diff --git a/app/controllers/calendar_events_controller.rb b/app/controllers/calendar_events_controller.rb
index ba0e55f..be5c03b 100644
--- a/app/controllers/calendar_events_controller.rb
+++ b/app/controllers/calendar_events_controller.rb
@@ -142,7 +142,8 @@ def apply_calendar_update!(starts:, ends:, title:)
       title: title,
       starts_at: starts,
       ends_at: ends,
-      all_day: @event.all_day
+      all_day: @event.all_day,
+      time_zone: current_user.timezone
     )
 
     if result.nil?
diff --git a/app/controllers/timer_sessions_controller.rb b/app/controllers/timer_sessions_controller.rb
index 3b6069b..2e001c4 100644
--- a/app/controllers/timer_sessions_controller.rb
+++ b/app/controllers/timer_sessions_controller.rb
@@ -19,7 +19,7 @@ def create
     if current_user.hey_connected? && task
       begin
         client = HeyClient.new(current_user)
-        result = client.start_time_track(title: task.title)
+        result = client.start_time_track
         if result.is_a?(Hash) && result["id"].present?
           @timer.update_column(:hey_time_track_id, result["id"].to_s)
         end
@@ -47,7 +47,10 @@ def stop_hey_time_track(timer)
     return if timer.hey_time_track_id.blank?
     return unless current_user.hey_connected?
 
-    HeyClient.new(current_user).stop_time_track(timer.hey_time_track_id)
+    HeyClient.new(current_user).stop_time_track(
+      timer.hey_time_track_id,
+      category_title: timer.task_assignment&.title
+    )
   rescue StandardError => e
     Rails.logger.warn("HEY time track stop failed: #{e.message}")
   end
diff --git a/app/jobs/sync_calendar_events_job.rb b/app/jobs/sync_calendar_events_job.rb
index 3b01871..829f61d 100644
--- a/app/jobs/sync_calendar_events_job.rb
+++ b/app/jobs/sync_calendar_events_job.rb
@@ -70,10 +70,17 @@ def upsert_basecamp(user, entry, week_start, week_end)
 
   def sync_hey(user, week_start, week_end)
     client = HeyClient.new(user)
-    events = client.calendar_events(starts_on: week_start.iso8601, ends_on: week_end.iso8601)
-    if events.is_a?(Array)
-      dedupe_hey_recordings(events).each { |evt| upsert_hey(user, evt) }
+    events = []
+
+    if client.respond_to?(:calendar_week_events)
+      week_rows = client.calendar_week_events(week_start.iso8601)
+      events.concat(week_rows) if week_rows.is_a?(Array)
     end
+
+    recordings = client.calendar_events(starts_on: week_start.iso8601, ends_on: week_end.iso8601)
+    events.concat(recordings) if recordings.is_a?(Array)
+
+    dedupe_hey_recordings(events).each { |evt| upsert_hey(user, evt) }
     reconcile_duplicate_hey_calendar_rows!(user)
     true
   rescue HeyClient::AuthError => e
diff --git a/app/jobs/sync_sometime_todo_to_hey_job.rb b/app/jobs/sync_sometime_todo_to_hey_job.rb
index 4881247..1cb80d7 100644
--- a/app/jobs/sync_sometime_todo_to_hey_job.rb
+++ b/app/jobs/sync_sometime_todo_to_hey_job.rb
@@ -8,14 +8,19 @@ def perform(task_assignment_id)
     user = task.user
     return unless user.hey_connected?
     return unless task.week_bucket == "sometime"
-    return if task.hey_mirrored_todo_id.present?
 
     week_start = task.week_start_date || user.current_week_start
     tz = ActiveSupport::TimeZone[user.timezone] || Time.zone
     anchor = tz.local(week_start.year, week_start.month, week_start.day, 12, 0) + 6.days
+    starts_on = anchor.to_date.iso8601
 
     client = HeyClient.new(user)
-    result = client.create_todo(title: task.title, starts_at: anchor.to_date.iso8601)
+    if task.hey_mirrored_todo_id.present?
+      client.update_todo(task.hey_mirrored_todo_id, title: task.title, starts_at: starts_on)
+      return
+    end
+
+    result = client.create_todo(title: task.title, starts_at: starts_on)
     new_id = extract_todo_id(result)
     return if new_id.blank?
 
diff --git a/app/jobs/sync_timebox_to_hey_job.rb b/app/jobs/sync_timebox_to_hey_job.rb
index 0f8c990..06d2dea 100644
--- a/app/jobs/sync_timebox_to_hey_job.rb
+++ b/app/jobs/sync_timebox_to_hey_job.rb
@@ -14,8 +14,6 @@ def perform(task_assignment_id)
     CalendarEvent.destroy_daybreak_timebox_mirror!(user, task.id)
 
     prev_id = task.hey_calendar_event_id
-    client.delete_timebox_mirror_remote_id(prev_id) if prev_id.present?
-
     cal_id = client.calendar_id_for_timed_writes
     tz_name = user.timezone.presence || "UTC"
     zone = ActiveSupport::TimeZone[tz_name] || Time.zone
@@ -26,13 +24,31 @@ def perform(task_assignment_id)
 
     new_id = nil
     if cal_id.present?
-      new_id = client.create_timed_calendar_event_form(
-        calendar_id: cal_id,
-        title: task.title,
-        local_start: local_start,
-        local_end: local_end,
-        time_zone: tz_name
-      )
+      if prev_id.present?
+        patched = client.update_calendar_event(
+          calendar_id: cal_id,
+          event_id: prev_id,
+          title: task.title,
+          starts_at: local_start,
+          ends_at: local_end,
+          all_day: false,
+          time_zone: tz_name
+        )
+        new_id = patched.presence
+      end
+
+      if new_id.blank?
+        new_id = client.create_timed_calendar_event_form(
+          calendar_id: cal_id,
+          title: task.title,
+          local_start: local_start,
+          local_end: local_end,
+          time_zone: tz_name
+        )
+        if prev_id.present? && new_id.present? && new_id.to_s != prev_id.to_s
+          client.delete_timebox_mirror_remote_id(prev_id)
+        end
+      end
     end
 
     d = task.planned_start_at.in_time_zone(user.timezone).to_date
diff --git a/app/services/hey_client.rb b/app/services/hey_client.rb
index cd22178..a37871a 100644
--- a/app/services/hey_client.rb
+++ b/app/services/hey_client.rb
@@ -157,19 +157,38 @@ def todos
     recordings_calendar_todos(raw)
   end
 
-  # +starts_at+ may be Time or Date; serialized as ISO8601 (hey-sdk OpenAPI: date or time string).
+  # Week period: recurring events are expanded into the occurrences that fall
+  # inside the week. Recordings list a series once, on the day it was created.
+  def calendar_week(date)
+    get("/calendar/weeks/#{date}.json")
+  end
+
+  def calendar_week_events(date)
+    flatten_calendar_period(calendar_week(date))
+  end
+
+  # +starts_at+ is a bare YYYY-MM-DD. An RFC 3339 midnight can land on the
+  # previous day once HEY casts it in the user's zone (hey-sdk CalendarTodos).
   def create_todo(title:, starts_at: nil, ends_at: nil)
     inner = {
       title: title.to_s,
-      starts_at: starts_at.respond_to?(:iso8601) ? starts_at.iso8601 : starts_at.to_s
-    }.compact
-    # Non-standard field; HEY may ignore. Omitted if not set.
-    inner[:ends_at] = ends_at.iso8601 if ends_at.respond_to?(:iso8601)
+      starts_at: coerce_todo_date(starts_at) || Date.current.iso8601
+    }
     post("/calendar/todos.json", { "calendar_todo" => inner })
   end
 
+  def update_todo(todo_id, title: nil, starts_at: nil, focused: nil)
+    changes = {}
+    changes[:title] = title.to_s if title.present?
+    changes[:starts_at] = coerce_todo_date(starts_at) if starts_at.present?
+    changes[:focused] = focused unless focused.nil?
+    return nil if changes.empty?
+
+    patch("/calendar/todos/#{todo_id}.json", { "calendar_todo" => changes })
+  end
+
   def delete_todo(todo_id)
-    delete("/calendar/todos/#{todo_id}")
+    delete("/calendar/todos/#{todo_id}.json")
   end
 
   def complete_todo(todo_id)
@@ -198,11 +217,17 @@ def flatten_calendar_recordings(raw, calendar_id:, color: nil)
         rid = rec["id"]
         next if rid.blank?
 
+        cid = calendar_id.presence
+        if cid.blank? && rec["calendar"].is_a?(Hash)
+          cid = rec.dig("calendar", "id").to_s.presence
+        end
+
         merged = rec.merge(
           "id" => rid.to_s,
-          "hey_calendar_id" => calendar_id
+          "hey_calendar_id" => cid
         )
         merged["calendar_color"] = color if color.present?
+        stamp_hey_event_identity!(merged)
         rows << merged
       end
     end
@@ -217,76 +242,113 @@ def flatten_calendar_recordings(raw, calendar_id:, color: nil)
     rows.uniq { |r| [ r["hey_calendar_id"], r["id"] ] }
   end
 
-  # Synced HEY calendar rows (drag/resize/delete in Daybreak): JSON under /calendars/:id/events…
-  # hey-sdk OpenAPI documents Bearer calendar *writes* for todos (`POST /calendar/todos.json`);
-  # session-only form routes like `POST /calendar/events` return 404 for OAuth clients (see debug H6).
-  def update_calendar_event(calendar_id:, event_id:, title: nil, starts_at: nil, ends_at: nil, all_day: nil)
-    attrs = {}.tap do |h|
-      h[:title] = title if title.present?
-      h[:starts_at] = starts_at.iso8601 if starts_at.respond_to?(:iso8601)
-      h[:ends_at] = ends_at.iso8601 if ends_at.respond_to?(:iso8601)
-      h[:all_day] = all_day unless all_day.nil?
+  # Week/day period payload: { starts_at, ends_at, kind, recordings: { "Calendar::Event" => [...] } }
+  def flatten_calendar_period(raw)
+    return [] if raw.blank?
+    return [] unless raw.is_a?(Hash)
+
+    data = raw.stringify_keys
+    recordings = data["recordings"] || data
+    return [] unless recordings.is_a?(Hash) || recordings.is_a?(Array)
+
+    if recordings.is_a?(Hash)
+      event_keys = recordings.keys.select { |k| k.to_s.match?(/event/i) && !k.to_s.match?(/todo/i) }
+      subset = event_keys.any? ? recordings.slice(*event_keys) : recordings
+      rows = flatten_calendar_recordings(subset, calendar_id: nil)
+      rows.reject! { |r| r["type"].to_s.match?(/todo/i) } if event_keys.empty?
+      rows
+    else
+      flatten_calendar_recordings(recordings, calendar_id: nil)
     end
-    return nil if attrs.empty?
+  end
 
-    patch("/calendars/#{calendar_id}/events/#{event_id}.json", { "calendar_event" => attrs })
+  # Official writes (hey-sdk CalendarEventsService): form to /calendar/events.json
+  # with calendar_event[set_time_zone]=1 so zone names are not dropped.
+  def update_calendar_event(calendar_id:, event_id:, title: nil, starts_at: nil, ends_at: nil, all_day: nil, time_zone: nil)
+    return nil if starts_at.blank? || ends_at.blank?
+
+    ref = parse_event_ref(event_id)
+    tz = time_zone.to_s.presence || @user.timezone.presence || "UTC"
+    pairs = calendar_event_form_pairs(
+      calendar_id: calendar_id,
+      title: title,
+      starts_at: starts_at,
+      ends_at: ends_at,
+      all_day: all_day,
+      time_zone: tz
+    )
+    path = if ref[:occurrence]
+      "/calendar/events/#{ref[:series_id]}/occurrences/#{ref[:date]}.json"
+    else
+      "/calendar/events/#{ref[:series_id]}.json"
+    end
+    meta = form_request(:patch, path, pairs)
+    return nil unless form_write_ok?(meta)
+
+    extract_event_id_from_form_meta(meta).presence || event_id.to_s
   end
 
-  def delete_calendar_event(calendar_id:, event_id:)
-    delete("/calendars/#{calendar_id}/events/#{event_id}.json")
+  def delete_calendar_event(calendar_id: nil, event_id:)
+    ref = parse_event_ref(event_id)
+    path = if ref[:occurrence]
+      "/calendar/events/#{ref[:series_id]}/occurrences/#{ref[:date]}.json"
+    else
+      "/calendar/events/#{ref[:series_id]}"
+    end
+    meta = form_request(:delete, path, nil)
+    return true if form_write_ok?(meta)
+
+    # Last-resort JSON delete for leftover nested-path ids.
+    return false if calendar_id.blank?
+
+    !delete("/calendars/#{calendar_id}/events/#{ref[:series_id]}.json").nil?
   end
 
-  def create_calendar_event(calendar_id:, title:, starts_at:, ends_at:, all_day: false)
-    attrs = {
-      title: title.to_s,
-      starts_at: starts_at.respond_to?(:iso8601) ? starts_at.iso8601 : starts_at.to_s,
-      ends_at: ends_at.respond_to?(:iso8601) ? ends_at.iso8601 : ends_at.to_s,
+  def create_calendar_event(calendar_id:, title:, starts_at:, ends_at:, all_day: false, time_zone: nil)
+    create_timed_calendar_event_form(
+      calendar_id: calendar_id,
+      title: title,
+      local_start: starts_at,
+      local_end: ends_at,
+      time_zone: time_zone || @user.timezone.presence || "UTC",
       all_day: all_day
-    }
-    post("/calendars/#{calendar_id}/events.json", { "calendar_event" => attrs })
+    )
   end
 
-  # Timed HEY calendar mirror: try hey-sdk browser form first, then JSON create (runtime: OAuth gets 404 on form — debug H7).
-  # Form matches go/pkg/hey/calendar_events.go; JSON matches #create_calendar_event for Bearer.
-  def create_timed_calendar_event_form(calendar_id:, title:, local_start:, local_end:, time_zone:)
-    tz = time_zone.to_s.presence || "UTC"
-    ls = local_start
-    le = local_end
-    starts_date = ls.to_date.iso8601
-    ends_date = le.to_date.iso8601
-    form_pairs = [
-      [ "calendar_event[calendar_id]", calendar_id.to_s ],
-      [ "calendar_event[summary]", title.to_s ],
-      [ "calendar_event[starts_at]", starts_date ],
-      [ "calendar_event[ends_at]", ends_date ],
-      [ "calendar_event[all_day]", "0" ],
-      [ "calendar_event[starts_at_time]", "#{ls.strftime("%H:%M")}:00" ],
-      [ "calendar_event[ends_at_time]", "#{le.strftime("%H:%M")}:00" ],
-      [ "calendar_event[starts_at_time_zone_name]", tz ],
-      [ "calendar_event[ends_at_time_zone_name]", tz ]
-    ]
-    meta = form_request(:post, "/calendar/events", form_pairs)
-    id = extract_form_redirect_event_id(meta)
-    return id if id.present?
-
-    json_body = {
-      "calendar_event" => {
-        "title" => title.to_s,
-        "starts_at" => ls.iso8601,
-        "ends_at" => le.iso8601,
-        "all_day" => false
-      }
-    }
-    jmeta = json_post_with_meta("/calendars/#{calendar_id}/events.json", json_body)
-    return nil unless jmeta[:success]
-
-    extract_json_calendar_event_id(jmeta[:json])
+  def create_timed_calendar_event_form(calendar_id:, title:, local_start:, local_end:, time_zone:, all_day: false)
+    pairs = calendar_event_form_pairs(
+      calendar_id: calendar_id,
+      title: title,
+      starts_at: local_start,
+      ends_at: local_end,
+      all_day: all_day,
+      time_zone: time_zone
+    )
+    meta = form_request(:post, "/calendar/events.json", pairs)
+    extract_event_id_from_form_meta(meta)
   end
 
   def delete_calendar_event_form(event_id)
-    meta = form_request(:delete, "/calendar/events/#{event_id}", nil)
-    code = meta[:code].to_i
-    code == 302 || code == 303 || (code >= 200 && code < 300)
+    delete_calendar_event(event_id: event_id)
+  end
+
+  # Official calendar delete first; leftover sometime-todo mirrors fall back to todo delete.
+  def delete_timebox_mirror_remote_id(remote_id)
+    return if remote_id.blank?
+
+    cal_ok = false
+    begin
+      cal_ok = delete_calendar_event(event_id: remote_id)
+    rescue StandardError
+      cal_ok = false
+    end
+    return if cal_ok
+
+    begin
+      delete_todo(remote_id)
+    rescue StandardError
+      nil
+    end
   end
 
   # Habits
@@ -298,15 +360,23 @@ def complete_habit(day, habit_id)
   # Time tracking
 
   def current_time_track
-    get("/calendar/ongoing_time_track.json")
+    get("/calendar/ongoing_time_track.json", allow: [ 404 ])
   end
 
+  # HEY ignores the start body and starts a track with defaults. 409 means a
+  # track is already running — adopt GET /calendar/ongoing_time_track.json.
   def start_time_track(title: nil)
-    post("/calendar/ongoing_time_track.json", { title: title }.compact)
+    data = post("/calendar/ongoing_time_track.json", allow: [ 409 ])
+    return current_time_track if @last_status_code == 409
+    return data if data.is_a?(Hash) && data["id"].present?
+
+    current_time_track || data
   end
 
-  def stop_time_track(time_track_id)
-    put("/calendar/time_tracks/#{time_track_id}.json", { ends_at: Time.current.iso8601 })
+  def stop_time_track(time_track_id, category_title: nil)
+    inner = { ends_at: Time.current.iso8601 }
+    inner[:category_title] = category_title if category_title.present?
+    put("/calendar/time_tracks/#{time_track_id}.json", { "calendar_time_track" => inner })
   end
 
   # Journal
@@ -339,11 +409,11 @@ def imbox
   end
 
   def reply_later
-    fetch_box("/reply_later.json")
+    fetch_box("/laterbox.json")
   end
 
   def set_aside
-    fetch_box("/set_aside.json")
+    fetch_box("/asidebox.json")
   end
 
   def feed
@@ -351,13 +421,14 @@ def feed
   end
 
   def paper_trail
-    fetch_box("/paper_trail.json")
+    fetch_box("/trailbox.json")
   end
 
   private
 
-  # Returns postings from a BoxShowResponse, following next_history_url until +max_postings+.
-  # Canonical paths per hey-sdk openapi (not /laterbox.json etc.).
+  # Returns postings from a BoxShowResponse, following next_history_url or a
+  # same-origin Link: rel=next header (geared_pagination) until +max_postings+.
+  # Canonical paths per hey-sdk: /laterbox.json, /asidebox.json, /trailbox.json.
   # nil on first-request failure; [] if the box is empty.
   def fetch_box(initial_path, max_postings: 200)
     all = []
@@ -378,9 +449,11 @@ def fetch_box(initial_path, max_postings: 200)
       break if all.size >= max_postings
 
       nxt = data["next_history_url"].presence
+      nxt ||= next_path_from_link_header(@last_link_header)
       break if nxt.blank?
 
-      next_path = path_from_hey_url(nxt) || break
+      next_path = path_from_hey_url(nxt) || nxt
+      break if next_path.blank?
     end
     all.first(max_postings)
   end
@@ -449,57 +522,27 @@ def recordings_calendar_todos(raw)
     end
   end
 
-  def get(path)
-    request(:get, path)
-  end
-
-  def post(path, body = nil)
-    request(:post, path, body)
+  def get(path, allow: [])
+    request(:get, path, allow: allow)
   end
 
-  def put(path, body)
-    request(:put, path, body)
+  def post(path, body = nil, allow: [])
+    request(:post, path, body, allow: allow)
   end
 
-  def patch(path, body)
-    request(:patch, path, body)
+  def put(path, body, allow: [])
+    request(:put, path, body, allow: allow)
   end
 
-  def delete(path)
-    request(:delete, path)
+  def patch(path, body, allow: [])
+    request(:patch, path, body, allow: allow)
   end
 
-  # Removes a timebox mirror id: form calendar delete, JSON calendar delete, then legacy todo mirrors.
-  def delete_timebox_mirror_remote_id(remote_id)
-    return if remote_id.blank?
-
-    cal_ok = false
-    begin
-      cal_ok = delete_calendar_event_form(remote_id)
-    rescue StandardError
-      cal_ok = false
-    end
-    return if cal_ok
-
-    cid = calendar_id_for_timed_writes
-    if cid.present?
-      json_del = nil
-      begin
-        json_del = delete_calendar_event(calendar_id: cid, event_id: remote_id)
-      rescue StandardError
-        json_del = nil
-      end
-      return unless json_del.nil?
-    end
-
-    begin
-      delete_todo(remote_id)
-    rescue StandardError
-      nil
-    end
+  def delete(path, allow: [])
+    request(:delete, path, allow: allow)
   end
 
-  def request(method, path, body = nil)
+  def request(method, path, body = nil, allow: [])
     ensure_fresh_token!
 
     uri = URI("#{BASE_API_URL}#{path}")
@@ -520,6 +563,8 @@ def request(method, path, body = nil)
     req.body = body.to_json if body
 
     response = http_start(uri) { |http| http.request(req) }
+    @last_status_code = response.code.to_i
+    @last_link_header = response["Link"]
 
     case response
     when Net::HTTPSuccess
@@ -533,8 +578,10 @@ def request(method, path, body = nil)
 
       JSON.parse(body_str)
     when Net::HTTPUnauthorized
-      refresh_and_retry!(method, path, body)
+      refresh_and_retry!(method, path, body, allow: allow)
     else
+      return nil if allow.include?(@last_status_code)
+
       Rails.logger.error("HEY API error: #{response.code} #{response.body}")
       nil
     end
@@ -562,9 +609,9 @@ def perform_token_refresh!
     end
   end
 
-  def refresh_and_retry!(method, path, body)
+  def refresh_and_retry!(method, path, body, allow: [])
     perform_token_refresh!
-    request(method, path, body)
+    request(method, path, body, allow: allow)
   rescue AuthError
     raise AuthError, "HEY session expired. Reconnect from Settings."
   rescue StandardError => e
@@ -587,7 +634,7 @@ def form_request(method, path, form_pairs)
     raise
   rescue StandardError => e
     Rails.logger.error("HEY form request error: #{e.class} #{e.message}")
-    { code: 0, location: nil, unauthorized: false }
+    { code: 0, location: nil, body: nil, unauthorized: false, success: false }
   end
 
   def perform_form_http(method, path, form_pairs)
@@ -609,10 +656,13 @@ def perform_form_http(method, path, form_pairs)
     end
 
     res = http_start(uri) { |http| http.request(req) }
+    code = res.code.to_i
     {
-      code: res.code.to_i,
+      code: code,
       location: res["Location"],
-      unauthorized: res.is_a?(Net::HTTPUnauthorized)
+      body: res.body.to_s,
+      unauthorized: res.is_a?(Net::HTTPUnauthorized),
+      success: res.is_a?(Net::HTTPSuccess) || [ 302, 303 ].include?(code)
     }
   end
 
@@ -667,6 +717,115 @@ def single_json_post(path, body)
   def extract_json_calendar_event_id(data)
     return nil unless data.is_a?(Hash)
 
-    data["id"]&.to_s || data.dig("calendar_event", "id")&.to_s
+    data["id"]&.to_s || data.dig("calendar_event", "id")&.to_s || data.dig("recording", "id")&.to_s
+  end
+
+  def extract_event_id_from_form_meta(meta)
+    return nil unless form_write_ok?(meta)
+
+    body = meta[:body].to_s.strip
+    if body.present?
+      parsed = JSON.parse(body) rescue nil
+      id = extract_json_calendar_event_id(parsed)
+      return id if id.present?
+    end
+    extract_form_redirect_event_id(meta)
+  end
+
+  def form_write_ok?(meta)
+    return false if meta.nil?
+
+    code = meta[:code].to_i
+    meta[:success] == true || (code >= 200 && code < 300) || [ 302, 303 ].include?(code)
+  end
+
+  def calendar_event_form_pairs(calendar_id:, title:, starts_at:, ends_at:, all_day:, time_zone:)
+    tz = time_zone.to_s.presence || "UTC"
+    ls = starts_at
+    le = ends_at || starts_at
+    pairs = [
+      [ "calendar_event[calendar_id]", calendar_id.to_s ],
+      [ "calendar_event[summary]", title.to_s ],
+      [ "calendar_event[starts_at]", date_only(ls) ],
+      [ "calendar_event[ends_at]", date_only(le) ]
+    ]
+    if all_day
+      pairs << [ "calendar_event[all_day]", "1" ]
+    else
+      pairs << [ "calendar_event[all_day]", "0" ]
+      pairs << [ "calendar_event[starts_at_time]", clock_time(ls) ]
+      pairs << [ "calendar_event[ends_at_time]", clock_time(le) ]
+      pairs << [ "calendar_event[set_time_zone]", "1" ]
+      pairs << [ "calendar_event[starts_at_time_zone_name]", tz ]
+      pairs << [ "calendar_event[ends_at_time_zone_name]", tz ]
+    end
+    pairs
+  end
+
+  def date_only(value)
+    return value.to_date.iso8601 if value.respond_to?(:to_date)
+
+    value.to_s[0, 10]
+  end
+
+  def clock_time(value)
+    return "#{value.strftime("%H:%M")}:00" if value.respond_to?(:strftime)
+
+    str = value.to_s
+    if (m = str.match(/T(\d{2}:\d{2})/))
+      return "#{m[1]}:00"
+    end
+
+    "00:00:00"
+  end
+
+  def coerce_todo_date(value)
+    return nil if value.blank?
+    return value if value.is_a?(String) && value.match?(/\A\d{4}-\d{2}-\d{2}\z/)
+    return value.to_date.iso8601 if value.respond_to?(:to_date)
+
+    Date.iso8601(value.to_s).iso8601
+  rescue ArgumentError
+    value.to_s[0, 10]
+  end
+
+  EVENT_OCCURRENCE_REF = /\A(\d+):(\d{4}-\d{2}-\d{2})\z/
+
+  def parse_event_ref(event_id)
+    if event_id.to_s =~ EVENT_OCCURRENCE_REF
+      { series_id: ::Regexp.last_match(1), date: ::Regexp.last_match(2), occurrence: true }
+    else
+      { series_id: event_id.to_s, date: nil, occurrence: false }
+    end
+  end
+
+  def stamp_hey_event_identity!(rec)
+    occ = rec["occurrence_id"] || rec["occurrenceId"]
+    parent = rec["parent_id"] || rec["parentId"]
+    parent ||= rec.dig("parent", "id") if rec["parent"].is_a?(Hash)
+    series_id = (parent.presence || rec["id"]).to_s
+    starts = rec["starts_at"] || rec["startsAt"]
+
+    if occ.present? && series_id.present? && starts.present?
+      date = begin
+        Time.zone.parse(starts.to_s).to_date.iso8601
+      rescue ArgumentError, TypeError
+        nil
+      end
+      rec["id"] = "#{series_id}:#{date}" if date
+    end
+    rec
+  end
+
+  def next_path_from_link_header(link)
+    return nil if link.blank?
+
+    part = link.to_s.split(",").map(&:strip).find do |p|
+      p.include?('rel="next"') || p.include?("rel=next") || p.include?("rel='next'")
+    end
+    return nil unless part
+
+    url = part[/<([^>]+)>/, 1]
+    path_from_hey_url(url) || url
   end
 end
diff --git a/app/views/hey_connections/new.html.erb b/app/views/hey_connections/new.html.erb
index 2b67393..4acf2b6 100644
--- a/app/views/hey_connections/new.html.erb
+++ b/app/views/hey_connections/new.html.erb
@@ -12,8 +12,7 @@
       </div>
       <h1 class="connect-hey__title">Connect HEY</h1>
       <p class="connect-hey__subtitle">
-        Install the official <code>hey</code> CLI once, grab a token, paste it here.
-        You need <strong>Go 1.26 or newer</strong> on your machine for every install path below.
+        Install the official <code>hey</code> CLI, grab a token, paste it here.
       </p>
     </div>
 
@@ -41,65 +40,39 @@
         <div class="connect-hey__step-body">
           <div class="connect-hey__step-label">Install the HEY CLI <span class="connect-hey__step-note">(skip if <code>hey</code> already works)</span></div>
           <p class="connect-hey__step-hint connect-hey__step-hint--lead">
-            The old Homebrew formula (<code>brew install basecamp/hey/hey</code>) is dead — the tap repo was removed. HEY’s CLI is Go-based; you need <strong>Go 1.26+</strong>. Pick one path:
+            Official installer from HEY — downloads the signed release for your platform:
           </p>
 
-          <div class="connect-hey__install-label">Recommended — macOS + Homebrew</div>
-          <div class="connect-hey__cmd-row connect-hey__cmd-row--multiline">
-            <code class="connect-hey__cmd connect-hey__cmd--multiline" id="cmd-macos-quick">brew install go
-go version   # must be 1.26+
-go install github.com/basecamp/hey-cli/cmd/hey@latest
-export PATH="$(go env GOPATH)/bin:$PATH"
-hey version</code>
-            <button type="button" class="connect-hey__copy-btn connect-hey__copy-btn--top" data-action="clipboard#copy" data-clipboard-source-param="cmd-macos-quick" title="Copy">
+          <div class="connect-hey__install-label">macOS / Linux / WSL2</div>
+          <div class="connect-hey__cmd-row">
+            <code class="connect-hey__cmd" id="cmd-macos-quick">curl -fsSL https://hey.com/install-cli | bash</code>
+            <button type="button" class="connect-hey__copy-btn" data-action="clipboard#copy" data-clipboard-source-param="cmd-macos-quick" title="Copy">
               <span class="connect-hey__copy-icon" data-clipboard-target="icon" data-id="cmd-macos-quick">
                 <svg viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><rect x="4" y="4" width="9" height="11" rx="1.5"/><path d="M4 4V3a1 1 0 0 1 1-1h6a1 1 0 0 1 1 1v1"/></svg>
               </span>
               <span class="connect-hey__copy-text" data-clipboard-target="label" data-id="cmd-macos-quick">Copy</span>
             </button>
           </div>
-          <p class="connect-hey__step-hint">Add the <code>export PATH=…</code> line to <code>~/.zshrc</code> so new terminals find <code>hey</code>.</p>
 
-          <div class="connect-hey__install-label">Already have Go 1.26+?</div>
+          <div class="connect-hey__install-label">Homebrew</div>
           <div class="connect-hey__cmd-row">
-            <code class="connect-hey__cmd" id="cmd-go-install">go install github.com/basecamp/hey-cli/cmd/hey@latest</code>
-            <button type="button" class="connect-hey__copy-btn" data-action="clipboard#copy" data-clipboard-source-param="cmd-go-install" title="Copy">
-              <span class="connect-hey__copy-icon" data-clipboard-target="icon" data-id="cmd-go-install">
-                <svg viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><rect x="4" y="4" width="9" height="11" rx="1.5"/><path d="M4 4V3a1 1 0 0 1 1-1h6a1 1 0 0 1 1 1v1"/></svg>
-              </span>
-              <span class="connect-hey__copy-text" data-clipboard-target="label" data-id="cmd-go-install">Copy</span>
-            </button>
-          </div>
-          <p class="connect-hey__step-hint">Then <code>export PATH="$(go env GOPATH)/bin:$PATH"</code>. No Go? <a href="https://go.dev/dl/" class="connect-hey__link" target="_blank" rel="noopener">go.dev/dl</a>.</p>
-
-          <div class="connect-hey__install-label">No mise, no sudo — build in the repo folder</div>
-          <div class="connect-hey__cmd-row connect-hey__cmd-row--multiline">
-            <code class="connect-hey__cmd connect-hey__cmd--multiline" id="cmd-install-src">git clone https://github.com/basecamp/hey-cli.git
-cd hey-cli
-go build -o ./hey ./cmd/hey
-./hey version</code>
-            <button type="button" class="connect-hey__copy-btn connect-hey__copy-btn--top" data-action="clipboard#copy" data-clipboard-source-param="cmd-install-src" title="Copy">
-              <span class="connect-hey__copy-icon" data-clipboard-target="icon" data-id="cmd-install-src">
+            <code class="connect-hey__cmd" id="cmd-brew-cask">brew install --cask basecamp/tap/hey</code>
+            <button type="button" class="connect-hey__copy-btn" data-action="clipboard#copy" data-clipboard-source-param="cmd-brew-cask" title="Copy">
+              <span class="connect-hey__copy-icon" data-clipboard-target="icon" data-id="cmd-brew-cask">
                 <svg viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><rect x="4" y="4" width="9" height="11" rx="1.5"/><path d="M4 4V3a1 1 0 0 1 1-1h6a1 1 0 0 1 1 1v1"/></svg>
               </span>
-              <span class="connect-hey__copy-text" data-clipboard-target="label" data-id="cmd-install-src">Copy</span>
+              <span class="connect-hey__copy-text" data-clipboard-target="label" data-id="cmd-brew-cask">Copy</span>
             </button>
           </div>
-          <p class="connect-hey__step-hint">Use <code>./hey auth login</code> and <code>./hey auth token</code> from that directory, or move <code>./hey</code> onto your PATH.</p>
 
           <details class="connect-hey__details">
-            <summary class="connect-hey__details-summary">Stuck? Common errors</summary>
-            <ul class="connect-hey__details-list">
-              <li><code>command not found: go</code> — Install Go from <a href="https://go.dev/dl/" class="connect-hey__link" target="_blank" rel="noopener">go.dev/dl</a> or run <code>brew install go</code>.</li>
-              <li><code>go.mod requires Go ≥1.26</code> — Upgrade Go (<code>brew upgrade go</code> or a newer installer).</li>
-              <li><code>hey: command not found</code> after <code>go install</code> — Run <code>export PATH="$(go env GOPATH)/bin:$PATH"</code> or use the <code>./hey</code> build path above.</li>
-              <li><code>command not found: mise</code> — Skip mise; use the blocks above instead.</li>
-            </ul>
+            <summary class="connect-hey__details-summary">Other install paths</summary>
+            <p class="connect-hey__step-hint">Windows (PowerShell): <code>irm https://hey.com/install-cli.ps1 | iex</code></p>
+            <p class="connect-hey__step-hint">From source (Go 1.26+): <code>go install github.com/basecamp/hey-cli/cmd/hey@latest</code></p>
+            <p class="connect-hey__step-hint">
+              <a href="https://github.com/basecamp/hey-cli#install" class="connect-hey__link" target="_blank" rel="noopener">hey-cli README</a>
+            </p>
           </details>
-
-          <p class="connect-hey__step-hint">
-            <a href="https://github.com/basecamp/hey-cli#install" class="connect-hey__link" target="_blank" rel="noopener">hey-cli README</a> (upstream)
-          </p>
         </div>
       </li>
 
@@ -116,7 +89,7 @@ go build -o ./hey ./cmd/hey
               <span class="connect-hey__copy-text" data-clipboard-target="label" data-id="cmd-login">Copy</span>
             </button>
           </div>
-          <p class="connect-hey__step-hint">Opens your browser — sign in with HEY. If you only built <code>./hey</code> in step 1, run <code>./hey auth login</code> from that folder instead.</p>
+          <p class="connect-hey__step-hint">Opens your browser — sign in with HEY. <code>hey login</code> is an alias.</p>
         </div>
       </li>
 
@@ -133,7 +106,7 @@ go build -o ./hey ./cmd/hey
               <span class="connect-hey__copy-text" data-clipboard-target="label" data-id="cmd-token">Copy</span>
             </button>
           </div>
-          <p class="connect-hey__step-hint">On Linux use <code>hey auth token | xclip -selection clipboard</code>. With a local <code>./hey</code> binary: <code>./hey auth token | pbcopy</code>.</p>
+          <p class="connect-hey__step-hint">On Linux use <code>hey auth token | xclip -selection clipboard</code>.</p>
         </div>
       </li>
 
diff --git a/test/jobs/sync_calendar_events_job_test.rb b/test/jobs/sync_calendar_events_job_test.rb
index 97d28f8..3f3aea8 100644
--- a/test/jobs/sync_calendar_events_job_test.rb
+++ b/test/jobs/sync_calendar_events_job_test.rb
@@ -23,6 +23,7 @@ def with_hey_client(client)
   test "sync_hey uses provided week_start for calendar_events window" do
     seen = []
     client = Object.new
+    client.define_singleton_method(:calendar_week_events) { |*| [] }
     client.define_singleton_method(:calendar_events) do |starts_on:, ends_on:|
       seen << [ starts_on, ends_on ]
       []
@@ -39,6 +40,7 @@ def with_hey_client(client)
 
   test "upserts hey event with camelCase keys" do
     client = Object.new
+    client.define_singleton_method(:calendar_week_events) { |*| [] }
     client.define_singleton_method(:calendar_events) do |starts_on:, ends_on:|
       [
         {
@@ -83,6 +85,7 @@ def with_hey_client(client)
     )
 
     client = Object.new
+    client.define_singleton_method(:calendar_week_events) { |*| [] }
     client.define_singleton_method(:calendar_events) { |**_| [] }
 
     with_hey_client(client) do
@@ -94,6 +97,7 @@ def with_hey_client(client)
 
   test "dedupes hey recordings that share title and time range but differ by calendar or id" do
     client = Object.new
+    client.define_singleton_method(:calendar_week_events) { |*| [] }
     client.define_singleton_method(:calendar_events) do |starts_on:, ends_on:|
       [
         {
@@ -127,6 +131,7 @@ def with_hey_client(client)
 
   test "upserts hey events with completed_at from flattened recordings" do
     client = Object.new
+    client.define_singleton_method(:calendar_week_events) { |*| [] }
     client.define_singleton_method(:calendar_events) do |starts_on:, ends_on:|
       [
         {
@@ -151,4 +156,32 @@ def with_hey_client(client)
     assert_equal "owner-99", ev.hey_calendar_id
     assert ev.completed_at.present?
   end
+
+  test "upserts expanded recurring occurrence from calendar_week_events" do
+    week = @week
+    client = Object.new
+    client.define_singleton_method(:calendar_week_events) do |date|
+      raise "unexpected week #{date}" unless date == week.iso8601
+      [
+        {
+          "id" => "88:2026-04-15",
+          "hey_calendar_id" => "cal-1",
+          "title" => "Weekly standup",
+          "starts_at" => "2026-04-15T15:00:00Z",
+          "ends_at" => "2026-04-15T15:30:00Z",
+          "all_day" => false,
+          "occurrence_id" => "_"
+        }
+      ]
+    end
+    client.define_singleton_method(:calendar_events) { |**_| [] }
+
+    with_hey_client(client) do
+      SyncCalendarEventsJob.perform_now(@user.id, week_start: @week.iso8601)
+    end
+
+    ev = @user.calendar_events.find_by(external_id: "88:2026-04-15", source: :hey)
+    assert ev
+    assert_equal "Weekly standup", ev.title
+  end
 end
diff --git a/test/jobs/sync_sometime_todo_to_hey_job_test.rb b/test/jobs/sync_sometime_todo_to_hey_job_test.rb
index c0c5aa9..04f771d 100644
--- a/test/jobs/sync_sometime_todo_to_hey_job_test.rb
+++ b/test/jobs/sync_sometime_todo_to_hey_job_test.rb
@@ -43,18 +43,27 @@ def with_hey_client(client)
     assert_equal "todo-remote-1", @task.reload.hey_mirrored_todo_id
   end
 
-  test "skips when mirrored id already set" do
+  test "updates existing mirrored todo instead of creating another" do
     @task.update_column(:hey_mirrored_todo_id, "existing")
 
-    called = false
+    created = false
+    updated = nil
     client = Object.new
-    client.define_singleton_method(:create_todo) { |**_| called = true }
+    client.define_singleton_method(:create_todo) { |**_| created = true }
+    client.define_singleton_method(:update_todo) do |id, **kw|
+      updated = { id: id, **kw }
+      {}
+    end
 
     with_hey_client(client) do
       SyncSometimeTodoToHeyJob.perform_now(@task.id)
     end
 
-    assert_equal false, called
+    assert_equal false, created
+    assert_equal "existing", updated[:id]
+    assert_equal "Sometime task", updated[:title]
+    assert_equal "2026-04-19", updated[:starts_at]
+    assert_equal "existing", @task.reload.hey_mirrored_todo_id
   end
 
   test "creates todo without hey_app_url using week end anchor date" do
diff --git a/test/jobs/sync_timebox_to_hey_job_test.rb b/test/jobs/sync_timebox_to_hey_job_test.rb
index 3912a05..391ed9d 100644
--- a/test/jobs/sync_timebox_to_hey_job_test.rb
+++ b/test/jobs/sync_timebox_to_hey_job_test.rb
@@ -23,10 +23,19 @@ def create_timed_calendar_event_form(calendar_id:, title:, local_start:, local_e
       remote_id
     end
 
+    def update_calendar_event(**kwargs)
+      (@event_updates ||= []) << kwargs
+      kwargs[:event_id]
+    end
+
     def event_creates
       @event_creates ||= []
     end
 
+    def event_updates
+      @event_updates ||= []
+    end
+
     def mirror_deletes
       @mirror_deletes ||= []
     end
@@ -62,18 +71,32 @@ def mirror_deletes
     HeyClient.define_singleton_method(:new, @orig_hey_new)
   end
 
-  test "replaces existing HEY mirror by delete then create timed calendar event" do
+  test "patches existing HEY mirror instead of delete-and-recreate" do
+    SyncTimeboxToHeyJob.perform_now(@task.id)
+
+    assert_empty @hey_fake.mirror_deletes
+    assert_empty @hey_fake.event_creates
+    assert_equal 1, @hey_fake.event_updates.size
+    u = @hey_fake.event_updates.last
+    assert_equal "cal-default", u[:calendar_id]
+    assert_equal "old-event-id", u[:event_id]
+    assert_equal "Boxed", u[:title]
+    assert_equal "America/Los_Angeles", u[:time_zone]
+    assert_equal "old-event-id", @task.reload.hey_calendar_event_id
+    assert_not @user.calendar_events.exists?(source: :daybreak, external_id: CalendarEvent.daybreak_timebox_external_id(@task.id))
+  end
+
+  test "creates a new event when existing mirror PATCH fails" do
+    @hey_fake.define_singleton_method(:update_calendar_event) do |**kwargs|
+      (@event_updates ||= []) << kwargs
+      nil
+    end
+
     SyncTimeboxToHeyJob.perform_now(@task.id)
 
-    assert_equal %w[old-event-id], @hey_fake.mirror_deletes
     assert_equal 1, @hey_fake.event_creates.size
-    c = @hey_fake.event_creates.last
-    assert_equal "cal-default", c[:calendar_id]
-    assert_equal "Boxed", c[:title]
-    assert_equal "America/Los_Angeles", c[:time_zone]
-    assert_operator c[:local_end], :>, c[:local_start]
+    assert_equal %w[old-event-id], @hey_fake.mirror_deletes
     assert_equal "event-remote-new", @task.reload.hey_calendar_event_id
-    assert_not @user.calendar_events.exists?(source: :daybreak, external_id: CalendarEvent.daybreak_timebox_external_id(@task.id))
   end
 
   test "creates calendar event when no prior mirror id" do
diff --git a/test/services/hey_client_test.rb b/test/services/hey_client_test.rb
index 810f8c3..2696be5 100644
--- a/test/services/hey_client_test.rb
+++ b/test/services/hey_client_test.rb
@@ -13,7 +13,7 @@ class HeyClientTest < ActiveSupport::TestCase
   test "write_journal sends calendar_journal_entry envelope per HEY API" do
     client = HeyClient.new(@user)
     captured = nil
-    client.define_singleton_method(:request) do |method, path, body|
+    client.define_singleton_method(:request) do |method, path, body = nil, allow: []|
       captured = { method: method, path: path, body: body }
       {}
     end
@@ -181,4 +181,264 @@ class HeyClientTest < ActiveSupport::TestCase
     assert_equal 2, rows.size
     assert_equal %w[1 2], rows.map { |r| r["id"] }.sort
   end
+
+  test "create_todo sends bare YYYY-MM-DD on calendar_todo" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:request) do |method, path, body = nil, allow: []|
+      captured = { method: method, path: path, body: body }
+      { "id" => 12 }
+    end
+
+    client.create_todo(title: "Buy milk", starts_at: Date.new(2026, 4, 19))
+
+    assert_equal :post, captured[:method]
+    assert_equal "/calendar/todos.json", captured[:path]
+    assert_equal(
+      { "calendar_todo" => { title: "Buy milk", starts_at: "2026-04-19" } },
+      captured[:body]
+    )
+  end
+
+  test "update_todo patches official todos.json path and omits empty fields" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:request) do |method, path, body = nil, allow: []|
+      captured = { method: method, path: path, body: body }
+      {}
+    end
+
+    client.update_todo("77", title: "Renamed")
+
+    assert_equal :patch, captured[:method]
+    assert_equal "/calendar/todos/77.json", captured[:path]
+    assert_equal({ "calendar_todo" => { title: "Renamed" } }, captured[:body])
+  end
+
+  test "delete_todo uses .json suffix" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:request) do |method, path, body = nil, allow: []|
+      captured = { method: method, path: path }
+      {}
+    end
+
+    client.delete_todo("9")
+
+    assert_equal :delete, captured[:method]
+    assert_equal "/calendar/todos/9.json", captured[:path]
+  end
+
+  test "create_timed_calendar_event_form posts /calendar/events.json with set_time_zone" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:form_request) do |method, path, pairs|
+      captured = { method: method, path: path, pairs: pairs }
+      { code: 201, body: { "id" => 55 }.to_json, location: nil, unauthorized: false, success: true }
+    end
+
+    zone = ActiveSupport::TimeZone["America/Los_Angeles"]
+    id = client.create_timed_calendar_event_form(
+      calendar_id: "42",
+      title: "Focus",
+      local_start: zone.local(2026, 4, 13, 14, 0),
+      local_end: zone.local(2026, 4, 13, 15, 0),
+      time_zone: "America/Los_Angeles"
+    )
+
+    assert_equal "55", id
+    assert_equal :post, captured[:method]
+    assert_equal "/calendar/events.json", captured[:path]
+    assert_includes captured[:pairs], [ "calendar_event[set_time_zone]", "1" ]
+    assert_includes captured[:pairs], [ "calendar_event[starts_at_time_zone_name]", "America/Los_Angeles" ]
+    assert_includes captured[:pairs], [ "calendar_event[starts_at]", "2026-04-13" ]
+    assert_includes captured[:pairs], [ "calendar_event[starts_at_time]", "14:00:00" ]
+  end
+
+  test "create_timed_calendar_event_form falls back to redirect id" do
+    client = HeyClient.new(@user)
+    client.define_singleton_method(:form_request) do |_method, _path, _pairs|
+      { code: 302, body: "", location: "/calendar/events/99", unauthorized: false, success: true }
+    end
+
+    zone = ActiveSupport::TimeZone["UTC"]
+    id = client.create_timed_calendar_event_form(
+      calendar_id: "1",
+      title: "X",
+      local_start: zone.local(2026, 4, 13, 10, 0),
+      local_end: zone.local(2026, 4, 13, 11, 0),
+      time_zone: "UTC"
+    )
+
+    assert_equal "99", id
+  end
+
+  test "update_calendar_event patches official events.json path" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:form_request) do |method, path, pairs|
+      captured = { method: method, path: path, pairs: pairs }
+      { code: 200, body: { "id" => 8 }.to_json, location: nil, unauthorized: false, success: true }
+    end
+
+    zone = ActiveSupport::TimeZone["UTC"]
+    id = client.update_calendar_event(
+      calendar_id: "3",
+      event_id: "8",
+      title: "Meet",
+      starts_at: zone.local(2026, 4, 13, 9, 0),
+      ends_at: zone.local(2026, 4, 13, 10, 0),
+      all_day: false,
+      time_zone: "UTC"
+    )
+
+    assert_equal "8", id
+    assert_equal :patch, captured[:method]
+    assert_equal "/calendar/events/8.json", captured[:path]
+    assert_includes captured[:pairs], [ "calendar_event[set_time_zone]", "1" ]
+  end
+
+  test "update_calendar_event routes occurrence ids to occurrences endpoint" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:form_request) do |method, path, _pairs|
+      captured = { method: method, path: path }
+      { code: 200, body: { "id" => 88 }.to_json, location: nil, unauthorized: false, success: true }
+    end
+
+    zone = ActiveSupport::TimeZone["UTC"]
+    client.update_calendar_event(
+      calendar_id: "3",
+      event_id: "88:2026-04-15",
+      title: "Weekly",
+      starts_at: zone.local(2026, 4, 15, 9, 0),
+      ends_at: zone.local(2026, 4, 15, 10, 0),
+      all_day: false,
+      time_zone: "UTC"
+    )
+
+    assert_equal "/calendar/events/88/occurrences/2026-04-15.json", captured[:path]
+  end
+
+  test "delete_calendar_event uses official form delete path" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:form_request) do |method, path, _pairs|
+      captured = { method: method, path: path }
+      { code: 204, body: "", location: nil, unauthorized: false, success: true }
+    end
+
+    assert client.delete_calendar_event(calendar_id: "3", event_id: "8")
+    assert_equal :delete, captured[:method]
+    assert_equal "/calendar/events/8", captured[:path]
+  end
+
+  test "start_time_track sends no body and adopts ongoing on 409" do
+    client = HeyClient.new(@user)
+    posts = []
+    client.define_singleton_method(:request) do |method, path, body = nil, allow: []|
+      if method == :post
+        posts << { path: path, body: body, allow: allow }
+        client.instance_variable_set(:@last_status_code, 409)
+        return nil
+      end
+      { "id" => 321 }
+    end
+
+    result = client.start_time_track
+
+    assert_equal 1, posts.size
+    assert_equal "/calendar/ongoing_time_track.json", posts[0][:path]
+    assert_nil posts[0][:body]
+    assert_includes posts[0][:allow], 409
+    assert_equal 321, result["id"]
+  end
+
+  test "stop_time_track wraps ends_at under calendar_time_track" do
+    client = HeyClient.new(@user)
+    captured = nil
+    client.define_singleton_method(:request) do |method, path, body = nil, allow: []|
+      captured = { method: method, path: path, body: body }
+      {}
+    end
+
+    client.stop_time_track("44", category_title: "Focus work")
+
+    assert_equal :put, captured[:method]
+    assert_equal "/calendar/time_tracks/44.json", captured[:path]
+    assert_equal "Focus work", captured[:body].dig("calendar_time_track", :category_title)
+    assert captured[:body].dig("calendar_time_track", :ends_at).present?
+  end
+
+  test "email box methods use canonical laterbox asidebox trailbox paths" do
+    client = HeyClient.new(@user)
+    paths = []
+    client.define_singleton_method(:get) do |path, allow: []|
+      paths << path
+      { "postings" => [] }
+    end
+
+    client.reply_later
+    client.set_aside
+    client.paper_trail
+
+    assert_equal %w[/laterbox.json /asidebox.json /trailbox.json], paths
+  end
+
+  test "fetch_box follows Link rel=next when next_history_url is absent" do
+    client = HeyClient.new(@user)
+    paths = []
+    client.define_singleton_method(:get) do |path, allow: []|
+      paths << path
+      if path == "/laterbox.json"
+        client.instance_variable_set(:@last_link_header, '<https://app.hey.com/laterbox.json?page=abc>; rel="next"')
+        { "postings" => [ { "id" => 1, "kind" => "topic" } ] }
+      else
+        client.instance_variable_set(:@last_link_header, nil)
+        { "postings" => [ { "id" => 2, "kind" => "topic" } ] }
+      end
+    end
+
+    rows = client.reply_later
+    assert_equal 2, rows.size
+    assert_includes paths, "/laterbox.json"
+    assert_includes paths, "/laterbox.json?page=abc"
+  end
+
+  test "flatten_calendar_period expands occurrence_id into composite external id" do
+    client = HeyClient.new(@user)
+    raw = {
+      "kind" => "week",
+      "recordings" => {
+        "Calendar::Event" => [
+          {
+            "id" => 0,
+            "parent_id" => 88,
+            "occurrence_id" => "_",
+            "title" => "Weekly standup",
+            "starts_at" => "2026-04-15T15:00:00Z",
+            "ends_at" => "2026-04-15T15:30:00Z",
+            "calendar" => { "id" => 7 }
+          }
+        ]
+      }
+    }
+
+    rows = client.flatten_calendar_period(raw)
+    assert_equal 1, rows.size
+    assert_equal "88:2026-04-15", rows.first["id"]
+    assert_equal "7", rows.first["hey_calendar_id"]
+  end
+
+  test "calendar_week_events fetches /calendar/weeks/:date.json" do
+    client = HeyClient.new(@user)
+    paths = []
+    client.define_singleton_method(:get) do |path, allow: []|
+      paths << path
+      { "kind" => "week", "recordings" => { "Calendar::Event" => [] } }
+    end
+
+    client.calendar_week_events("2026-04-13")
+    assert_equal [ "/calendar/weeks/2026-04-13.json" ], paths
+  end
 end