Skip to content

feat: modality negotiation for ui/message and ui/update-model-context #119

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
idosal wants to merge 10 commits into
base: main
Choose a base branch
from
+492 −32
Open

feat: modality negotiation for ui/message and ui/update-model-context #119

Changes from 1 commit
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
ee557a4
fix: ui/message accepts message array
idosal Dec 10, 2025
20ea4d9
Merge remote-tracking branch 'origin/main' into fix/ui-message-content
idosal Jan 23, 2026
b31250f
modality negotiation
idosal Jan 23, 2026
e74ba3b
husky
idosal Jan 23, 2026
901f104
remove view-side validation
idosal Jan 23, 2026
90e9c24
husky
idosal Jan 23, 2026
34697f0
update lock
idosal Jan 23, 2026
94c432b
chore: update package-lock.json to sync with dependencies
idosal Jan 23, 2026
5bf54d2
merge from main
idosal Jan 23, 2026
50cf05e
Merge branch 'main' into fix/ui-message-content
ochafik Feb 12, 2026
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
10 changes: 6 additions & 4 deletions specification/draft/apps.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -506,10 +506,12 @@ Host SHOULD open the URL in the user's default browser or a new tab.
method: "ui/message",
params: {
role: "user",
content: {
type: "text",
text: string
}
content: [
{
type: "text",
text: string
}
]

Copilot AI Dec 10, 2025

Copy link

Choose a reason for hiding this comment

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

The specification should document what content types are supported in the content array. While the PR description mentions supporting images (e.g., "prompting the agent with a text message and an image"), the spec only shows a single text content block.

Consider adding:

  1. A reference to the MCP SDK's ContentBlock type definition
  2. Documentation of supported content types (text, image, etc.)
  3. An example showing multiple content items in the array (e.g., text + image)

This would help implementers understand the full capabilities of this API and align with the stated goal of supporting additional use cases like multi-modal messages.

Copilot uses AI. Check for mistakes.

@idosal idosal Dec 10, 2025

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

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

@ochafik I see that the SDK supports ContentBlock as-is. There are types that are extremely cool and open up really interesting use cases, but I'm not sure hosts would know how to support and may require negotiation (e.g., audio, embedded resource). Should we limit it to text (and perhaps image if we add negotiation) for now?

@ochafik ochafik Dec 11, 2025

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

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

@idosal let's just make it all negotiable:

export interface McpUiHostCapabilities {
  /* @description Optional support for ui/message and its content types */
  messages?: {
    text?: {};
    image?: {};
    audio?: {};
    resource?: {};
    resourceLink?: {};
  }
  ...
}

cc/ @antonpk1 fyi

@ochafik ochafik Dec 17, 2025

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

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

@idosal what do you think about that one?

@idosal idosal Jan 14, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

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

@ochafik sounds good. Let's merge this one and I'll open a new one for the negotiation

}
}

Expand Down
Loading