[2026-07-28] Extensions framework + Tasks + MCP Apps

Open

#335 opened on May 26, 2026 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty: 5/5
Estimated time: Over a week
Newbie friendliness: 28/100

Issue type: Feature
Clarity: Mostly clear
Activity status: Quiet
Tech stack: php
Domain: backend-api-design

Research direction

Start with sub-issue #344 and SEP-2133, since the Extensions framework blocks the Tasks and MCP Apps work. Then review sub-issues #345–#352 and their linked SEPs; the milestone is done when the foundation, Tasks, and MCP Apps items are implemented in dependency order.

Written by the indexing model from the issue text.

Description

2026-07-28 Client enhancement improves spec compliance needs design Schema Server

Tracking issue for the MCP Spec 2026-07-28 release — Extensions framework + Tasks + MCP Apps milestone.

SEP-2133 establishes the extension mechanism (capability negotiation + extensible handler dispatch). Both SEP-2663 (Tasks) and SEP-1865 (MCP Apps) graduate to extensions on top of it. Land SEP-2133 first; Tasks and Apps depend on it.

SEPs covered

SEP	Title	Spec PR
SEP-2133	Extensions framework for MCP	#2133
SEP-2663	Tasks Extension	#2663
SEP-1865	MCP Apps — Interactive User Interfaces	#1865

Sub-issues

Foundation (blocker for Tasks and Apps):

#344 — SEP-2133: Extensions framework (capability negotiation + ExtensionRegistry + extensible dispatch)

SEP-2663 Tasks:

#345 — Schema: Task shape, resultType discriminator, tasks/* request/result types
#346 — Server: TasksExtension, capability gate, tasks/get/update/cancel handlers
#347 — Server: TaskStoreInterface with InMemory and PSR-16 stores
#348 — Server: Handlers return task handles; the application advances the task
#349 — Client: Poll task handles and answer inputRequests via tasks/update

SEP-1865 MCP Apps:

#350 — Schema: Content types, ui:// scheme, tool metadata fields
#351 — Server: ext-apps registration, builder API, #[McpUiResource] attribute
#352 — Server/Examples: Link tools to UI templates + example server + inspector tests

Notes

All three SEPs are merged into the spec repo.
SEP-2663 supersedes SEP-1686. Issue #139 (SEP-1686 Tasks) was closed and rescoped to this milestone — the SEP-1686 design was never shipped by the PHP SDK, so there is nothing to deprecate.
SEP-1865 spec lives at modelcontextprotocol/ext-apps.

Dominant language: PHP
Stars: 1.6k
Forks: 173
Avg merge: 2d 49m
Merged PRs (30d): 23

Contributor guide

Open the contributing guide

First steps

Read the whole issue, then the project's contributing guide.
Comment on the issue to say you are picking it up — it saves two people doing the same work.
Fork the repository and make your change on a branch.
Open a pull request that references the issue number.

Similar issues

PHP warning in document.php after importing a saved header template in Elementor 4.3.0 Open

status/awaiting_triage

Difficulty 2/5 1-3 hours Newbie friendliness 75/100

elementor/elementor#37396 · Opened Sep 23, 2026
Recognize Blue Oak Model License 1.0.0 as GPL-compatible Open

Difficulty 1/5 Under an hour Newbie friendliness 90/100

WordPress/plugin-check#1486 · Opened Sep 23, 2026
Support the back-to-top button on Drupal Canvas page variants Open

enhancement

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

az-digital/az_quickstart#6019 · Opened Sep 23, 2026
[Feature]: ABM adapter: validate the private key when settings are saved Open

Difficulty 2/5 1-3 hours Newbie friendliness 75/100

grokability/snipe-it#19688 · Opened Sep 23, 2026
Admin assets are being enqueued on front end Open

Difficulty 2/5 1-3 hours Newbie friendliness 85/100

alleyinteractive/archiveless#88 · Opened Sep 22, 2026

More PHP issues