load_env "$COLLECTION_DIR/.env"
+
+  printf 'Plex health check — %s\n' "${PLEX_URL:-unset}"
+  plex_check_auth
+  printf '  [ ok ] reachable and authenticated\n'
+
+  check_server
+  check_updates
+  check_remote_access
+  check_libraries
+  check_unmatched
+  check_posters
+  check_butler
+  check_activity
+
+  section "Result"
+  if (( FAILS > 0 )); then
+    printf '  %d failure(s), %d warning(s)\n' "$FAILS" "$WARNS"; exit 2
+  elif (( WARNS > 0 )); then
+    printf '  %d warning(s)\n' "$WARNS"; exit 1
+  fi
+  printf '  all checks passed\n'
+}
+
+main "$@"
diff --git a/plex/bin/poster-audit b/plex/bin/poster-audit
new file mode 100755
index 0000000..9105bb1
--- /dev/null
+++ b/plex/bin/poster-audit
@@ -0,0 +1,109 @@
+#!/usr/bin/env bash
+# Report items whose poster is missing or does not resolve. Read-only.
+set -euo pipefail
+
+readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly COLLECTION_DIR="$(dirname "$SCRIPT_DIR")"
+
+# shellcheck source=../lib/plex-api.sh
+. "$COLLECTION_DIR/lib/plex-api.sh"
+# shellcheck source=../lib/posters.sh
+. "$COLLECTION_DIR/lib/posters.sh"
+
+SECTION="TV Shows"
+TYPE=2
+FORMAT=text
+LIST_OK=0
+
+# Global, not local to main(): an EXIT trap fires after main() returns, by which
+# point a local would be out of scope and `set -u` would abort the cleanup.
+WORKDIR=""
+cleanup() { [[ -n "$WORKDIR" ]] && rm -rf "$WORKDIR"; return 0; }
+trap cleanup EXIT
+
+usage() {
+  cat <<'EOF'
+Usage: poster-audit [--section <id|title>] [--type <n>] [--json] [--list-ok]
+
+  --section   Library section, by id or exact title. Default: "TV Shows".
+  --type      Plex type code: 1=movie 2=show 3=season 4=episode. Default: 2.
+  --json      Emit JSON instead of a human report.
+  --list-ok   Also list items whose poster is fine.
+  --jobs N    Parallel HTTP checks (env POSTER_JOBS, default 8).
+  --help
+
+Statuses:
+  MISSING   no thumb field on the item at all
+  BROKEN    thumb field present, but the URL returns non-200
+
+Read-only: makes no changes. Use poster-repair to fix what this finds.
+EOF
+}
+
+main() {
+  while (( $# )); do
+    case "$1" in
+      --section) SECTION="${2:?--section needs a value}"; shift ;;
+      --type)    TYPE="${2:?--type needs a value}"; shift ;;
+      --json)    FORMAT=json ;;
+      --list-ok) LIST_OK=1 ;;
+      --jobs)    POSTER_JOBS="${2:?--jobs needs a value}"; export POSTER_JOBS; shift ;;
+      --help|-h) usage; exit 0 ;;
+      *) plex_die "unknown argument: $1 (try --help)" ;;
+    esac
+    shift
+  done
+
+  plex_require_deps
+  plex_load_env "$COLLECTION_DIR/.env"
+  plex_check_auth
+
+  local section_id
+  section_id="$(posters_resolve_section "$SECTION")"
+
+  WORKDIR="$(mktemp -d)"
+
+  posters_fetch_items "$section_id" "$TYPE" "$WORKDIR/items.json"
+  posters_scan "$WORKDIR/items.json" | sort -t$'\t' -k3 > "$WORKDIR/scan.tsv"
+
+  local total missing broken ok
+  total="$(wc -l < "$WORKDIR/scan.tsv" | tr -d ' ')"
+  missing="$(awk -F'\t' '$2=="MISSING"' "$WORKDIR/scan.tsv" | wc -l | tr -d ' ')"
+  broken="$(awk -F'\t' '$2=="BROKEN"' "$WORKDIR/scan.tsv" | wc -l | tr -d ' ')"
+  ok="$(awk -F'\t' '$2=="OK"' "$WORKDIR/scan.tsv" | wc -l | tr -d ' ')"
+
+  if [[ "$FORMAT" == json ]]; then
+    jq -Rn --arg section "$SECTION" --arg id "$section_id" --arg type "$TYPE" \
+      --argjson total "$total" --argjson missing "$missing" \
+      --argjson broken "$broken" --argjson ok "$ok" \
+      --rawfile scan "$WORKDIR/scan.tsv" \
+      '{section:$section, sectionId:$id, type:$type,
+        totals:{total:$total, ok:$ok, missing:$missing, broken:$broken},
+        items:[$scan|split("\n")[]|select(length>0)|split("\t")
+               |{ratingKey:.[0], status:.[1], title:.[2]}]
+              | map(select(.status != "OK"))}'
+    return 0
+  fi
+
+  plex_log "Poster audit — section '${SECTION}' (id ${section_id}, type ${TYPE})"
+  plex_log "  total ${total}   ok ${ok}   broken ${broken}   missing ${missing}"
+
+  if (( broken + missing > 0 )); then
+    plex_log ""
+    plex_log "Needs repair:"
+    awk -F'\t' '$2!="OK" {printf "  %-8s %-8s %s\n", $1, $2, $3}' "$WORKDIR/scan.tsv"
+    plex_log ""
+    plex_log "Run: bin/poster-repair --section '${SECTION}' --dry-run"
+  else
+    plex_log ""
+    plex_log "All posters resolve."
+  fi
+
+  if (( LIST_OK )); then
+    plex_log ""
+    plex_log "OK:"
+    awk -F'\t' '$2=="OK" {printf "  %-8s %s\n", $1, $3}' "$WORKDIR/scan.tsv"
+  fi
+}
+
+main "$@"
diff --git a/plex/bin/poster-repair b/plex/bin/poster-repair
new file mode 100755
index 0000000..def9628
--- /dev/null
+++ b/plex/bin/poster-repair
@@ -0,0 +1,134 @@
+#!/usr/bin/env bash
+# Re-select a poster for items whose poster is missing or does not resolve.
+set -euo pipefail
+
+readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly COLLECTION_DIR="$(dirname "$SCRIPT_DIR")"
+
+# shellcheck source=../lib/plex-api.sh
+. "$COLLECTION_DIR/lib/plex-api.sh"
+# shellcheck source=../lib/posters.sh
+. "$COLLECTION_DIR/lib/posters.sh"
+
+SECTION="TV Shows"
+TYPE=2
+DRY_RUN=0
+LIMIT=0
+export POSTER_ALLOW_REMOTE=0
+
+# Global, not local to main(): an EXIT trap fires after main() returns, by which
+# point a local would be out of scope and `set -u` would abort the cleanup.
+WORKDIR=""
+cleanup() { [[ -n "$WORKDIR" ]] && rm -rf "$WORKDIR"; return 0; }
+trap cleanup EXIT
+
+usage() {
+  cat <<'EOF'
+Usage: poster-repair [--dry-run] [--section <id|title>] [--type <n>]
+                     [--limit N] [--allow-remote]
+
+  --dry-run       Show what would be selected; change nothing.
+  --section       Library section, by id or exact title. Default: "TV Shows".
+  --type          Plex type code: 1=movie 2=show 3=season 4=episode. Default: 2.
+  --limit N       Repair at most N items (0 = no limit).
+  --allow-remote  Also repair items with no locally-cached poster by pulling
+                  one from the metadata agent. Off by default: it re-downloads
+                  from the internet and may pick a different image than the one
+                  that was originally chosen.
+  --jobs N        Parallel HTTP checks during the scan (default 8).
+  --help
+
+What it does: for each broken item it selects the poster already sitting in
+that item's metadata bundle. The image is not re-downloaded and no other
+metadata is touched, so this does not overwrite manually-chosen artwork —
+items that still have a working poster are skipped entirely.
+
+Idempotent: re-running repairs nothing once every poster resolves.
+EOF
+}
+
+main() {
+  while (( $# )); do
+    case "$1" in
+      --dry-run)      DRY_RUN=1 ;;
+      --section)      SECTION="${2:?--section needs a value}"; shift ;;
+      --type)         TYPE="${2:?--type needs a value}"; shift ;;
+      --limit)        LIMIT="${2:?--limit needs a value}"; shift ;;
+      --allow-remote) POSTER_ALLOW_REMOTE=1 ;;
+      --jobs)         POSTER_JOBS="${2:?--jobs needs a value}"; export POSTER_JOBS; shift ;;
+      --help|-h)      usage; exit 0 ;;
+      *) plex_die "unknown argument: $1 (try --help)" ;;
+    esac
+    shift
+  done
+
+  plex_require_deps
+  plex_load_env "$COLLECTION_DIR/.env"
+  plex_check_auth
+
+  local section_id
+  section_id="$(posters_resolve_section "$SECTION")"
+
+  WORKDIR="$(mktemp -d)"
+
+  plex_log "Scanning section '${SECTION}' (id ${section_id}, type ${TYPE})..."
+  posters_fetch_items "$section_id" "$TYPE" "$WORKDIR/items.json"
+  posters_scan "$WORKDIR/items.json" | awk -F'\t' '$2!="OK"' | sort -t$'\t' -k3 > "$WORKDIR/broken.tsv"
+
+  local count
+  count="$(wc -l < "$WORKDIR/broken.tsv" | tr -d ' ')"
+  if (( count == 0 )); then
+    plex_log "Nothing to repair — every poster resolves."
+    return 0
+  fi
+  plex_log "Found ${count} item(s) needing repair."
+  (( DRY_RUN )) && plex_log "[dry-run] no changes will be made."
+  plex_log ""
+
+  local repaired=0 skipped=0 failed=0 processed=0
+  local rk status title candidate
+  while IFS=$'\t' read -r rk status title; do
+    if (( LIMIT > 0 && processed >= LIMIT )); then
+      plex_log "Reached --limit ${LIMIT}; stopping."
+      break
+    fi
+    processed=$((processed + 1))
+
+    candidate="$(posters_candidate "$rk")" || candidate=""
+    if [[ -z "$candidate" ]]; then
+      plex_warn "SKIP   ${title} (${rk}, ${status}) — no locally-cached poster; retry with --allow-remote"
+      skipped=$((skipped + 1))
+      continue
+    fi
+
+    if (( DRY_RUN )); then
+      plex_log "[dry-run] would select for ${title} (${rk}): ${candidate:0:72}"
+      repaired=$((repaired + 1))
+      continue
+    fi
+
+    if ! posters_select "$rk" "$candidate"; then
+      plex_warn "FAIL   ${title} (${rk}) — poster selection rejected"
+      failed=$((failed + 1))
+      continue
+    fi
+
+    if posters_verify "$rk"; then
+      plex_log "OK     ${title} (${rk})"
+      repaired=$((repaired + 1))
+    else
+      plex_warn "FAIL   ${title} (${rk}) — selected, but thumb still does not resolve"
+      failed=$((failed + 1))
+    fi
+  done < "$WORKDIR/broken.tsv"
+
+  plex_log ""
+  if (( DRY_RUN )); then
+    plex_log "Summary (dry-run): ${repaired} would be repaired, ${skipped} skipped."
+  else
+    plex_log "Summary: ${repaired} repaired, ${skipped} skipped, ${failed} failed."
+  fi
+  (( failed == 0 ))
+}
+
+main "$@"
diff --git a/plex/docs/tv-poster-incident.md b/plex/docs/tv-poster-incident.md
new file mode 100644
index 0000000..5fbb43e
--- /dev/null
+++ b/plex/docs/tv-poster-incident.md
@@ -0,0 +1,95 @@
+# TV Shows: 101 missing posters (investigated 2026-08-15)
+
+What the symptom looked like, what it actually was, and what is still unknown.
+
+## Symptom
+
+Grey placeholder posters scattered through the **TV Shows** library in the Plex UI.
+
+## Scope
+
+| Library | Type | Affected |
+| --- | --- | --- |
+| TV Shows (id 2) | shows | **101 of 283** (36%) |
+| TV Shows (id 2) | seasons | 0 of 954 |
+| Movies (id 1) | movies | 0 (sampled 60 of 1059) |
+| Movies 4k (id 3) | movies | 0 (sampled 40 of 79) |
+
+Only show-level posters, only in one library. Seasons and episodes were untouched, which
+is why the library still looked half-normal.
+
+## The two failure modes
+
+They are indistinguishable in the UI, and only one is visible to a metadata-only audit:
+
+| Mode | Count | What it looks like in the API |
+| --- | --- | --- |
+| `MISSING` | 6 | the item has no `thumb` field at all |
+| `BROKEN` | 95 | the item **has** a `thumb` field, but fetching it returns **404** |
+
+The 95 BROKEN shows are the trap. `/library/sections/2/all` reports a perfectly
+well-formed `thumb` URL for each one — e.g. `/library/metadata/13343/thumb/1785398727` —
+and only an actual HTTP request reveals it serves an 85-byte HTML 404 page.
+
+## Root cause: a lost selection pointer, not a lost file
+
+For every affected show, `/library/metadata/<key>/posters` still returned a full
+candidate list — 85 to 158 entries — **including the agent's own poster already
+downloaded into the item's metadata bundle** as a `metadata://posters/...` entry.
+
+What was gone was the selection:
+
+```
+affected shows with zero `selected: true` candidates:  101 / 101
+control sample of working shows, selected count:        1 each (15 / 15)
+affected shows with the poster still in the bundle:    100 / 101
+```
+
+So the images were never deleted. The database simply no longer marked *any* candidate as
+selected for those items, and a show with nothing selected has no poster to serve.
+
+Because the file was still local, the repair was a pure database operation — instant, no
+internet round trip, no re-download:
+
+```bash
+PUT /library/metadata/<key>/poster?url=metadata://posters/tv.plex.agents.series_<hash>
+```
+
+Validated on one show (Severance, `13343`) before touching the rest: `thumb` went from
+`404` to `200 image/jpeg`, 533 KB.
+
+## Hypotheses tested and rejected
+
+- **Unmatched media.** Rejected: all 283 shows had real `plex://show/...` GUIDs; none had
+  a `local://` GUID. The affected shows also had full season and episode counts.
+- **A bad bulk metadata refresh.** A refresh clearly did run — 77 shows share an
+  `updatedAt` inside a 35-second window (~2026-07-30). But it does not correlate with the
+  damage: of the items in that window 54 are fine and 23 are broken, while 72 broken items
+  sit outside it entirely. Rejected as *the* cause.
+- **A stale/expired thumb URL format.** Rejected: broken and working items had
+  structurally identical `thumb` URLs with timestamps from the same refresh.
+
+## Still unknown
+
+**Which event cleared the selection flags.** Establishing that needs the Plex server logs
+on odin (`Plex Media Server.log`), which requires filesystem access to the container's
+appdata — not available from `dev` at the time of writing (no SSH key is authorized on
+odin). The `CleanOldBundles` Butler task is enabled on a 7-day interval and is the obvious
+suspect to check first, but note that it does **not** fit the evidence cleanly: the poster
+files survived in the bundles: only the database pointers were lost.
+
+Worth watching: if posters rot again on roughly a 7-day cadence, that points at a Butler
+task; if it correlates with a Plex version bump, it points at a migration.
+
+## Repair record
+
+| Step | Result |
+| --- | --- |
+| Validation on Severance | poster restored, verified `200 image/jpeg` |
+| Bulk repair, local candidates | 100 shows restored |
+| True Detective (no local candidate) | restored via `--allow-remote` from the agent |
+| Final audit | **283 / 283 posters resolve** |
+
+Tooling built from this: [../bin/poster-audit](../bin/poster-audit) and
+[../bin/poster-repair](../bin/poster-repair). Re-run the audit if the symptom returns —
+it is read-only and will say in a couple of minutes whether it is the same failure.
diff --git a/plex/lib/plex-api.sh b/plex/lib/plex-api.sh
new file mode 100644
index 0000000..3c950ed
--- /dev/null
+++ b/plex/lib/plex-api.sh
@@ -0,0 +1,95 @@
+# shellcheck shell=bash
+# Sourced helper for talking to the Plex Media Server HTTP API.
+# Not executable — source it: . "$COLLECTION_DIR/lib/plex-api.sh"
+#
+# Provides: plex_load_env, plex_require_deps, plex_get, plex_get_raw, plex_put,
+#           plex_check_auth, plex_log, plex_warn, plex_die
+
+plex_log()  { printf '%s\n' "$*"; }
+plex_warn() { printf '%s\n' "$*" >&2; }
+plex_die()  { plex_warn "error: $*"; exit 1; }
+
+# Load the collection's .env into the environment. Silent if absent — the
+# caller's :? checks produce the actionable message.
+plex_load_env() {
+  local env_file="${1:?plex_load_env needs a path}"
+  [[ -f "$env_file" ]] || return 0
+  set -a; . "$env_file"; set +a
+}
+
+plex_require_deps() {
+  local missing=()
+  local dep
+  for dep in curl jq; do
+    command -v "$dep" >/dev/null 2>&1 || missing+=("$dep")
+  done
+  (( ${#missing[@]} == 0 )) || plex_die "missing required tools: ${missing[*]}"
+}
+
+# Assemble the curl flags shared by every request. PLEX_INSECURE=1 adds -k;
+# plex.bergerhouse.net verifies cleanly from `dev`, so it should stay 0.
+_plex_curl_flags() {
+  local -n out=$1
+  out=(--silent --show-error --location-trusted --max-time "${PLEX_TIMEOUT:-30}")
+  [[ "${PLEX_INSECURE:-0}" == "1" ]] && out+=(--insecure)
+  return 0
+}
+
+# plex_get <path> [query...] -> JSON on stdout
+# Path is relative to PLEX_URL and must start with '/'. Extra args are passed to
+# curl, so use --get --data-urlencode 'k=v' for query parameters.
+plex_get() {
+  local path="${1:?plex_get needs a path}"; shift
+  local flags; _plex_curl_flags flags
+  curl "${flags[@]}" \
+    -H 'Accept: application/json' \
+    -H "X-Plex-Token: ${PLEX_TOKEN}" \
+    "$@" \
+    "${PLEX_URL%/}${path}"
+}
+
+# Same as plex_get but returns the server's default XML — a few endpoints
+# (notably /library/sections/<id>/all with includeGuids) are richer in XML.
+plex_get_raw() {
+  local path="${1:?plex_get_raw needs a path}"; shift
+  local flags; _plex_curl_flags flags
+  curl "${flags[@]}" \
+    -H "X-Plex-Token: ${PLEX_TOKEN}" \
+    "$@" \
+    "${PLEX_URL%/}${path}"
+}
+
+# plex_put <path> [curl args...] — mutating request. Callers are responsible for
+# honouring --dry-run before calling this.
+plex_put() {
+  local path="${1:?plex_put needs a path}"; shift
+  local flags; _plex_curl_flags flags
+  curl "${flags[@]}" -X PUT \
+    -H 'Accept: application/json' \
+    -H "X-Plex-Token: ${PLEX_TOKEN}" \
+    "$@" \
+    "${PLEX_URL%/}${path}"
+}
+
+# Fail fast with a useful message rather than letting every later call return
+# an empty body. Plex answers 401 with an HTML body for a bad/absent token.
+plex_check_auth() {
+  : "${PLEX_URL:?PLEX_URL is not set — copy .env.example to .env}"
+  : "${PLEX_TOKEN:?PLEX_TOKEN is not set — copy .env.example to .env}"
+  [[ "$PLEX_TOKEN" != "replace-me" ]] || plex_die "PLEX_TOKEN is still the placeholder value"
+
+  local flags; _plex_curl_flags flags
+  local code
+  code="$(curl "${flags[@]}" -o /dev/null -w '%{http_code}' \
+    -H "X-Plex-Token: ${PLEX_TOKEN}" "${PLEX_URL%/}/identity")" \
+    || plex_die "cannot reach ${PLEX_URL} (Tailscale down?)"
+  [[ "$code" == "200" ]] || plex_die "${PLEX_URL}/identity returned HTTP ${code}"
+
+  code="$(curl "${flags[@]}" -o /dev/null -w '%{http_code}' \
+    -H "X-Plex-Token: ${PLEX_TOKEN}" "${PLEX_URL%/}/library/sections")"
+  case "$code" in
+    200) return 0 ;;
+    401) plex_die "PLEX_TOKEN rejected (HTTP 401) — the token is wrong or expired" ;;
+    *)   plex_die "/library/sections returned HTTP ${code}" ;;
+  esac
+}
diff --git a/plex/lib/posters.sh b/plex/lib/posters.sh
new file mode 100644
index 0000000..ca1c9ab
--- /dev/null
+++ b/plex/lib/posters.sh
@@ -0,0 +1,127 @@
+# shellcheck shell=bash
+# Poster integrity helpers for the Plex library.
+# Sourced by bin/poster-audit and bin/poster-repair. Requires lib/plex-api.sh
+# to be sourced first.
+#
+# The distinction that matters here: a poster can be missing in two ways, and
+# they look identical in the Plex UI.
+#
+#   MISSING  the item has no `thumb` field at all
+#   BROKEN   the item has a `thumb` URL, but fetching it returns 404
+#
+# BROKEN is the common one: the poster image is still present in the item's
+# metadata bundle, but the database no longer marks any candidate as selected,
+# so the thumb URL resolves to nothing.
+
+# Resolve a section by numeric id or by exact title. Echoes the id.
+posters_resolve_section() {
+  local want="${1:?posters_resolve_section needs an id or title}"
+  local sections
+  sections="$(plex_get /library/sections)" || plex_die "could not list library sections"
+
+  if [[ "$want" =~ ^[0-9]+$ ]]; then
+    jq -e --arg k "$want" '.MediaContainer.Directory[]|select(.key==$k)|.key' <<<"$sections" -r \
+      || plex_die "no library section with id ${want}"
+    return
+  fi
+
+  local matches
+  matches="$(jq -r --arg t "$want" '[.MediaContainer.Directory[]|select(.title==$t)|.key]|join(" ")' <<<"$sections")"
+  case "$(wc -w <<<"$matches")" in
+    0) plex_die "no library section titled '${want}' — have: $(jq -r '[.MediaContainer.Directory[].title]|join(", ")' <<<"$sections")" ;;
+    1) printf '%s\n' "$matches" ;;
+    *) plex_die "library title '${want}' is ambiguous (ids: ${matches}) — pass the id instead" ;;
+  esac
+}
+
+# Fetch every item of <type> in <section> into a JSON file.
+# Plex type codes: 1=movie 2=show 3=season 4=episode.
+posters_fetch_items() {
+  local section="${1:?}" type="${2:?}" out="${3:?}"
+  plex_get "/library/sections/${section}/all" --get --data-urlencode "type=${type}" -o "$out" \
+    || plex_die "could not list items for section ${section} type ${type}"
+  jq -e '.MediaContainer|has("Metadata") or .size==0' "$out" >/dev/null \
+    || plex_die "unexpected response listing section ${section} (not a library container?)"
+}
+
+# Emit "ratingKey<TAB>STATUS<TAB>title" for every item, checking each thumb URL
+# with a real HTTP request. Runs POSTER_JOBS requests in parallel.
+#
+# The 404 check is the whole point: Plex happily reports a thumb field for
+# items whose poster does not resolve, so a metadata-only audit reports a
+# clean library while the UI shows grey placeholders.
+posters_scan() {
+  local items_json="${1:?}"
+  local jobs="${POSTER_JOBS:-8}"
+
+  # Items with no thumb field at all need no HTTP request.
+  jq -r '.MediaContainer.Metadata[]?|select(has("thumb")|not)|"\(.ratingKey)\tMISSING\t\(.title)"' "$items_json"
+
+  jq -r '.MediaContainer.Metadata[]?|select(has("thumb"))|"\(.ratingKey)\t\(.thumb)\t\(.title)"' "$items_json" \
+    | PLEX_URL="$PLEX_URL" PLEX_TOKEN="$PLEX_TOKEN" PLEX_INSECURE="${PLEX_INSECURE:-0}" \
+      xargs -P "$jobs" -d '\n' -I{} bash -c '
+        IFS=$'"'"'\t'"'"' read -r rk thumb title <<<"{}"
+        flags=(--silent --show-error --max-time 30)
+        [[ "${PLEX_INSECURE:-0}" == "1" ]] && flags+=(--insecure)
+        code=$(curl "${flags[@]}" -o /dev/null -w "%{http_code}" \
+                 -H "X-Plex-Token: ${PLEX_TOKEN}" "${PLEX_URL%/}${thumb}")
+        if [[ "$code" == "200" ]]; then
+          printf "%s\tOK\t%s\n" "$rk" "$title"
+        else
+          printf "%s\tBROKEN\t%s\n" "$rk" "$title"
+        fi'
+}
+
+# Echo the best poster candidate URL for an item, or nothing if there is none.
+#
+# Prefers a metadata:// candidate — that image is already downloaded into the
+# item's bundle, so selecting it is instant and needs no internet round trip.
+# Falls back to a remote provider URL only when POSTER_ALLOW_REMOTE=1, since
+# that re-downloads from the agent and can fail or pick a different image.
+posters_candidate() {
+  local rk="${1:?posters_candidate needs a ratingKey}"
+  local list
+  list="$(plex_get "/library/metadata/${rk}/posters")" || return 1
+
+  local local_candidate
+  local_candidate="$(jq -r '[.MediaContainer.Metadata[]?|select(.ratingKey|startswith("metadata://"))][0].ratingKey // empty' <<<"$list")"
+  if [[ -n "$local_candidate" ]]; then
+    printf '%s\n' "$local_candidate"
+    return 0
+  fi
+
+  if [[ "${POSTER_ALLOW_REMOTE:-0}" == "1" ]]; then
+    jq -r '[.MediaContainer.Metadata[]?|select(.ratingKey|startswith("http"))][0].ratingKey // empty' <<<"$list"
+    return 0
+  fi
+  return 0
+}
+
+# How many candidates are currently marked selected. 0 is the broken state.
+posters_selected_count() {
+  local rk="${1:?}"
+  plex_get "/library/metadata/${rk}/posters" \
+    | jq -r '[.MediaContainer.Metadata[]?|select(.selected==true)]|length'
+}
+
+# Select <url> as the poster for <ratingKey>. Returns non-zero on HTTP failure.
+posters_select() {
+  local rk="${1:?}" url="${2:?}"
+  local code
+  code="$(plex_put "/library/metadata/${rk}/poster" -o /dev/null -w '%{http_code}' \
+            --get --data-urlencode "url=${url}")"
+  [[ "$code" == "200" ]] || { plex_warn "  PUT poster for ${rk} returned HTTP ${code}"; return 1; }
+}
+
+# Re-read the item and confirm its thumb now actually resolves.
+posters_verify() {
+  local rk="${1:?}"
+  local thumb
+  thumb="$(plex_get "/library/metadata/${rk}" | jq -r '.MediaContainer.Metadata[0].thumb // empty')"
+  [[ -n "$thumb" ]] || return 1
+  local flags; _plex_curl_flags flags
+  local code
+  code="$(curl "${flags[@]}" -o /dev/null -w '%{http_code}' \
+            -H "X-Plex-Token: ${PLEX_TOKEN}" "${PLEX_URL%/}${thumb}")"
+  [[ "$code" == "200" ]]
+}