[Schema][Server] Add MCP Apps extension (io.modelcontextprotocol/ui) support#281
Open
chr-hertel wants to merge 1 commit into
Open
[Schema][Server] Add MCP Apps extension (io.modelcontextprotocol/ui) support#281chr-hertel wants to merge 1 commit into
chr-hertel wants to merge 1 commit into
Conversation
chr-hertel
force-pushed
the
feat/mcp-apps-extension
branch
from
9c9b41b to
d9ca7e6
Compare
chr-hertel
added
Server
chr-hertel
changed the title
chr-hertel
added
improves spec compliance
chr-hertel
force-pushed
the
feat/mcp-apps-extension
branch
from
d9ca7e6 to
ea82312
Compare
chr-hertel
force-pushed
the
feat/mcp-apps-extension
branch
8 times, most recently
from
1f1c1c6 to
f1a76a6
Compare
chr-hertel
changed the title
chr-hertel
force-pushed
the
feat/mcp-apps-extension
branch
from
f1a76a6 to
2039755
Compare
Adds support for the MCP Apps protocol extension, which lets servers expose interactive HTML UIs as resources rendered by spec-conforming clients (e.g. Goose) in sandboxed iframes. - Generic extension plumbing: ServerExtensionInterface and Builder::enableExtension(), with extensions advertised under capabilities.extensions during the initialize handshake. ClientCapabilities/ServerCapabilities gain an extensions field. - Schema DTOs under Mcp\Schema\Extension\Apps: the McpApps marker, UiToolMeta, ToolVisibility enum, UiResourceContentMeta, UiResourceCsp, and UiResourcePermissions (with empty-object presence markers per spec). - A worked weather example under examples/server/mcp-apps/ with a minimal spec-conforming view (ui/initialize handshake, postMessage JSONRPCMessage objects, and ResizeObserver-driven size reporting). - docs/extensions.md guide with pointers from index.md and examples.md to the ext-apps repository for the TypeScript SDK and richer view-side patterns. - Unit and inspector snapshot test coverage. Spec: https://github.com/modelcontextprotocol/ext-apps
chr-hertel
force-pushed
the
feat/mcp-apps-extension
branch
from
2039755 to
cf9ee8e
Compare
chr-hertel
requested review from
CodeWithKyrian,
Nyholm and
soyuka
as code owners
Member
Author
|
This could use some love as follow up when it comes to the Builder. maybe a |
chr-hertel
removed
the
needs more work
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Mcp\Schema\Extension\Apps\for the MCP Apps extension (io.modelcontextprotocol/ui, spec2026-01-26)extensionsfield to bothServerCapabilitiesandClientCapabilitiesfor extension negotiationToolVisibilityenum (model/app)examples/server/mcp-apps/demonstrating UI resources and tool-UI linkageDetails
The MCP Apps extension enables servers to expose interactive HTML UI applications as MCP resources. This PR adds server-side support:
McpApps(constants/helpers),UiResourceCsp,UiResourcePermissions,UiResourceContentMeta,UiToolMeta— all withfromArray()/jsonSerialize()andtoMetaArray()helpers for embedding in_metaextensionsparameter on both capability classes (backward-compatible, defaults tonull)resources/list,resources/read,tools/list,tools/callui/initialize,ui/open-link, etc.) which runs between the rendered HTML and the host applicationTest plan
make cs— coding standards passmake phpstan— static analysis passes (0 errors)make unit-tests— all 754 tests pass (34 new)npx @modelcontextprotocol/inspector php examples/server/mcp-apps/server.phpRunning in Goose
Screencast.from.2026-05-11.23-45-55.webm