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Add ui/notifications/request-teardown notification for view-initiated termination (#215)

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* Add ui/close-resource request for UI to initiate termination

* Add missing METHOD export

* Fix typo in remaining ui/request-close

* Align spec terminology to teardown/termination instead of close/clearnup

* Implement final comments

* Removing view behavior on initiation of request termination
This commit is contained in:
Frédéric Barthelet 2026-03-19 21:01:59 +01:00 • committed by GitHub
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29
specification/draft/apps.mdx
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@ -1285,9 +1285,11 @@ Host MUST send this notification if the tool execution was cancelled, for any re
}
```
Host MUST send this notification before tearing down the UI resource, for any reason, including user action, resource re-allocation, etc. The Host MAY specify the reason.
Host MUST send this notification before tearing down the UI resource, for any reason, including user action, view-initiated teardown, resource re-allocation, etc. The Host MAY specify the reason.
Host SHOULD wait for a response before tearing down the resource (to prevent data loss).
#### Notifications (View → Host)
`ui/notifications/size-changed` - View's size changed
```typescript
@ -1303,6 +1305,22 @@ Host SHOULD wait for a response before tearing down the resource (to prevent dat
The View SHOULD send this notification when rendered content body size changes (e.g. using ResizeObserver API to report up to date size).
`ui/notifications/request-teardown` - View requests host to tear it down
```typescript
{
jsonrpc: "2.0",
method: "ui/notifications/request-teardown",
params: {}
}
```
The View MAY send this notification to request that the host tear it down. This enables View-initiated teardown flows (e.g., user clicks a "Done" button in the View).
**Host behavior:**
- Host MAY defer or ignore the teardown request.
- If the Host accepts the request, it MUST follow the graceful termination process by sending `ui/resource-teardown` to the View. The Host SHOULD wait for a response before tearing down the resource (to prevent data loss).
`ui/notifications/host-context-changed` - Host context has changed
```typescript
@ -1455,19 +1473,24 @@ sequenceDiagram
end
```
#### 4. Cleanup
#### 4. Teardown
The Host can tear down Views. Views may request teardown by sending `ui/notifications/request-teardown` to the Host. In any case, the Host MUST send `ui/resource-teardown` to allow the View to terminate gracefully.
```mermaid
sequenceDiagram
participant H as Host
participant UI as View (iframe)
opt View-initiated teardown
UI ->> H: ui/notifications/request-teardown
end
H ->> UI: ui/resource-teardown
UI --> UI: Graceful termination
UI -->> H: ui/resource-teardown response
H -x H: Tear down iframe and listeners
```
Note: Cleanup may be triggered at any point in the lifecycle following View initialization.
Note: Teardown may be triggered at any point in the lifecycle following View initialization.
#### Key Differences from Pre-SEP MCP-UI: