Skip to content

spec(draft): add missing HostCapabilities fields (updateModelContext and message) #653

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
hydrosquall wants to merge 1 commit into
base: main
Choose a base branch
from
+31 −8
Open

spec(draft): add missing HostCapabilities fields (updateModelContext and message) #653

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 31 additions & 8 deletions specification/draft/apps.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -659,6 +659,22 @@ Example:
They describe the features and capabilities that the Host supports.

```typescript
/** Content block modalities that the host supports for a given capability. */
interface SupportedContentBlockModalities {
Copy link
Copy Markdown
Contributor Author

@hydrosquall hydrosquall May 6, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

See

ext-apps/src/spec.types.ts

Lines 462 to 475 in 0008d3b

export interface McpUiSupportedContentBlockModalities {
/** @description Host supports text content blocks. */
text?: {};
/** @description Host supports image content blocks. */
image?: {};
/** @description Host supports audio content blocks. */
audio?: {};
/** @description Host supports resource content blocks. */
resource?: {};
/** @description Host supports resource link content blocks. */
resourceLink?: {};
/** @description Host supports structured content. */
structuredContent?: {};
}

/** Host supports text content blocks. */
text?: {};
/** Host supports image content blocks. */
image?: {};
/** Host supports audio content blocks. */
audio?: {};
/** Host supports resource content blocks. */
resource?: {};
/** Host supports resource link content blocks. */
resourceLink?: {};
/** Host supports structured content. */
structuredContent?: {};
}

interface HostCapabilities {
/** Experimental features (structure TBD). */
experimental?: {};
Expand All @@ -678,14 +694,6 @@ interface HostCapabilities {
};
/** Host accepts log messages. */
logging?: {};
/**
* Host supports LLM sampling (sampling/createMessage) from the view.
* Mirrors MCP ClientCapabilities.sampling so hosts can pass it through.
*/
sampling?: {
/** Host supports tool use via `tools` and `toolChoice` params (SEP-1577). */
tools?: {};
};
/** Sandbox configuration applied by the host. */
sandbox?: {
/** Permissions granted by the host (camera, microphone, geolocation, clipboard-write). */
Expand All @@ -707,6 +715,21 @@ interface HostCapabilities {
baseUriDomains?: string[];
};
};
/**
* Host accepts context updates (ui/update-model-context) to be included in
Copy link
Copy Markdown
Contributor Author

@hydrosquall hydrosquall May 6, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Matches the ordering in the types

ext-apps/src/spec.types.ts

Lines 520 to 523 in 0008d3b

/** @description Host accepts context updates (ui/update-model-context) to be included in the model's context for future turns. */
updateModelContext?: McpUiSupportedContentBlockModalities;
/** @description Host supports receiving content messages (ui/message) from the view. */
message?: McpUiSupportedContentBlockModalities;

* the model's context for future turns.
*/
updateModelContext?: SupportedContentBlockModalities;
/** Host supports receiving content messages (ui/message) from the view. */
message?: SupportedContentBlockModalities;
/**
* Host supports LLM sampling (sampling/createMessage) from the view.
* Mirrors MCP ClientCapabilities.sampling so hosts can pass it through.
*/
sampling?: {
/** Host supports tool use via `tools` and `toolChoice` params (SEP-1577). */
tools?: {};
};
}
```

Expand Down
Loading