diff --git a/.changeset/modal-actions-are-client-only.md b/.changeset/modal-actions-are-client-only.md
new file mode 100644
index 0000000000..946a5bbd4e
--- /dev/null
+++ b/.changeset/modal-actions-are-client-only.md
@@ -0,0 +1,21 @@
+---
+'@objectstack/example-todo': patch
+---
+
+**[#3959] `app-todo`'s `defer_task` / `set_reminder` are `type: 'script'`, not `type: 'modal'`.**
+
+Both declared `type: 'modal'` with a `target` naming a modal page that does not
+exist (`defer_task_modal`, `set_reminder_modal`), while their handlers sat
+registered under `deferTask` / `setReminder` — keys no declaration could
+address. A `modal` action has no server dispatch (`headlessActionTypeError`
+rejects it over REST), so neither handler had ever executed: the example
+shipped business logic that could not run, and ADR-0110 D5's boot inventory
+flagged both on its first pass.
+
+Both already declared the `params` their handlers read, so they were always
+"collect input, then run server-side" actions — which is `type: 'script'` with
+`params`. The runner collects the same dialog and the handler now actually runs.
+
+The action-type table in `content/docs/ui/actions.mdx` said `modal` meant
+"collect input, then submit to a handler", contradicting the same page's own
+REST table (`modal` → 400, nothing for the server to run). Corrected.
diff --git a/content/docs/ui/actions.mdx b/content/docs/ui/actions.mdx
index 15f01f59a5..c33cb25380 100644
--- a/content/docs/ui/actions.mdx
+++ b/content/docs/ui/actions.mdx
@@ -19,7 +19,7 @@ The types you'll actually use:
 | `script` *(default)* | Run server-side logic | Inline `body` **or** a handler registered via `target` |
 | `flow` | Launch a flow (e.g. a screen-flow wizard) | `target` names the flow |
 | `url` | Navigate / open a link | `target` is the URL (`${ctx.record.id}` interpolation supported) |
-| `modal` | Open a modal page to collect input, then submit to a handler | `target` names the modal page |
+| `modal` | Open a modal page — client-side only, no server dispatch | `target` names the modal page (to collect input *and* run logic, use `script` + `params`) |
 | `api` | Call an HTTP endpoint directly | `target` is the endpoint; `method` / `bodyShape` / `bodyExtra` shape the request |
 | `form` | Open a form view, prefilled with the current record | `target` names the FormView; routed to `/forms/:target?recordId=…` |
 
diff --git a/examples/app-todo/src/actions/task.actions.ts b/examples/app-todo/src/actions/task.actions.ts
index 2956f69bcf..0303797eda 100644
--- a/examples/app-todo/src/actions/task.actions.ts
+++ b/examples/app-todo/src/actions/task.actions.ts
@@ -36,14 +36,25 @@ export const StartTaskAction = defineAction({
   },
 });
 
-/** Defer Task */
+/**
+ * Defer Task — collect input, then run server-side.
+ *
+ * [ADR-0110] This is `type: 'script'` with `params`, NOT `type: 'modal'`. A
+ * `modal` action's `target` names a page to OPEN and has no server dispatch
+ * (`headlessActionTypeError` rejects it), so the old
+ * `type: 'modal', target: 'defer_task_modal'` pointed at a page that does not
+ * exist while `deferTask` sat registered under a key no declaration could
+ * address — business logic that had never once executed (#3959). `script` +
+ * `params` is the supported shape: the runner collects the same dialog, then
+ * the handler runs with those values.
+ */
 export const DeferTaskAction = defineAction({
   name: 'defer_task',
   label: 'Defer Task',
   objectName: 'todo_task',
   icon: 'clock',
-  type: 'modal',
-  target: 'defer_task_modal',
+  type: 'script',
+  target: 'deferTask',
   locations: ['record_header'],
   params: [
     {
@@ -63,14 +74,14 @@ export const DeferTaskAction = defineAction({
   refreshAfter: true,
 });
 
-/** Set Reminder */
+/** Set Reminder — collect input, then run server-side (see DeferTaskAction). */
 export const SetReminderAction = defineAction({
   name: 'set_reminder',
   label: 'Set Reminder',
   objectName: 'todo_task',
   icon: 'bell',
-  type: 'modal',
-  target: 'set_reminder_modal',
+  type: 'script',
+  target: 'setReminder',
   locations: ['record_header', 'list_item'],
   params: [
     {
diff --git a/examples/app-todo/src/actions/task.handlers.ts b/examples/app-todo/src/actions/task.handlers.ts
index 2baffe585d..714d36a48e 100644
--- a/examples/app-todo/src/actions/task.handlers.ts
+++ b/examples/app-todo/src/actions/task.handlers.ts
@@ -82,7 +82,7 @@ export async function deleteCompletedTasks(ctx: ActionContext): Promise<void> {
   }
 }
 
-/** Defer a task by updating its due date (modal form submission handler) */
+/** Defer a task by updating its due date (params collected by the action dialog) */
 export async function deferTask(ctx: ActionContext): Promise<void> {
   const { record, engine, params } = ctx;
   await engine.update('todo_task', record.id as string, {
@@ -92,7 +92,7 @@ export async function deferTask(ctx: ActionContext): Promise<void> {
   });
 }
 
-/** Set a reminder on a task (modal form submission handler) */
+/** Set a reminder on a task (params collected by the action dialog) */
 export async function setReminder(ctx: ActionContext): Promise<void> {
   const { record, engine, params } = ctx;
   await engine.update('todo_task', record.id as string, {