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refactor: use MCP resource types for ui/download-file params

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Replace custom {filename, content, mimeType, encoding} params with
standard MCP resource types: EmbeddedResource for inline content and
ResourceLink for host-resolved references.

New params shape:
  params: { contents: (EmbeddedResource | ResourceLink)[] }

This reuses existing MCP primitives instead of inventing new ones,
and enables hosts to show resource 'bubbles' or resolve ResourceLink
URIs via resources/read on the MCP server.
This commit is contained in:
Anton Pidkuiko MacBook 2026-02-20 12:00:35 +00:00
commit 3757271641
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1 changed files with 366 additions and 125 deletions
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59
src/generated/schema.ts generated
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@ -5,8 +5,10 @@ import { z } from "zod";
import {
ContentBlockSchema,
CallToolResultSchema,
EmbeddedResourceSchema,
ImplementationSchema,
RequestIdSchema,
ResourceLinkSchema,
ToolSchema,
} from "@modelcontextprotocol/sdk/types.js";
@ -161,41 +163,6 @@ export const McpUiOpenLinkResultSchema = z
})
.passthrough();
/**
* @description Request to download a file through the host.
*
* Sent from the View to the Host when the app wants to trigger a file download.
* Since MCP Apps run in sandboxed iframes where direct downloads are blocked,
* this provides a host-mediated mechanism for file exports.
* The host SHOULD show a confirmation dialog before initiating the download.
*
* @see {@link app!App.downloadFile `App.downloadFile`} for the method that sends this request
*/
export const McpUiDownloadFileRequestSchema = z.object({
method: z.literal("ui/download-file"),
params: z.object({
/** @description Suggested filename for the download. */
filename: z.string().describe("Suggested filename for the download."),
/** @description File content — text or base64-encoded binary. */
content: z
.string()
.describe("File content \u2014 text or base64-encoded binary."),
/** @description MIME type of the file (e.g. "image/svg+xml", "application/json"). */
mimeType: z
.string()
.describe(
'MIME type of the file (e.g. "image/svg+xml", "application/json").',
),
/** @description Content encoding. Defaults to "utf-8". Use "base64" for binary content. */
encoding: z
.union([z.literal("utf-8"), z.literal("base64")])
.optional()
.describe(
'Content encoding. Defaults to "utf-8". Use "base64" for binary content.',
),
}),
});
/**
* @description Result from a file download request.
* @see {@link McpUiDownloadFileRequest `McpUiDownloadFileRequest`}
@ -755,6 +722,28 @@ export const McpUiClientCapabilitiesSchema = z.object({
),
});
/**
* @description Request to download a file through the host.
*
* Sent from the View to the Host when the app wants to trigger a file download.
* Since MCP Apps run in sandboxed iframes where direct downloads are blocked,
* this provides a host-mediated mechanism for file exports.
* The host SHOULD show a confirmation dialog before initiating the download.
*
* @see {@link app!App.downloadFile `App.downloadFile`} for the method that sends this request
*/
export const McpUiDownloadFileRequestSchema = z.object({
method: z.literal("ui/download-file"),
params: z.object({
/** @description Resource contents to download — embedded (inline data) or linked (host fetches). Uses standard MCP resource types. */
contents: z
.array(z.union([EmbeddedResourceSchema, ResourceLinkSchema]))
.describe(
"Resource contents to download \u2014 embedded (inline data) or linked (host fetches). Uses standard MCP resource types.",
),
}),
});
/**
* @description Request to send a message to the host's chat interface.
* @see {@link app!App.sendMessage `App.sendMessage`} for the method that sends this request