diff --git a/cspell.json b/cspell.json
index 53981ad..2d1797b 100644
--- a/cspell.json
+++ b/cspell.json
@@ -9,6 +9,7 @@
     "cosign",
     "dedup",
     "devops",
+    "ERRFD",
     "extglob",
     "hadolint",
     "ltrimstr",
diff --git a/docs/man/man1/validate-action-pins.1 b/docs/man/man1/validate-action-pins.1
index 4b62078..2eb58e8 100644
--- a/docs/man/man1/validate-action-pins.1
+++ b/docs/man/man1/validate-action-pins.1
@@ -1,4 +1,4 @@
-.Dd April 18, 2026
+.Dd April 19, 2026
 .Dt VALIDATE-ACTION-PINS 1
 .Os
 .Sh NAME
@@ -132,7 +132,10 @@ scheme or a local
 .Ic ./
 path are skipped.
 .It Cm updates Oo Fl -format Ar plain Ns | Ns Ar tsv Oc Oo Fl -only Ar all Ns | Ns Ar tag Ns | Ns Ar branch Oc Ar file ...
-Report upgrade inventory for each unique pin.
+Report upgrade inventory for each pin, once per file.
+Duplicates within a single file collapse to one record; a pin that
+appears in several files is reported for every file, so operators can
+see each file that needs editing to take an upgrade.
 For tag pins, every tag strictly newer than the current ref is listed
 \(em across both minor and major bumps, since Dependabot does not open
 major-version pull requests by default.
diff --git a/images/ci-tools/bin/validate-action-pins b/images/ci-tools/bin/validate-action-pins
index 6e5530c..d9aa58a 100755
--- a/images/ci-tools/bin/validate-action-pins
+++ b/images/ci-tools/bin/validate-action-pins
@@ -250,6 +250,26 @@ _effective_ref() {
   fi
 }
 
+# Return the owner/repo portion of an action reference, stripping any
+# sub-path segments. GitHub Actions allow path references of the form
+# `owner/repo/path@ref`, where the real repository is `owner/repo` and
+# `path` is a directory within it. API calls (git/ref/tags,
+# git/ref/heads, tags, compare) must target `owner/repo`, not the full
+# action string — otherwise the request 404s.
+#
+# Arguments:
+#   $1 - action string, e.g. `actions/checkout`,
+#        `Homebrew/actions/setup-homebrew`
+#
+# Output:
+#   The first two path segments joined with `/`; the input unchanged
+#   if it already has only two segments.
+_action_repo() {
+  local first="${1%%/*}" rest
+  rest="${1#*/}"
+  echo "${first}/${rest%%/*}"
+}
+
 # Decide whether a pin should be included given the --only filter.
 #
 # Arguments:
@@ -265,34 +285,20 @@ _include_pin() {
   [[ "${1}" == "all" || "${1}" == "${2}" ]]
 }
 
-# Module-scope dedup sets, one per scope boundary that the
-# subcommands care about. The arrays are reset at their respective
-# boundaries (per-file loop in cmd_check, per-invocation entry in
-# cmd_updates) so sourced tests that call a subcommand twice start
-# from a clean state.
-#
-# Scope conventions:
-#   seen_in_file - cmd_check resets inside the per-file loop; one
-#                  OK/FAIL/WARN line per unique pin per file.
-#   seen_in_run  - cmd_updates resets on entry; one record per
-#                  unique pin across the whole invocation.
-#   (cmd_list uses no dedup — every occurrence is listed.)
+# Module-scope dedup set shared by cmd_check and cmd_updates. Reset
+# inside each subcommand's per-file loop so sourced tests that call a
+# subcommand twice start from a clean state. cmd_list uses no dedup —
+# every occurrence is listed.
 declare -A seen_in_file=()
-declare -A seen_in_run=()
 
-# First-occurrence gates. Return 0 the first time a key is seen in
-# the corresponding scope, 1 thereafter. Callers idiomatically chain
-# as `_once_per_X "${key}" || continue`.
+# First-occurrence gate. Returns 0 the first time a key is seen since
+# the last reset, 1 thereafter. Callers idiomatically chain as
+# `_once_per_file "${key}" || continue`.
 _once_per_file() {
   [[ -n "${seen_in_file[${1}]+x}" ]] && return 1
   seen_in_file["${1}"]=1
   return 0
 }
-_once_per_run() {
-  [[ -n "${seen_in_run[${1}]+x}" ]] && return 1
-  seen_in_run["${1}"]=1
-  return 0
-}
 
 # Parse a single `uses:` line into its component fields.
 #
@@ -362,7 +368,7 @@ parse_uses_line() {
 #   $2 - operation name used in the WARN message
 #
 # Output:
-#   WARN line(s) to stdout for every non-200 code
+#   WARN line(s) to stderr for every non-200 code
 #
 # Returns:
 #   0 - status is benign; caller may proceed
@@ -371,21 +377,21 @@ _preflight_classify_status() {
   case "${1}" in
     200) return 0 ;;
     401 | 403)
-      echo "WARN: GitHub API authentication failed (HTTP ${1}) — skipping ${2}"
-      echo "      check GITHUB_TOKEN; an unset or expired token produces this response"
+      echo "WARN: GitHub API authentication failed (HTTP ${1}) — skipping ${2}" >&2
+      echo "      check GITHUB_TOKEN; an unset or expired token produces this response" >&2
       return 1
       ;;
     429)
-      echo "WARN: GitHub API secondary rate limit hit (HTTP 429) — skipping ${2}"
-      echo "      slow down, set GITHUB_TOKEN, or retry after the Retry-After interval"
+      echo "WARN: GitHub API secondary rate limit hit (HTTP 429) — skipping ${2}" >&2
+      echo "      slow down, set GITHUB_TOKEN, or retry after the Retry-After interval" >&2
       return 1
       ;;
     000)
-      echo "WARN: cannot reach GitHub API — skipping ${2}"
+      echo "WARN: cannot reach GitHub API — skipping ${2}" >&2
       return 1
       ;;
     *)
-      echo "WARN: GitHub API returned unexpected HTTP ${1} — skipping ${2}"
+      echo "WARN: GitHub API returned unexpected HTTP ${1} — skipping ${2}" >&2
       return 1
       ;;
   esac
@@ -408,7 +414,7 @@ _preflight_probe_file() {
   if ! curl "${_CURL_FLAGS[@]}" "${auth_header[@]+"${auth_header[@]}"}" \
     -H "Accept: application/vnd.github+json" \
     "${GITHUB_API_BASE}/rate_limit" > "${body_file}" 2> "${_CURL_ERRFD}"; then
-    echo "WARN: cannot reach GitHub API — skipping ${op}"
+    echo "WARN: cannot reach GitHub API — skipping ${op}" >&2
     return 1
   fi
 }
@@ -465,7 +471,7 @@ check_api_preflight() {
   local cmd
   for cmd in curl jq; do
     if ! command -v "${cmd}" > /dev/null 2>&1; then
-      echo "WARN: ${cmd} not found — skipping ${op}"
+      echo "WARN: ${cmd} not found — skipping ${op}" >&2
       return 1
     fi
   done
@@ -498,12 +504,12 @@ check_api_preflight() {
   remaining="$(jq -r '.resources.core.remaining // empty' < "${body_file}" 2> "${_CURL_ERRFD}" || true)"
   if [[ -n "${remaining}" ]]; then
     if [[ "${remaining}" -le 0 ]]; then
-      echo "WARN: GitHub API rate limit exhausted — skipping ${op}"
-      echo "      set GITHUB_TOKEN to raise the limit from 60 to 5,000 per hour"
+      echo "WARN: GitHub API rate limit exhausted — skipping ${op}" >&2
+      echo "      set GITHUB_TOKEN to raise the limit from 60 to 5,000 per hour" >&2
       return 1
     fi
     if [[ "${remaining}" -lt 20 ]]; then
-      echo "WARN: GitHub API rate limit is low (${remaining} remaining); set GITHUB_TOKEN if ${op} stalls mid-run"
+      echo "WARN: GitHub API rate limit is low (${remaining} remaining); set GITHUB_TOKEN if ${op} stalls mid-run" >&2
     fi
   fi
   return 0
@@ -673,7 +679,7 @@ cmd_check() {
   local -A resolve_cache=()
   local -A compare_cache=()
   local file basename line parsed
-  local action ref kind comment cache_key cached resolved resolved_kind
+  local action ref kind comment repo cache_key cached resolved resolved_kind
   local compare_key behind
 
   # Clean slate in case a sourced test re-enters the subcommand.
@@ -681,7 +687,7 @@ cmd_check() {
 
   for file in "${@}"; do
     if [[ ! -f "${file}" ]]; then
-      echo "WARN: ${file} not found, skipping"
+      echo "WARN: ${file} not found, skipping" >&2
       continue
     fi
     basename="${file##*/}"
@@ -704,8 +710,9 @@ cmd_check() {
       cache_key="${action}#${comment}"
       _once_per_file "${cache_key}" || continue
 
+      repo="$(_action_repo "${action}")"
       if [[ -z "${resolve_cache[${cache_key}]+x}" ]]; then
-        if cached="$(resolve_ref "${action}" "${comment}")"; then
+        if cached="$(resolve_ref "${repo}" "${comment}")"; then
           resolve_cache["${cache_key}"]="${cached}"
         else
           resolve_cache["${cache_key}"]="NONE"
@@ -736,7 +743,7 @@ cmd_check() {
       if [[ "${resolved_kind}" == "branch" ]]; then
         compare_key="${action}#${ref}#${resolved}"
         if [[ -z "${compare_cache[${compare_key}]+x}" ]]; then
-          behind="$(compare_behind "${action}" "${ref}" "${resolved}" || true)"
+          behind="$(compare_behind "${repo}" "${ref}" "${resolved}" || true)"
           compare_cache["${compare_key}"]="${behind}"
         fi
         behind="${compare_cache[${compare_key}]}"
@@ -769,7 +776,7 @@ cmd_check() {
   return 0
 }
 
-# Report upgrade inventory for each unique pin. Always informational
+# Report upgrade inventory for each pin. Always informational
 # — exit 0 on success regardless of whether upgrades are available.
 #
 # The goal is to save time on periodic audits, not to pick "the" next
@@ -778,12 +785,17 @@ cmd_check() {
 # bumps by default). For branch pins, the current branch HEAD is
 # reported so stale SHA-to-branch pins are visible at a glance.
 #
+# Dedup is per-file (matching cmd_check), so a pin that appears in
+# multiple workflow files is reported once per file — operators can
+# see every file that needs editing to take an upgrade. API results
+# are cached per invocation, so repeat pins don't multiply API cost.
+#
 # Arguments:
 #   $1   - format: "plain" or "tsv"
 #   $2   - --only filter: "all", "tag", or "branch"
 #   $3.. - workflow file paths
 #
-# Plain output (one line per unique pin):
+# Plain output (one line per unique pin per file):
 #   <basename>: <action>  current=<ref>  [up-to-date]  (<kind>)
 #   <basename>: <action>  current=<ref>  newer=<t1> <t2> ...  (tag)
 #   <basename>: <action>  current=<ref>  head=<short-sha>  (branch)
@@ -795,7 +807,7 @@ cmd_check() {
 #     tag pins, or the short HEAD SHA for branch pins (empty when
 #     up-to-date in either case).
 #
-# Per-unique-pin API cost:
+# Per-invocation API cost (deduped across files by repo+ref):
 #   - Tag ref:    1 call to /repos/.../tags
 #   - Branch ref: 1 call to /repos/.../git/ref/heads/<branch>
 #   - SHA pin with no # comment: no calls, recorded as "unknown"
@@ -806,11 +818,13 @@ cmd_updates() {
   check_api_preflight "update check" || return 0
 
   local file basename line parsed
-  local action ref kind comment effective_ref effective_kind
-  local newer_tags head_full available key
+  local action ref kind comment effective_ref effective_kind repo
+  local newer_tags head_full available cache_key
 
-  # Per-invocation dedup: report each unique pin once across all files.
-  seen_in_run=()
+  # Per-invocation result caches: keep API calls to one per unique
+  # (repo, ref) pair even when the same pin appears in many files.
+  local -A updates_newer_cache=()
+  local -A updates_head_cache=()
 
   for file in "${@}"; do
     if [[ ! -f "${file}" ]]; then
@@ -818,6 +832,7 @@ cmd_updates() {
       continue
     fi
     basename="${file##*/}"
+    seen_in_file=() # per-file dedup scope
 
     while IFS= read -r line; do
       if ! parsed="$(parse_uses_line "${line}")"; then
@@ -826,9 +841,10 @@ cmd_updates() {
       IFS=$'\t' read -r action ref kind comment <<< "${parsed}"
 
       effective_ref="$(_effective_ref "${kind}" "${ref}" "${comment}")"
-      key="${action}@${effective_ref}"
-      _once_per_run "${key}" || continue
+      _once_per_file "${action}@${effective_ref}" || continue
 
+      repo="$(_action_repo "${action}")"
+      cache_key="${repo}@${effective_ref}"
       newer_tags=""
       head_full=""
       available=""
@@ -839,13 +855,19 @@ cmd_updates() {
         effective_kind="unknown"
       elif [[ "${effective_ref}" =~ ${_SEMVER_RE} ]]; then
         effective_kind="tag"
-        newer_tags="$(list_newer_tags "${action}" "${effective_ref}" || true)"
+        if [[ -z "${updates_newer_cache[${cache_key}]+x}" ]]; then
+          updates_newer_cache["${cache_key}"]="$(list_newer_tags "${repo}" "${effective_ref}" || true)"
+        fi
+        newer_tags="${updates_newer_cache[${cache_key}]}"
         if [[ -n "${newer_tags}" ]]; then
           available="$(tr '\n' ' ' <<< "${newer_tags}" | sed 's/ *$//')"
         fi
       else
         effective_kind="branch"
-        head_full="$(head_sha "${action}" "${effective_ref}" || true)"
+        if [[ -z "${updates_head_cache[${cache_key}]+x}" ]]; then
+          updates_head_cache["${cache_key}"]="$(head_sha "${repo}" "${effective_ref}" || true)"
+        fi
+        head_full="${updates_head_cache[${cache_key}]}"
         if [[ "${kind}" == "sha" && "${ref}" != "${head_full}" && -n "${head_full}" ]]; then
           available="${head_full:0:12}"
         fi
@@ -856,7 +878,7 @@ cmd_updates() {
 
       # For TSV, column 3 is "current_ref" — the classified ref hint
       # except for unknown pins, where we fall back to the original
-      # @ref so the row still points at something recognisable.
+      # @ref so the row still points at something recognizable.
       local col_ref="${effective_ref}"
       [[ "${effective_kind}" == "unknown" ]] && col_ref="${ref}"
 
@@ -907,7 +929,7 @@ cmd_list() {
 
   local -A resolve_cache=()
   local file line parsed action ref kind comment
-  local effective_ref cache_key cached resolved_kind
+  local effective_ref repo cache_key cached resolved_kind
 
   for file in "${@}"; do
     if [[ ! -f "${file}" ]]; then
@@ -927,7 +949,8 @@ cmd_list() {
         else
           cache_key="${action}#${effective_ref}"
           if [[ -z "${resolve_cache[${cache_key}]+x}" ]]; then
-            if cached="$(resolve_ref "${action}" "${effective_ref}")"; then
+            repo="$(_action_repo "${action}")"
+            if cached="$(resolve_ref "${repo}" "${effective_ref}")"; then
               resolve_cache["${cache_key}"]="${cached}"
             else
               resolve_cache["${cache_key}"]="NONE"
diff --git a/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-branch-behind.yml b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-branch-behind.yml
new file mode 100644
index 0000000..d94ed60
--- /dev/null
+++ b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-branch-behind.yml
@@ -0,0 +1,7 @@
+name: subpath-branch-behind
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: foo/br-behind/some-subdir@cccccccccccccccccccccccccccccccccccccccc # main
diff --git a/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-branch.yml b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-branch.yml
new file mode 100644
index 0000000..06af085
--- /dev/null
+++ b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-branch.yml
@@ -0,0 +1,7 @@
+name: subpath-branch
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: foo/br-ok/some-subdir@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa # main
diff --git a/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-tag.yml b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-tag.yml
new file mode 100644
index 0000000..127605a
--- /dev/null
+++ b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/subpath-tag.yml
@@ -0,0 +1,7 @@
+name: subpath-tag
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: foo/bar/some-subdir@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa # v1
diff --git a/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/updates-dup-a.yml b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/updates-dup-a.yml
new file mode 100644
index 0000000..9100d9a
--- /dev/null
+++ b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/updates-dup-a.yml
@@ -0,0 +1,7 @@
+name: updates-dup-a
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: foo/br-ok@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa # main
diff --git a/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/updates-dup-b.yml b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/updates-dup-b.yml
new file mode 100644
index 0000000..cf3181f
--- /dev/null
+++ b/tests/bats/images/ci-tools/validate-action-pins/fixtures/workflows/updates-dup-b.yml
@@ -0,0 +1,7 @@
+name: updates-dup-b
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: foo/br-ok@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa # main
diff --git a/tests/bats/images/ci-tools/validate-action-pins/helpers.bats b/tests/bats/images/ci-tools/validate-action-pins/helpers.bats
index 04d6bd1..3ab3c7e 100644
--- a/tests/bats/images/ci-tools/validate-action-pins/helpers.bats
+++ b/tests/bats/images/ci-tools/validate-action-pins/helpers.bats
@@ -211,3 +211,29 @@ v7.0.0"
   assert_failure 1
   assert_output --partial "unexpected HTTP 503"
 }
+
+# ── _action_repo ────────────────────────────────────────────────────
+
+@test "_action_repo leaves a two-segment action unchanged" {
+  # shellcheck disable=SC1090
+  source "${SCRIPT}"
+  run _action_repo "foo/bar"
+  assert_success
+  assert_output "foo/bar"
+}
+
+@test "_action_repo trims a single sub-path segment" {
+  # shellcheck disable=SC1090
+  source "${SCRIPT}"
+  run _action_repo "foo/bar/some-subdir"
+  assert_success
+  assert_output "foo/bar"
+}
+
+@test "_action_repo trims nested sub-path segments" {
+  # shellcheck disable=SC1090
+  source "${SCRIPT}"
+  run _action_repo "Homebrew/actions/setup-homebrew/extra"
+  assert_success
+  assert_output "Homebrew/actions"
+}
diff --git a/tests/bats/images/ci-tools/validate-action-pins/subcommand-check.bats b/tests/bats/images/ci-tools/validate-action-pins/subcommand-check.bats
index f154045..ac66ae5 100644
--- a/tests/bats/images/ci-tools/validate-action-pins/subcommand-check.bats
+++ b/tests/bats/images/ci-tools/validate-action-pins/subcommand-check.bats
@@ -151,3 +151,19 @@ setup() {
   assert_output --partial "FAIL tag-mismatch.yml:"
   assert_output --partial "does NOT match v1"
 }
+
+# ── sub-path actions (owner/repo/path@ref) ──────────────────────────
+
+@test "sub-path tag pin resolves against the containing repo and prints OK" {
+  run "${SCRIPT}" "${FIXTURES_DIR}/workflows/subpath-tag.yml"
+  assert_success
+  assert_output --partial "OK   subpath-tag.yml: foo/bar/some-subdir@aaaaaaaaaaaa..."
+  assert_output --partial "matches v1"
+}
+
+@test "sub-path branch pin resolves against the containing repo and prints OK" {
+  run "${SCRIPT}" "${FIXTURES_DIR}/workflows/subpath-branch.yml"
+  assert_success
+  assert_output --partial "OK   subpath-branch.yml: foo/br-ok/some-subdir@aaaaaaaaaaaa..."
+  assert_output --partial "matches main"
+}
diff --git a/tests/bats/images/ci-tools/validate-action-pins/subcommand-list.bats b/tests/bats/images/ci-tools/validate-action-pins/subcommand-list.bats
index 3255f80..b1dbd5d 100644
--- a/tests/bats/images/ci-tools/validate-action-pins/subcommand-list.bats
+++ b/tests/bats/images/ci-tools/validate-action-pins/subcommand-list.bats
@@ -135,3 +135,17 @@ setup() {
   assert_success
   assert_output --partial "WARN: cannot reach GitHub API"
 }
+
+# ── sub-path actions (owner/repo/path@ref) ──────────────────────────
+
+@test "list --only=tag classifies a sub-path tag pin via the containing repo" {
+  run "${SCRIPT}" list --only=tag "${FIXTURES_DIR}/workflows/subpath-tag.yml"
+  assert_success
+  assert_output --partial "subpath-tag.yml: foo/bar/some-subdir@"
+}
+
+@test "list --only=branch classifies a sub-path branch pin via the containing repo" {
+  run "${SCRIPT}" list --only=branch "${FIXTURES_DIR}/workflows/subpath-branch.yml"
+  assert_success
+  assert_output --partial "subpath-branch.yml: foo/br-ok/some-subdir@"
+}
diff --git a/tests/bats/images/ci-tools/validate-action-pins/subcommand-updates.bats b/tests/bats/images/ci-tools/validate-action-pins/subcommand-updates.bats
index 19f786a..4a87cab 100644
--- a/tests/bats/images/ci-tools/validate-action-pins/subcommand-updates.bats
+++ b/tests/bats/images/ci-tools/validate-action-pins/subcommand-updates.bats
@@ -114,3 +114,36 @@ setup() {
   assert_output --partial "(tag)"
   refute_output --partial "(branch)"
 }
+
+# ── sub-path actions (owner/repo/path@ref) ──────────────────────────
+
+@test "updates reports short HEAD for a stale sub-path branch pin" {
+  run "${SCRIPT}" updates "${FIXTURES_DIR}/workflows/subpath-branch-behind.yml"
+  assert_success
+  assert_output --partial "foo/br-behind/some-subdir"
+  assert_output --partial "current=main"
+  assert_output --partial "head=bbbbbbbbbbbb"
+  assert_output --partial "(branch)"
+  refute_output --partial "[up-to-date]"
+}
+
+@test "updates lists newer tags for a sub-path tag pin" {
+  run "${SCRIPT}" updates "${FIXTURES_DIR}/workflows/subpath-tag.yml"
+  assert_success
+  assert_output --partial "foo/bar/some-subdir"
+  assert_output --partial "current=v1"
+  assert_output --partial "newer=v6.0.0 v6.0.1 v6.0.2 v7.0.0"
+  assert_output --partial "(tag)"
+  refute_output --partial "[up-to-date]"
+}
+
+# ── per-file dedup across multiple workflow files ───────────────────
+
+@test "updates emits one record per file when the same pin appears in multiple files" {
+  run "${SCRIPT}" updates \
+    "${FIXTURES_DIR}/workflows/updates-dup-a.yml" \
+    "${FIXTURES_DIR}/workflows/updates-dup-b.yml"
+  assert_success
+  assert_output --partial "updates-dup-a.yml: foo/br-ok"
+  assert_output --partial "updates-dup-b.yml: foo/br-ok"
+}