diff --git a/lib/events/api.sx b/lib/events/api.sx
index aa5b2d03..3484f9f4 100644
--- a/lib/events/api.sx
+++ b/lib/events/api.sx
@@ -275,3 +275,55 @@
       ((ev/would-time-conflict? b store actor occ)
         {:status :time-conflict :actor actor :occ-key (ev-occ-key occ)})
       (else (ev/book-occ! b store actor occ)))))
+
+;; ---- whole-series operations ----
+;; Apply a booking action to every occurrence of one event in [ws, we) — e.g.
+;; "RSVP to the whole weekly class". Returns a list of (occ-key status) results,
+;; one per occurrence (empty if the event id is unknown).
+(define
+  ev/book-series!
+  (fn
+    (b store actor event-id ws we)
+    (let
+      ((ev (ev/event-by-id store event-id)))
+      (if
+        (nil? ev)
+        (list)
+        (map
+          (fn (occ) (list (ev-occ-key occ) (get (ev/book-occ! b store actor occ) :status)))
+          (ev-expand ev ws we))))))
+
+;; Cancel `actor` from every occurrence of one event in [ws, we).
+(define
+  ev/cancel-series!
+  (fn
+    (b store actor event-id ws we)
+    (let
+      ((ev (ev/event-by-id store event-id)))
+      (if
+        (nil? ev)
+        (list)
+        (map
+          (fn (occ) (list (ev-occ-key occ) (get (ev/cancel! b (ev-occ-key occ) actor) :status)))
+          (ev-expand ev ws we))))))
+
+;; How many statuses in a series-result list equal `status`.
+(define
+  ev/series-count
+  (fn
+    (results status)
+    (len (filter (fn (r) (= (first (rest r)) status)) results))))
+
+;; The occurrences of one event in [ws, we) that `actor` is booked into.
+(define
+  ev/series-booked
+  (fn
+    (b store actor event-id ws we)
+    (let
+      ((ev (ev/event-by-id store event-id)))
+      (if
+        (nil? ev)
+        (list)
+        (filter
+          (fn (occ) (ev-actor-booked? b (ev-occ-key occ) actor))
+          (ev-expand ev ws we))))))
diff --git a/lib/events/scoreboard.json b/lib/events/scoreboard.json
index a5a30acd..a2395334 100644
--- a/lib/events/scoreboard.json
+++ b/lib/events/scoreboard.json
@@ -1,14 +1,14 @@
 {
   "lang": "events",
-  "total_passed": 332,
+  "total_passed": 341,
   "total_failed": 0,
-  "total": 332,
+  "total": 341,
   "suites": [
     {"name":"calendar","passed":51,"failed":0,"total":51},
     {"name":"timezone","passed":17,"failed":0,"total":17},
     {"name":"ical","passed":21,"failed":0,"total":21},
     {"name":"availability","passed":22,"failed":0,"total":22},
-    {"name":"api","passed":32,"failed":0,"total":32},
+    {"name":"api","passed":41,"failed":0,"total":41},
     {"name":"booking","passed":82,"failed":0,"total":82},
     {"name":"booking-notify","passed":11,"failed":0,"total":11},
     {"name":"ticket","passed":31,"failed":0,"total":31},
@@ -17,5 +17,5 @@
     {"name":"federation","passed":29,"failed":0,"total":29},
     {"name":"integration","passed":8,"failed":0,"total":8}
   ],
-  "generated": "2026-06-07T14:40:54+00:00"
+  "generated": "2026-06-07T15:20:08+00:00"
 }
diff --git a/lib/events/scoreboard.md b/lib/events/scoreboard.md
index b393b5b6..3a4b4e0d 100644
--- a/lib/events/scoreboard.md
+++ b/lib/events/scoreboard.md
@@ -1,6 +1,6 @@
 # events scoreboard
 
-**332 / 332 passing** (0 failure(s)).
+**341 / 341 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -8,7 +8,7 @@
 | timezone | 17 | 17 | ok |
 | ical | 21 | 21 | ok |
 | availability | 22 | 22 | ok |
-| api | 32 | 32 | ok |
+| api | 41 | 41 | ok |
 | booking | 82 | 82 | ok |
 | booking-notify | 11 | 11 | ok |
 | ticket | 31 | 31 | ok |
diff --git a/lib/events/tests/api.sx b/lib/events/tests/api.sx
index fb681f8f..b8ccf25a 100644
--- a/lib/events/tests/api.sx
+++ b/lib/events/tests/api.sx
@@ -319,6 +319,65 @@
             (ev/would-time-conflict? b store (quote zed) ob)
             false))))))
 
+;; ---- whole-series booking ----
+(define
+  ev-api-sr-run-all!
+  (fn
+    ()
+    (let
+      ((b (persist/open))
+        (store
+          (ev/schedule
+            (ev/empty)
+            (quote yoga)
+            (ev-dt 2026 6 1 18 0)
+            60
+            {:freq :weekly :byday (list 0 2) :count 4}
+            20))
+        (ws (ev-date 2026 6 1))
+        (we (ev-date 2026 7 1)))
+      (do
+        (let
+          ((res (ev/book-series! b store (quote nia) (quote yoga) ws we)))
+          (do
+            (ev-api-check! "series booking covers all four occurrences" (len res) 4)
+            (ev-api-check! "all occurrences booked" (ev/series-count res :booked) 4)
+            (ev-api-check!
+              "actor is now booked into the whole series"
+              (len (ev/series-booked b store (quote nia) (quote yoga) ws we))
+              4)))
+        ;; re-booking the series is idempotent
+        (ev-api-check!
+          "re-booking the series is idempotent"
+          (ev/series-count (ev/book-series! b store (quote nia) (quote yoga) ws we) :already)
+          4)
+        ;; cancel the whole series
+        (let
+          ((res (ev/cancel-series! b store (quote nia) (quote yoga) ws we)))
+          (do
+            (ev-api-check! "series cancel reports four cancellations" (ev/series-count res :cancelled) 4)
+            (ev-api-check!
+              "actor booked into nothing after series cancel"
+              (len (ev/series-booked b store (quote nia) (quote yoga) ws we))
+              0)))
+        ;; capacity interacts per-occurrence: fill one occurrence first
+        (let
+          ((b2 (persist/open))
+            (s2
+              (ev/schedule (ev/empty) (quote clinic) (ev-dt 2026 6 1 9 0) 30 {:freq :daily :count 3} 1)))
+          (do
+            (ev/book-occ! b2 s2 (quote x) (ev-occ (quote clinic) (ev-dt 2026 6 2 9 0) 30))
+            (let
+              ((res (ev/book-series! b2 s2 (quote nia) (quote clinic) (ev-date 2026 6 1) (ev-date 2026 6 10))))
+              (do
+                (ev-api-check! "series booking succeeds on free occurrences" (ev/series-count res :booked) 2)
+                (ev-api-check! "series booking hits :full where capacity is taken" (ev/series-count res :full) 1)))))
+        ;; unknown event id
+        (ev-api-check!
+          "series booking an unknown event yields no results"
+          (ev/book-series! b store (quote nia) (quote nope) ws we)
+          (list))))))
+
 (define
   ev-api-tests-run!
   (fn
@@ -329,4 +388,5 @@
       (set! ev-api-failures (list))
       (ev-api-run-all!)
       (ev-api-cf-run-all!)
+      (ev-api-sr-run-all!)
       {:failures ev-api-failures :total (+ ev-api-pass ev-api-fail) :passed ev-api-pass :failed ev-api-fail})))
diff --git a/plans/events-on-sx.md b/plans/events-on-sx.md
index 94a7da04..d7943de6 100644
--- a/plans/events-on-sx.md
+++ b/plans/events-on-sx.md
@@ -18,7 +18,7 @@ capacity rules, transactional booking, and a flow-driven notification dispatcher
 
 ## Status (rolling)
 
-`bash lib/events/conformance.sh` → **332/332** (Phases 1-4 + 11 ext: …e2e delivery, conflict-checked booking, iCalendar export)
+`bash lib/events/conformance.sh` → **341/341** (Phases 1-4 + 12 ext: …conflict-checked booking, iCalendar export, whole-series booking)
 
 ## Ground rules
 
@@ -88,6 +88,13 @@ lib/events/api.sx ── (events/schedule) (events/book) (events/agenda) ──
 
 ## Progress log
 
+- 2026-06-07 — Whole-series booking (extension). `ev/book-series!` /
+  `ev/cancel-series!` apply a booking/cancel to every occurrence of one event
+  in a window (e.g. RSVP the whole weekly class), returning per-occurrence
+  (occ-key status) results; capacity is still enforced per occurrence (some
+  :booked, some :full). Idempotent re-book (all :already). `ev/series-count`
+  (tally a status), `ev/series-booked` (which occurrences the actor holds).
+  +9 tests, 341/341 green. This was the last flagged feature — surface saturated.
 - 2026-06-07 — iCalendar (RFC 5545) export (extension). `ical.sx` serializes
   events to VEVENT / VCALENDAR text for import by standard clients. UTC
   basic-format stamps (YYYYMMDDTHHMM00Z), DURATION (PT#H#M), and the full RRULE