chore(deps): bump astral-sh/setup-uv from 10.0.1 to 10.1.0 (#512)

Bumps [astral-sh/setup-uv](https://github.com/astral-sh/setup-uv) from 10.0.1 to 10.1.0.
- [Release notes](https://github.com/astral-sh/setup-uv/releases)
- [Commits](https://github.com/astral-sh/setup-uv/compare/v10.0.1...v10.1.0)

---
updated-dependencies:
- dependency-name: astral-sh/setup-uv
  dependency-version: 10.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.gitattributes

@@ -1,7 +1,12 @@
-/.git* export-ignore
+/.github export-ignore
+/.phpdoc export-ignore
+/docs export-ignore
 /examples export-ignore
 /tests export-ignore
 /.php-cs-fixer.dist.php export-ignore
+/Makefile export-ignore
+/mkdocs.yml export-ignore
+/requirements-docs.txt export-ignore
+/phpdoc.dist.xml
 /phpstan* export-ignore
 /phpunit.xml.dist export-ignore
-/Makefile export-ignore

.github/CODEOWNERS

@@ -1 +1 @@
-* @chr-hertel @Nyholm @CodeWithKyrian
+* @chr-hertel @Nyholm @CodeWithKyrian @soyuka

.github/dependabot.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+  - package-ecosystem: composer
+    directory: /
+    schedule:
+      interval: weekly
+
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/conformance-weekly.yaml

@@ -0,0 +1,189 @@
+name: conformance-weekly
+
+# Tracks the newest published @modelcontextprotocol/conformance; the
+# on:pull_request pipeline pins an exact version instead. Also publishes
+# score badges to the orphan `badges` branch, consumed by the README.
+on:
+  schedule:
+    - cron: '0 6 * * 1' # Mondays 06:00 UTC
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  issues: write
+
+jobs:
+  server:
+    name: conformance / server (${{ matrix.spec-version }}, ${{ matrix.dist-tag }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - spec-version: '2025-11-25'
+            dist-tag: latest
+            path: '/'
+            baseline: conformance-baseline-2025-11-25.yml
+          - spec-version: '2026-07-28'
+            dist-tag: alpha
+            path: '/'
+            baseline: conformance-baseline-2026-07-28.yml
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v7
+        with:
+          node-version: '22'
+      - run: composer install --prefer-dist --no-progress --no-interaction
+      - name: Start conformance server
+        run: |
+          mkdir -p tests/Conformance/sessions tests/Conformance/logs
+          chmod -R 777 tests/Conformance/sessions tests/Conformance/logs
+          docker compose -f tests/Conformance/Fixtures/docker-compose.yml up -d
+          sleep 5
+      - name: Run conformance tests
+        working-directory: ./tests/Conformance
+        run: >-
+          npx --yes @modelcontextprotocol/conformance@${{ matrix.dist-tag }} server
+          --url http://localhost:8000${{ matrix.path }}
+          --suite all
+          --spec-version ${{ matrix.spec-version }}
+          --expected-failures ${{ matrix.baseline }}
+          --output-dir results
+      - name: Generate score badge
+        if: always()
+        run: php tests/Conformance/score.php server ${{ matrix.spec-version }}
+      - name: Show docker logs on failure
+        if: failure()
+        run: docker compose -f tests/Conformance/Fixtures/docker-compose.yml logs
+      - name: Upload conformance results
+        if: failure()
+        uses: actions/upload-artifact@v7
+        with:
+          name: conformance-server-results-${{ matrix.spec-version }}
+          path: |
+            tests/Conformance/logs
+            tests/Conformance/results
+      - name: Upload score badge
+        if: always()
+        uses: actions/upload-artifact@v7
+        with:
+          name: badge-server-${{ matrix.spec-version }}
+          path: tests/Conformance/server-conformance-${{ matrix.spec-version }}.json
+
+  client:
+    name: conformance / client (${{ matrix.spec-version }}, ${{ matrix.dist-tag }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - spec-version: '2025-11-25'
+            dist-tag: latest
+            baseline: conformance-baseline-2025-11-25.yml
+          - spec-version: '2026-07-28'
+            dist-tag: alpha
+            baseline: conformance-baseline-2026-07-28.yml
+    steps:
+      - uses: actions/checkout@v7
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.4'
+          coverage: none
+      - uses: actions/setup-node@v7
+        with:
+          node-version: '22'
+      - run: composer install --prefer-dist --no-progress --no-interaction
+      - run: mkdir -p tests/Conformance/logs
+      - name: Run conformance tests
+        working-directory: ./tests/Conformance
+        run: >-
+          npx --yes @modelcontextprotocol/conformance@${{ matrix.dist-tag }} client
+          --command "php ${{ github.workspace }}/tests/Conformance/client.php"
+          --suite all
+          --spec-version ${{ matrix.spec-version }}
+          --expected-failures ${{ matrix.baseline }}
+          --output-dir results
+      - name: Generate score badge
+        if: always()
+        run: php tests/Conformance/score.php client ${{ matrix.spec-version }}
+      - name: Upload conformance results
+        if: failure()
+        uses: actions/upload-artifact@v7
+        with:
+          name: conformance-client-results-${{ matrix.spec-version }}
+          path: |
+            tests/Conformance/logs
+            tests/Conformance/results
+      - name: Upload score badge
+        if: always()
+        uses: actions/upload-artifact@v7
+        with:
+          name: badge-client-${{ matrix.spec-version }}
+          path: tests/Conformance/client-conformance-${{ matrix.spec-version }}.json
+
+  notify:
+    name: Open issue on failure
+    runs-on: ubuntu-latest
+    needs: [server, client]
+    if: failure()
+    env:
+      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      GH_REPO: ${{ github.repository }}
+      EVENT_NAME: ${{ github.event_name }}
+      RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
+    steps:
+      - name: File or comment tracking issue
+        run: |
+          existing=$(gh issue list --label conformance-weekly --state open --json number --jq '.[0].number // empty')
+          if [ -n "$existing" ]; then
+            gh issue comment "$existing" --body "New failure on $(date -u +%FT%TZ): $RUN_URL"
+          else
+            gh issue create \
+              --title '[conformance] Weekly conformance run failed' \
+              --label conformance-weekly \
+              --body "Conformance against the newest published \`@modelcontextprotocol/conformance\` failed.
+
+          - Run: $RUN_URL
+          - Trigger: $EVENT_NAME
+          - Date: $(date -u +%FT%TZ)
+
+          Upstream likely published a release whose scenarios the SDK does not satisfy. Either fix the SDK, update the conformance fixtures, or add the new failure to the matching \`tests/Conformance/conformance-baseline-<spec-version>.yml\`."
+          fi
+
+  publish:
+    name: Publish conformance badges
+    runs-on: ubuntu-latest
+    needs: [server, client]
+    if: ${{ !cancelled() && github.repository == 'modelcontextprotocol/php-sdk' }}
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/download-artifact@v8
+        with:
+          pattern: badge-*
+          path: badges-in
+          merge-multiple: true
+      - name: Publish to badges branch
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+          if git ls-remote --exit-code --heads origin badges >/dev/null 2>&1; then
+            git fetch origin badges
+            git worktree add badges-wt badges
+          else
+            git worktree add --detach badges-wt
+            git -C badges-wt checkout --orphan badges
+            git -C badges-wt rm -rf --quiet . >/dev/null 2>&1 || true
+          fi
+
+          rm -f badges-wt/server-conformance.json badges-wt/client-conformance.json
+          cp badges-in/*.json badges-wt/
+
+          cd badges-wt
+          git add -A
+          if git diff --cached --quiet; then
+            echo "Conformance scores unchanged."
+          else
+            git commit -m "Update conformance score badges"
+            git push origin badges
+          fi

.github/workflows/docs.yml

@@ -0,0 +1,63 @@
+name: Documentation
+
+# The site is built by `make docs`: Zensical renders the guides under docs/
+# (see mkdocs.yml) and phpDocumentor renders the API reference into /api/.
+# Pull requests build only — the build is strict, so a broken internal link
+# fails CI instead of shipping a dead link to the site.
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: docs-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.4'
+          coverage: "none"
+
+      - name: Install Composer dependencies
+        uses: "ramsey/composer-install@v4"
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v10.1.0
+        with:
+          enable-cache: true
+
+      - name: Build documentation
+        run: make docs
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@v5
+        with:
+          path: ./site
+
+  deploy:
+    needs: build
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v5

.github/workflows/pipeline.yaml

@@ -5,6 +5,10 @@ permissions:
   contents: read
   pull-requests: write
 
+env:
+  # Pinned exact version; conformance-weekly.yaml tracks upstream releases.
+  CONFORMANCE_PKG: "@modelcontextprotocol/conformance@0.2.0-alpha.11"
+
 jobs:
   unit:
     runs-on: ubuntu-latest
@@ -23,13 +27,16 @@ jobs:
           - symfony-version: '7.4.*'
             dependencies: 'highest'
             php: '8.4'
+          - symfony-version: '8.0.*'
+            dependencies: 'highest'
+            php: '8.4'
 
     env:
       SYMFONY_REQUIRE: ${{ matrix.symfony-version || '>=6.4' }}
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v7
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -39,18 +46,40 @@ jobs:
           coverage: "none"
 
       - name: Install Composer
-        uses: "ramsey/composer-install@v3"
+        uses: "ramsey/composer-install@v4"
         with:
           dependency-versions: "${{ matrix.dependencies }}"
 
       - name: Tests
         run: vendor/bin/phpunit --testsuite=unit
 
+  integration:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php: ['8.1', '8.2', '8.3', '8.4', '8.5']
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: "none"
+
+      - name: Install Composer
+        uses: "ramsey/composer-install@v4"
+
+      - name: Tests
+        run: vendor/bin/phpunit --testsuite=integration
+
   inspector:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v7
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -59,21 +88,143 @@ jobs:
           coverage: "none"
 
       - name: Setup Node
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v7
         with:
           node-version: '22'
 
       - name: Install Composer
-        uses: "ramsey/composer-install@v3"
+        uses: "ramsey/composer-install@v4"
 
       - name: Tests
         run: vendor/bin/phpunit --testsuite=inspector
 
+  conformance-server:
+    name: conformance / server (${{ matrix.spec-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - spec-version: '2025-11-25'
+            path: '/'
+            baseline: conformance-baseline-2025-11-25.yml
+          - spec-version: '2026-07-28'
+            path: '/'
+            baseline: conformance-baseline-2026-07-28.yml
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Setup Node
+        uses: actions/setup-node@v7
+        with:
+          node-version: '22'
+
+      - name: Install Composer
+        uses: "ramsey/composer-install@v4"
+
+      - name: Start conformance server
+        run: |
+          mkdir -p tests/Conformance/sessions tests/Conformance/logs
+          chmod -R 777 tests/Conformance/sessions tests/Conformance/logs
+          docker compose -f tests/Conformance/Fixtures/docker-compose.yml up -d
+          sleep 5
+
+      - name: Run conformance tests
+        working-directory: ./tests/Conformance
+        run: >-
+          npx --yes ${{ env.CONFORMANCE_PKG }} server
+          --url http://localhost:8000${{ matrix.path }}
+          --suite all
+          --spec-version ${{ matrix.spec-version }}
+          --expected-failures ${{ matrix.baseline }}
+
+      - name: Show logs on failure
+        if: failure()
+        run: |
+          echo "=== Docker Compose Logs ==="
+          docker compose -f tests/Conformance/Fixtures/docker-compose.yml logs
+          echo ""
+          echo "=== Conformance Log ==="
+          cat tests/Conformance/logs/conformance.log 2>/dev/null || echo "No conformance log found"
+          echo ""
+          echo "=== Test Results (first failed test) ==="
+          find tests/Conformance/results -name "checks.json" 2>/dev/null | head -3 | while read f; do
+            echo "--- $f ---"
+            cat "$f"
+            echo ""
+          done || echo "No results found"
+          echo ""
+          echo "=== Directory permissions ==="
+          ls -la tests/Conformance/
+          ls -la tests/Conformance/logs/ 2>/dev/null || echo "logs dir issue"
+          ls -la tests/Conformance/sessions/ 2>/dev/null || echo "sessions dir issue"
+
+      - name: Cleanup
+        if: always()
+        run: docker compose -f tests/Conformance/Fixtures/docker-compose.yml down
+
+  conformance-client:
+    name: conformance / client (${{ matrix.spec-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - spec-version: '2025-11-25'
+            baseline: conformance-baseline-2025-11-25.yml
+          - spec-version: '2026-07-28'
+            baseline: conformance-baseline-2026-07-28.yml
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.4'
+          coverage: "none"
+
+      - name: Setup Node
+        uses: actions/setup-node@v7
+        with:
+          node-version: '22'
+
+      - name: Install Composer
+        uses: "ramsey/composer-install@v4"
+
+      - name: Create log directory
+        run: mkdir -p tests/Conformance/logs
+
+      - name: Run client conformance tests
+        working-directory: ./tests/Conformance
+        run: >-
+          npx --yes ${{ env.CONFORMANCE_PKG }} client
+          --command "php ${{ github.workspace }}/tests/Conformance/client.php"
+          --suite all
+          --spec-version ${{ matrix.spec-version }}
+          --expected-failures ${{ matrix.baseline }}
+
+      - name: Show logs on failure
+        if: failure()
+        run: |
+          echo "=== Client Conformance Log ==="
+          cat tests/Conformance/logs/client-conformance.log 2>/dev/null || echo "No client conformance log found"
+          echo ""
+          echo "=== Test Results ==="
+          find tests/Conformance/results -name "checks.json" 2>/dev/null | head -3 | while read f; do
+            echo "--- $f ---"
+            cat "$f"
+            echo ""
+          done || echo "No results found"
+
   qa:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v7
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -85,10 +236,15 @@ jobs:
         run: composer validate --strict
 
       - name: Install Composer
-        uses: "ramsey/composer-install@v3"
+        uses: "ramsey/composer-install@v4"
 
       - name: Code Style PHP
         run: vendor/bin/php-cs-fixer fix --dry-run
 
       - name: PHPStan
         run: vendor/bin/phpstan analyse
+
+      # Only the phpDocumentor half: this job is PHP-only, and the Zensical
+      # guides are built (strictly) by the Documentation workflow.
+      - name: Documentation
+        run: make docs-api

.gitignore

@@ -6,3 +6,16 @@ vendor
 examples/**/dev.log
 examples/**/cache
 examples/**/sessions
+tests/Conformance/client-conformance.json
+tests/Conformance/server-conformance.json
+tests/Conformance/results*
+tests/Conformance/sessions
+tests/Conformance/logs/*.log
+
+# phpDocumentor
+.phpdoc/build/
+.phpdoc/cache/
+
+# Documentation site (make docs)
+/site/
+/.cache/

.php-cs-fixer.dist.php

@@ -31,8 +31,6 @@ return (new Config())
     ->setRules([
         '@Symfony' => true,
         '@Symfony:risky' => true,
-        'protected_to_private' => false,
-        'declare_strict_types' => false,
         'header_comment' => ['header' => $fileHeader],
         'php_unit_test_case_static_method_calls' => ['call_type' => 'this'],
     ])

.phpdoc/template/base.html.twig

@@ -0,0 +1,13 @@
+{% extends 'layout.html.twig' %}
+
+{% set topMenu = {
+    "menu": [
+        { "name": "Guides", "url": "/"},
+        { "name": "Specification", "url": "https://modelcontextprotocol.io/" }
+    ],
+    "social": [
+        { "iconClass": "fab fa-github", "url": "https://github.com/modelcontextprotocol/php-sdk"},
+        { "iconClass": "fab fa-discord", "url": "https://discord.gg/6CSzBmMkjX"}
+    ]
+}
+%}

.phpdoc/template/components/header-title.html.twig

@@ -0,0 +1,10 @@
+<h1 class="phpdocumentor-title">
+    <a href="/" class="phpdocumentor-title__link">
+        <svg xmlns="http://www.w3.org/2000/svg" width="40" height="40" viewBox="0 0 195 195" fill="none">
+            <path d="M25 97.8528L92.8823 29.9706C102.255 20.598 117.451 20.598 126.823 29.9706V29.9706C136.196 39.3431 136.196 54.5391 126.823 63.9117L75.5581 115.177" stroke="black" stroke-width="12" stroke-linecap="round"/>
+            <path d="M76.2653 114.47L126.823 63.9117C136.196 54.5391 151.392 54.5391 160.765 63.9117L161.118 64.2652C170.491 73.6378 170.491 88.8338 161.118 98.2063L99.7248 159.6C96.6006 162.724 96.6006 167.789 99.7248 170.913L112.331 183.52" stroke="black" stroke-width="12" stroke-linecap="round"/>
+            <path d="M109.853 46.9411L59.6482 97.1457C50.2757 106.518 50.2757 121.714 59.6482 131.087V131.087C69.0208 140.459 84.2168 140.459 93.5894 131.087L143.794 80.8822" stroke="black" stroke-width="12" stroke-linecap="round"/>
+        </svg>
+        <span style="margin-left: 0.25em;">{{ project.name }}</span>
+    </a>
+</h1>

CHANGELOG.md

@@ -2,6 +2,128 @@
 
 All notable changes to `mcp/sdk` will be documented in this file.
 
+0.9.0
+-----
+
+* [BC Break] Remove the `providerClass` argument of `#[CompletionProvider]`. Use `provider:`, which takes the same class-string and is now the first positional argument.
+* Add `HttpTransport::getSessionId()` to read the server-minted `Mcp-Session-Id`: a request-scoped caller can persist it and pass it back through the constructor's `$headers` on a later transport. Always `null` on `2026-07-28`, which removed protocol-level sessions.
+* Fix OIDC discovery rejecting issuers with a trailing slash (e.g. Authentik, Auth0).
+
+0.8.0
+-----
+
+* Support for MCP spec version 2026-07-28 incl. stateless HTTP transport
+  * Negotiate the protocol revision during `initialize`: the server counter-offers a revision it supports and the client fails the handshake instead of continuing on an unagreed one. Adds `Client::getProtocolVersion()`.
+  * Serve both protocol eras from one endpoint: `StreamableHttpTransport` classifies each request (`InboundClassifier`) and routes it to the matching dispatcher, so one URL answers modern and handshake-era clients alike. `Builder::withoutModernEra()` opts out, `Builder::setModernVersions()` narrows the modern leg.
+  * Speak the lifecycle from the client: `Client` opens with `server/discover`, stamps `_meta` with version, capabilities and client info, and sends the `Mcp-Method`/`Mcp-Name`/`Mcp-Param-*` headers (via `Client\Stateless\ToolCatalog`). `Schema\Wire\McpHeader` holds the shared header names.
+  * Add multi round-trip requests (SEP-2322): a handler returning `InputRequiredResult` yields `resultType: "input_required"` with an opaque, signed `requestState` (`RequestStateCodec`, key via `Builder::setRequestState()`); the client retries with `inputResponses`, read through `RequestContext::getInputContext()` and its typed `elicitResult()`/`samplingResult()`/`rootsResult()`. On the client, `InputRequestResolver` answers such results automatically from the host's elicitation, sampling and roots handlers.
+  * Serve `ClientGateway::elicit()`/`elicitUrl()` on every revision: where the client cannot be asked mid-request, `Server\Stateless\ElicitationReplay` turns the ask into `input_required` and resumes once re-sent — the handler is entered once per ask. `InputRequiredShim` does the reverse for handshake-era clients. `sample()`/`listRoots()` raise a `LogicException` on `2026-07-28`, which removed them.
+  * Run stateless handlers in a fiber so `$gateway->progress()`/`log()` stream over SSE when the handler emits something and the client accepts `text/event-stream`; honour `io.modelcontextprotocol/logLevel` (SEP-2575). Adds `LoggingLevel::severity()`/`isAtLeast()`.
+  * Deliver notifications on `subscriptions/listen` (SEP-2575) via `NotificationBusInterface` — `InMemoryNotificationBus` for persistent runtimes, `Psr16NotificationBus` for PHP-FPM — set with `Builder::setNotificationBus()`; `Builder::setSubscriptionLifetime()` replaces the hard-coded 30s ceiling.
+  * Validate the standard request headers (SEP-2243) with `StandardHeaderValidator` (`Builder::setHeaderValidator()`), answering `-32020` when they contradict the body.
+  * Add `Wire\CachePolicy` (`Builder::setCachePolicy()`) for SEP-2549 caching hints; defaults to `ttlMs: 0, cacheScope: private`. A `ReadResourceResult` may override with its own values.
+  * Carry W3C trace context (SEP-414): `traceparent`/`tracestate`/`baggage` from `_meta` are exposed via `RequestContext::getTraceContext()` and echoed onto the request's notifications.
+  * Close the schema gaps for `2025-06-18`/`2025-11-25` and add the `2026-07-28` surface (SEP-2106): url-mode elicitation (`ClientGateway::elicitUrl()`/`supportsElicitationUrl()`), `Implementation::title`, and `outputSchema`/`structuredContent` accepting any JSON value.
+  * Deprecate Roots, Sampling and Logging (SEP-2577, earliest removal `2027-07-28`); they keep working but trigger a deprecation notice.
+  * [BC Break] Answer a not-found subject with `-32602` instead of `-32002` (SEP-2164): `resources/read` picks the code by revision (`-32602` from `2026-07-28` on), `prompts/get`, `completion/complete` and `tools/call` switch on every revision. Adds `ProtocolVersion::usesInvalidParamsForResourceNotFound()`.
+  * [BC Break] A list-shaped tool result is only sent as `structuredContent` on `2026-07-28`+; older revisions keep the JSON-encoded value in `content`.
+* [BC Break] Add the extensions framework (SEP-2133) MCP Apps sits on: `ExtensionInterface::getId()` returns an `ExtensionIdentifier` value object, and the interface gains `getMessages()`/`getRequestHandlers()` (extend `AbstractExtension` to skip both). `MessageFactory::make()` takes an `$additional` message list; `RequestHandlerInterface`'s result template is covariant. `ServerExtensionInterface` is replaced by the side-agnostic `Schema\Extension\ExtensionInterface`.
+* Add client-side extension negotiation: `ClientGateway::supportsExtension()`, `Client\Builder::enableExtension()`, `ClientCapabilities::withExtensions()`.
+* Add sampling-with-tools: sampling requests can carry tools and tool-choice preferences, messages support tool-use/tool-result blocks, and clients advertise `sampling.context`/`sampling.tools` (`ClientGateway::supportsSamplingTools()`/`supportsSamplingContext()`). Requests violating the tool-flow rules are rejected with a JSON-RPC error.
+* [BC Break] `SamplingMessage::$content` and `CreateSamplingMessageResult::$content` may be a list of content blocks — use `getContentBlocks()`. `CreateSamplingMessageResult` rejects roles other than `assistant` and empty content.
+* Add client-side Roots support (`RootsCallbackInterface`, `Client::sendRootsListChanged()`) and server-side `ClientGateway::listRoots()`/`supportsRoots()`/`supportsSampling()`.
+* Add `Schema\Content\ResourceLink` to reference a resource by URI in tool results and prompt messages.
+* [BC Break] `Schema\JsonRpc\Error` accepts `null` as `$id`; an unreadable id now omits the member instead of sending `"id": ""`. `MessageFactory` decodes a missing or null id as an id-less error.
+* Preserve the request `id` on an invalid-but-parseable message (`-32600`) via `InvalidInputMessageException::getRequestId()`.
+* [BC Break] Drop the SDK-only name pattern on `ResourceDefinition`/`ResourceTemplate` `$name`; the spec allows any string.
+* Log expected tool failures (`ToolCallException`) at debug level instead of error.
+* Add `annotations` to `ImageContent`.
+* Fix empty tool/resource schemas serializing as `[]` instead of `{}`.
+* Fix `PromptResultFormatter` dropping `annotations`, `_meta` and `mimeType` for plain-array content.
+
+0.7.0
+-----
+
+* Add client-side elicitation support: `ElicitationCallbackInterface`, `ElicitationRequestHandler`, and `ElicitationException` let clients respond to server elicitation requests.
+* Defer element loading to the first registry read: loaders now run at request time (first `has*`/`get*` call) instead of eagerly at `Builder::build()`, fixing empty registries under persistent runtimes (e.g. FrankenPHP worker mode) where a loader's data source is not ready at build time. Adds `Builder::setLazyLoading()` (default on), a public `Registry::load()`, and an optional `LoaderInterface` constructor argument on `Registry`.
+* [BC Break] Element loading is lazy by default: loader failures now surface on the first request rather than at `Builder::build()`, and `initialize` advertises capabilities from the configured sources rather than the loaded registry. Call `Builder::setLazyLoading(false)` to restore eager build-time loading.
+* Allow `[$instance, 'methodName']` as an element handler in `Builder::addTool()`, `addResource()`, `addResourceTemplate()`, and `addPrompt()`. Unblocks handlers with constructor dependencies that the container-less `new $className()` fallback cannot build.
+* Always emit an `items` schema for array tool parameters: untyped arrays get `items: {}` and nullable typed arrays (e.g. `string[]|null`) keep their element type. Fixes strict clients rejecting tools with "array type must have items" (#151).
+* Harden JSON-RPC input parsing: single-message vs batch is now decided from the decoded JSON type (object → single, list array → batch) instead of the raw first byte. Scalars, empty payloads, and non-object batch elements are surfaced as `InvalidInputMessageException` entries instead of triggering warnings or a `TypeError`.
+* Add `maxBatchSize` (default `100`) to `MessageFactory` — oversized JSON-RPC batches are rejected before any message is constructed, guarding against amplification.
+* Add `maxBodyBytes` (default 4 MiB) to `StreamableHttpTransport` — POST bodies exceeding the cap are rejected with `413`. Unknown-size/chunked bodies are read incrementally and stopped at the cap so they cannot exhaust memory.
+* Reject malformed `Mcp-Session-Id` headers with a `400` response: a repeated header or a value that is not a valid UUID is now rejected up front instead of surfacing as an uncaught `Uuid::fromString()` error.
+* Extract RFC 9728 metadata serving into `ProtectedResourceMetadataHandler`, a transport-neutral PSR-15 `RequestHandlerInterface` that can be mounted directly as a Symfony/Laravel controller; `ProtectedResourceMetadataMiddleware` now delegates to it (no BC break).
+
+0.6.0
+-----
+
+* Add `Builder::add(Tool|ResourceDefinition|ResourceTemplate|Prompt $definition, ElementHandlerInterface $handler)` for explicit registration of elements whose schema is only known at runtime.
+* Add handler interfaces `ToolHandlerInterface`, `ResourceHandlerInterface`, `ResourceTemplateHandlerInterface`, `PromptHandlerInterface`, and the `ElementHandlerInterface` marker.
+* [BC Break] Renamed `Mcp\Schema\Resource` to `Mcp\Schema\ResourceDefinition`. No alias.
+* [BC Break] Renamed `Mcp\Capability\Registry\Loader\ArrayLoader` to `Mcp\Capability\Registry\Loader\ReflectedElementLoader`.
+* [BC Break] Bump default protocol version to `2025-11-25`
+* Add support for MCP Apps extension in schema and server
+* Add `extensions` to `ServerCapabilities` and `ClientCapabilities` and `Builder::enableExtension()`
+* Allow overriding the default name pattern for Discovery
+* Add configurable session garbage collection (`gcProbability`/`gcDivisor`)
+* Add optional `title` field to `ResourceDefinition` and `ResourceTemplate` for MCP spec compliance
+* Add `ChainLoader` to compose multiple `LoaderInterface` implementations via explicit ordering.
+* Add `RegistryInterface::unregisterTool()`, `unregisterResource()`, `unregisterResourceTemplate()`, `unregisterPrompt()` — idempotent removals.
+* Add `RegistryInterface::hasTool()`, `hasResource()`, `hasResourceTemplate()`, `hasPrompt()` — by-name existence checks.
+* `DiscoveryLoader` now refreshes only its own previously written entries; manual registrations (via `Builder::addTool()` etc. or runtime `$registry->registerTool()` calls) survive rediscovery, and a same-name manual registration takes precedence over discovery on collision.
+* [BC Break] Removed `ElementReference::$isManual` public property and the `bool $isManual` parameter from all `*Reference` constructors. Origin tracking is no longer carried on the element; manual-over-discovered precedence is encoded by loader execution order.
+* [BC Break] `RegistryInterface::registerTool()`, `registerResource()`, `registerResourceTemplate()`, `registerPrompt()` lost their trailing `bool $isManual = false` parameter. Callers using positional arguments must drop the flag.
+* [BC Break] Removed `RegistryInterface::clear()`, `getDiscoveryState()`, `setDiscoveryState()`. Rediscovery now goes through `DiscoveryLoader::load()` directly.
+* `Registry::register*()` semantics changed to plain last-write-wins (overwrites silently) and the methods now return the stored `*Reference`. The previous "discovered registration is ignored when a manual one already exists" precedence rule still applies, but is now enforced by `DiscoveryLoader` via reference-identity tracking — and still emits a debug log when a discovery is skipped due to a conflicting registration.
+* Add optional `title` parameter to `Builder::addResource()` and `Builder::addResourceTemplate()` for MCP spec compliance
+* [BC Break] `Builder::addResource()` signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments must switch to named arguments.
+* [BC Break] `Builder::addResourceTemplate()` signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments must switch to named arguments.
+* Add `CorsMiddleware`, `DnsRebindingProtectionMiddleware`, and `ProtocolVersionMiddleware` for `StreamableHttpTransport`, composed automatically as the default stack via `StreamableHttpTransport::defaultMiddleware()`
+* [BC BREAK] `StreamableHttpTransport` constructor: `$corsHeaders` parameter removed; CORS is now configured via `CorsMiddleware`. The `$middleware` parameter is nullable — `null` (or omitted) installs the default stack; `[]` disables all defaults. Default `Access-Control-Allow-Origin` is no longer set (was `*`).
+* [BC Break] `ResourceDefinition::__construct()` signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments must switch to named arguments.
+* [BC Break] `ResourceTemplate::__construct()` signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments must switch to named arguments.
+* [BC Break] `McpResource` and `McpResourceTemplate` attribute signatures changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments must switch to named arguments.
+
+0.5.0
+-----
+
+* Add built-in authentication middleware for HTTP transport using OAuth
+* Add client component for building MCP clients
+* Add `Builder::setReferenceHandler()` to allow custom `ReferenceHandlerInterface` implementations (e.g. authorization decorators)
+* Add elicitation enum schema types per SEP-1330: `TitledEnumSchemaDefinition`, `MultiSelectEnumSchemaDefinition`, `TitledMultiSelectEnumSchemaDefinition`
+* [BC break] Make Symfony Finder component optional. Users would need to install `symfony/finder` now themselves
+* Add `LenientOidcDiscoveryMetadataPolicy` for identity providers that omit `code_challenge_methods_supported` (e.g. FusionAuth, Microsoft Entra ID)
+* Add OAuth 2.0 Dynamic Client Registration middleware (RFC 7591)
+* Add optional `title` field to `Prompt` and `McpPrompt` for MCP spec compliance
+* [BC Break] `Builder::addPrompt()` signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments for `$description` must switch to named arguments.
+* Add optional `title` field to `Tool` and `McpTool` for MCP spec compliance
+* [BC Break] `Tool::__construct()` signature changed — `$title` parameter added between `$name` and `$inputSchema`. Callers using positional arguments must switch to named arguments or pass `null` for `$title`.
+* [BC Break] `McpTool` attribute signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments for `$description` must switch to named arguments.
+* [BC Break] `Builder::addTool()` signature changed — `$title` parameter added between `$name` and `$description`. Callers using positional arguments for `$description` must switch to named arguments.
+
+0.4.0
+-----
+
+* Rename `Mcp\Server\Session\Psr16StoreSession` to `Mcp\Server\Session\Psr16SessionStore`
+* Add missing handlers for resource subscribe/unsubscribe and persist subscriptions via session
+* Introduce `SessionManager` to encapsulate session handling (replaces `SessionFactory`) and move garbage collection logic from `Protocol`.
+
+0.3.0
+-----
+
+* Add output schema support to MCP tools
+* Add validation of the input parameters given to a Tool.
+* Rename `Mcp\Capability\Registry\ResourceReference::$schema` to `Mcp\Capability\Registry\ResourceReference::$resource`.
+* Introduce `SchemaGeneratorInterface` and `DiscovererInterface` to allow custom schema generation and discovery implementations.
+* Remove `DocBlockParser::getSummary()` method, use `DocBlockParser::getDescription()` instead.
+
+0.2.2
+-----
+
+* Throw exception when trying to inject parameter with the unsupported names `$_session` or `$_request`.
+* `Throwable` objects are passed to log context instead of the exception message.
+
 0.2.1
 -----
 

CONTRIBUTING.md

@@ -0,0 +1,84 @@
+# Contributing
+
+Thanks for considering a contribution to the PHP SDK for the Model Context Protocol. This is a
+collaboration between [the PHP Foundation](https://thephp.foundation/) and the
+[Symfony project](https://symfony.com/), and it follows Symfony's conventions throughout.
+
+## Ways to contribute
+
+- **Report a bug** or **propose a feature** by [opening an issue](https://github.com/modelcontextprotocol/php-sdk/issues).
+  Check existing issues first — many spec-driven changes are already tracked under the relevant
+  `2026-07-28`-style release label.
+- **Send a pull request** for a fix, a new capability, or a docs improvement.
+- **Improve the guides** under `docs/` — see [Documentation](#documentation) below for how they're built.
+- **Help close a conformance gap** — `make conformance-tests` runs the official MCP conformance
+  suite against this SDK; a failing scenario there is a concrete, well-scoped contribution.
+
+## Development setup
+
+Requires PHP 8.1+.
+
+```bash
+composer install
+```
+
+## Before opening a pull request
+
+Run the full CI suite locally:
+
+```bash
+make ci
+```
+
+This runs, in order: `make cs` (PHP CS Fixer, auto-fixes style), `make phpstan` (static analysis),
+and `make tests` (unit + inspector tests). All three must pass. If your change touches
+protocol-observable behavior, also run:
+
+```bash
+make conformance-tests   # requires Docker
+```
+
+## Coding standards
+
+This project follows [Symfony's coding standards](https://symfony.com/doc/current/contributing/code/standards.html)
+and [backward compatibility promise](https://symfony.com/doc/current/contributing/code/bc.html). In short:
+
+See [CLAUDE.md](CLAUDE.md) for a fuller tour of the codebase's architecture and layout.
+
+## Tests
+
+New capabilities need unit tests (`tests/Unit/`) covering the core logic, and — for anything
+reachable over the wire — inspector tests (`tests/Inspector/`) for end-to-end coverage. If you're
+adding a documented pattern, consider adding or updating an example under `examples/`.
+
+## Documentation
+
+The guides under `docs/` are built with [Zensical](https://zensical.org/) in `--strict` mode,
+which fails the build on a broken internal link:
+
+```bash
+make docs-guides
+```
+
+Links between guide pages must be relative paths that resolve within `docs/` (e.g.
+`protocol-versions.md`, `../CLAUDE.md` will *not* resolve — Zensical only follows the `docs/` tree).
+For anything at the repo root (`CLAUDE.md`, `ROADMAP.md`, `CHANGELOG.md`), link to it by its GitHub
+URL instead, matching the pattern already used across `docs/`. The class-level API reference is
+generated separately by phpDocumentor (`make docs-api`) and isn't hand-written.
+
+## Versioning
+
+The SDK follows [Semantic Versioning](https://semver.org/) — see
+[SDK tier target](docs/sdk-tier.md#versioning) for what that means pre- and post-1.0, and how it
+lines up with Symfony's backward compatibility promise.
+
+## Licensing
+
+New contributions are licensed under Apache License, Version 2.0. Existing code predating this
+policy remains under the MIT License — see [LICENSE](LICENSE) for the details. By opening a pull
+request, you agree your contribution is provided under those terms.
+
+## Getting help
+
+If something is unclear or you want early feedback on an approach before writing code, open an
+issue or a draft pull request — that's the right place to ask, rather than guessing at scope.

LICENSE

@@ -1,11 +1,200 @@
+The MCP project is undergoing a licensing transition from the MIT License to the Apache License, Version 2.0 ("Apache-2.0"). All new code and specification contributions to the project are licensed under Apache-2.0. Documentation contributions (excluding specifications) are licensed under CC-BY-4.0.
+
+Contributions for which relicensing consent has been obtained are licensed under Apache-2.0. Contributions made by authors who originally licensed their work under the MIT License and who have not yet granted explicit permission to relicense remain licensed under the MIT License.
+
+No rights beyond those granted by the applicable original license are conveyed for such contributions.
+
+---
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to the Licensor for inclusion in the Work by the copyright
+      owner or by an individual or Legal Entity authorized to submit on behalf
+      of the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+---
+
 MIT License
 
+Copyright (c) 2024-2025 Model Context Protocol a Series of LF Projects, LLC.
+
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is furnished
-to do so, subject to the following conditions:
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
@@ -15,5 +204,13 @@ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+---
+
+Creative Commons Attribution 4.0 International (CC-BY-4.0)
+
+Documentation in this project (excluding specifications) is licensed under
+CC-BY-4.0. See https://creativecommons.org/licenses/by/4.0/legalcode for
+the full license text.

Makefile

@@ -1,4 +1,15 @@
-.PHONY: deps-stable deps-low cs phpstan tests unit-tests inspector-tests coverage ci ci-stable ci-lowest
+.PHONY: deps-stable deps-low cs phpstan tests unit-tests integration-tests inspector-tests coverage ci ci-stable ci-lowest conformance-tests conformance-server conformance-client conformance-draft conformance-draft-server conformance-draft-client docs docs-guides docs-api docs-serve
+
+# The 2026-07-28 scenarios ship on the `alpha` dist-tag; `latest` (0.1.x) has
+# none of them. Pinned to the same version CI runs (see
+# .github/workflows/pipeline.yaml), so a local pass means a green pipeline.
+CONFORMANCE_VERSION ?= 0.2.0-alpha.11
+CONFORMANCE = npx --yes @modelcontextprotocol/conformance@$(CONFORMANCE_VERSION)
+
+# The documentation toolchain is Python (Zensical, see requirements-docs.txt),
+# run through uv so no virtualenv has to be managed by hand:
+# https://docs.astral.sh/uv/getting-started/installation/
+DOCS_RUN = uv run --no-project --with-requirements requirements-docs.txt --
 
 deps-stable:
 	composer update --prefer-stable
@@ -18,9 +29,46 @@ tests:
 unit-tests:
 	vendor/bin/phpunit --testsuite=unit
 
+integration-tests:
+	vendor/bin/phpunit --testsuite=integration
+
 inspector-tests:
 	vendor/bin/phpunit --testsuite=inspector
 
+conformance-tests: conformance-server conformance-client
+
+conformance-server:
+	docker compose -f tests/Conformance/Fixtures/docker-compose.yml up -d
+	@echo "Waiting for server to start..."
+	@sleep 5
+	rm -rf tests/Conformance/results
+	cd tests/Conformance && $(CONFORMANCE) server --url http://localhost:8000/ --suite all --spec-version 2025-11-25 --expected-failures conformance-baseline-2025-11-25.yml --output-dir results || true
+	php tests/Conformance/score.php server 2025-11-25
+	docker compose -f tests/Conformance/Fixtures/docker-compose.yml down
+
+conformance-client:
+	rm -rf tests/Conformance/results
+	cd tests/Conformance && $(CONFORMANCE) client --command "php $(CURDIR)/tests/Conformance/client.php" --suite all --spec-version 2025-11-25 --expected-failures conformance-baseline-2025-11-25.yml --output-dir results || true
+	php tests/Conformance/score.php client 2025-11-25
+
+# --- 2026-07-28 (SEP-2575 stateless lifecycle) ------------------------------
+
+conformance-draft: conformance-draft-server conformance-draft-client
+
+conformance-draft-server:
+	docker compose -f tests/Conformance/Fixtures/docker-compose.yml up -d
+	@echo "Waiting for server to start..."
+	@sleep 5
+	rm -rf tests/Conformance/results-2026-07-28
+	cd tests/Conformance && $(CONFORMANCE) server --url http://localhost:8000/ --suite all --spec-version 2026-07-28 --expected-failures conformance-baseline-2026-07-28.yml --output-dir results-2026-07-28 || true
+	php tests/Conformance/score.php server 2026-07-28 results-2026-07-28
+	docker compose -f tests/Conformance/Fixtures/docker-compose.yml down
+
+conformance-draft-client:
+	rm -rf tests/Conformance/results-2026-07-28
+	cd tests/Conformance && $(CONFORMANCE) client --command "php $(CURDIR)/tests/Conformance/client.php" --suite all --spec-version 2026-07-28 --expected-failures conformance-baseline-2026-07-28.yml --output-dir results-2026-07-28 || true
+	php tests/Conformance/score.php client 2026-07-28 results-2026-07-28
+
 coverage:
 	XDEBUG_MODE=coverage vendor/bin/phpunit --testsuite=unit --coverage-html=coverage
 
@@ -29,3 +77,20 @@ ci: ci-stable
 ci-stable: deps-stable cs phpstan tests
 
 ci-lowest: deps-low cs phpstan tests
+
+# The published site is the guides (Zensical) with the phpDocumentor API
+# reference mounted at /api/. `zensical build` wipes site/, so it runs first.
+docs: docs-guides docs-api
+	rm -rf site/api
+	cp -a .phpdoc/build/api site/api
+
+docs-guides:
+	$(DOCS_RUN) zensical build --strict
+
+docs-api:
+	vendor/bin/phpdoc --no-interaction
+	@grep -q 'No errors have been found' .phpdoc/build/api/reports/errors.html || \
+		(echo "Documentation errors found. See .phpdoc/build/api/reports/errors.html" && exit 1)
+
+docs-serve:
+	$(DOCS_RUN) zensical serve

README.md

@@ -1,27 +1,31 @@
 # MCP PHP SDK
 
-The official PHP SDK for Model Context Protocol (MCP). It provides a framework-agnostic API for implementing MCP servers
-and clients in PHP.
+[![Latest Version](https://img.shields.io/packagist/v/mcp/sdk.svg)](https://packagist.org/packages/mcp/sdk)
+[![CI](https://github.com/modelcontextprotocol/php-sdk/actions/workflows/pipeline.yaml/badge.svg)](https://github.com/modelcontextprotocol/php-sdk/actions/workflows/pipeline.yaml)
+[![PHP Version](https://img.shields.io/packagist/php-v/mcp/sdk.svg)](https://packagist.org/packages/mcp/sdk)
+[![License](https://img.shields.io/packagist/l/mcp/sdk.svg)](LICENSE)
 
-> [!IMPORTANT]
-> This SDK is currently in active development with ongoing refinement of its architecture and features. While
-> functional, the API may experience changes as we work toward stabilization.
-> 
-> If you want to help us stabilize the SDK, please see the [issue tracker](https://github.com/modelcontextprotocol/php-sdk/issues).
+The official PHP SDK for the Model Context Protocol (MCP). It provides a framework-agnostic API for implementing MCP
+servers and clients in PHP — tools, resources, prompts, STDIO and HTTP transports, sessions, authorization, and both
+protocol eras (the `initialize` handshake and the stateless `2026-07-28` revision).
 
 This project represents a collaboration between [the PHP Foundation](https://thephp.foundation/) and the [Symfony project](https://symfony.com/). It adopts
 development practices and standards from the Symfony project, including [Coding Standards](https://symfony.com/doc/current/contributing/code/standards.html) and the
 [Backward Compatibility Promise](https://symfony.com/doc/current/contributing/code/bc.html).
 
-Until the first major release, this SDK is considered [experimental](https://symfony.com/doc/current/contributing/code/experimental.html).
+Until the first major release, this SDK is considered [experimental](https://symfony.com/doc/current/contributing/code/experimental.html), please see the [roadmap](./ROADMAP.md) for
+planned next steps and features.
 
-## Roadmap
+## Protocol Conformance
 
-**Features**
-- [ ] Stabilize server component with all needed handlers and functional tests
-- [ ] Extend documentation, including integration guides for popular frameworks
-- [ ] Implement Client component
-- [ ] Support multiple schema versions
+Measured weekly against the [MCP Conformance Test Framework](https://github.com/modelcontextprotocol/conformance),
+as passing checks out of total. The `2026-07-28` scores run against the framework's `alpha` releases, so they move as
+upstream publishes new scenarios.
+
+| Revision | Server | Client |
+|:--------:|:------:|:------:|
+| `2026-07-28` | [![Server conformance 2026-07-28](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/modelcontextprotocol/php-sdk/badges/server-conformance-2026-07-28.json)](https://github.com/modelcontextprotocol/php-sdk/actions/workflows/conformance-weekly.yaml) | [![Client conformance 2026-07-28](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/modelcontextprotocol/php-sdk/badges/client-conformance-2026-07-28.json)](https://github.com/modelcontextprotocol/php-sdk/actions/workflows/conformance-weekly.yaml) |
+| `2025-11-25` | [![Server conformance 2025-11-25](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/modelcontextprotocol/php-sdk/badges/server-conformance-2025-11-25.json)](https://github.com/modelcontextprotocol/php-sdk/actions/workflows/conformance-weekly.yaml) | [![Client conformance 2025-11-25](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/modelcontextprotocol/php-sdk/badges/client-conformance-2025-11-25.json)](https://github.com/modelcontextprotocol/php-sdk/actions/workflows/conformance-weekly.yaml) |
 
 ## Installation
 
@@ -29,30 +33,20 @@ Until the first major release, this SDK is considered [experimental](https://sym
 composer require mcp/sdk
 ```
 
-## Quick Start
+## Build a server
 
-This example demonstrates the most common usage pattern - a STDIO server using attribute discovery.
-
-### 1. Define Your MCP Elements
-
-Create a class with MCP capabilities using attributes:
+A server is a plain PHP class plus three lines of wiring:
 
 ```php
-<?php
-
-namespace App;
-
-use Mcp\Capability\Attribute\McpTool;
 use Mcp\Capability\Attribute\McpResource;
+use Mcp\Capability\Attribute\McpTool;
+use Mcp\Server;
+use Mcp\Server\Transport\StdioTransport;
 
-class CalculatorElements
+class Calculator
 {
     /**
-     * Adds two numbers together.
-     * 
-     * @param int $a The first number
-     * @param int $b The second number
-     * @return int The sum of the two numbers
+     * Adds two numbers.
      */
     #[McpTool]
     public function add(int $a, int $b): int
@@ -60,227 +54,88 @@ class CalculatorElements
         return $a + $b;
     }
 
-    /**
-     * Performs basic arithmetic operations.
-     */
-    #[McpTool(name: 'calculate')]
-    public function calculate(float $a, float $b, string $operation): float|string
+    #[McpResource(uri: 'config://calculator/settings')]
+    public function settings(): array
     {
-        return match($operation) {
-            'add' => $a + $b,
-            'subtract' => $a - $b,
-            'multiply' => $a * $b,
-            'divide' => $b != 0 ? $a / $b : 'Error: Division by zero',
-            default => 'Error: Unknown operation'
-        };
-    }
-
-    #[McpResource(
-        uri: 'config://calculator/settings',
-        name: 'calculator_config',
-        mimeType: 'application/json'
-    )]
-    public function getSettings(): array
-    {
-        return ['precision' => 2, 'allow_negative' => true];
+        return ['precision' => 2];
     }
 }
+
+exit(Server::builder()
+    ->setServerInfo('Calculator', '1.0.0')
+    ->setDiscovery(__DIR__, ['.'], excludeDirs: ['vendor'])
+    ->build()
+    ->run(new StdioTransport()));
 ```
 
-### 2. Create the Server Script
+The walkthrough in [First server](docs/get-started/first-server.md) explains each piece, and
+[Try it with the Inspector](docs/get-started/inspector.md) shows it running.
 
-Create your MCP server:
+## Build a client
 
 ```php
-#!/usr/bin/env php
-<?php
+use Mcp\Client;
+use Mcp\Client\Transport\StdioTransport;
 
-declare(strict_types=1);
-
-require_once __DIR__ . '/vendor/autoload.php';
-
-use Mcp\Server;
-use Mcp\Server\Transport\StdioTransport;
-
-$server = Server::builder()
-    ->setServerInfo('Calculator Server', '1.0.0')
-    ->setDiscovery(__DIR__, ['.'])
+$client = Client::builder()
+    ->setClientInfo('My Application', '1.0.0')
     ->build();
 
-$transport = new StdioTransport();
+$client->connect(new StdioTransport(command: 'php', args: ['/path/to/server.php']));
 
-$server->run($transport);
+$tools = $client->listTools();
+$result = $client->callTool('add', ['a' => 5, 'b' => 3]);
+
+$client->disconnect();
 ```
 
-### 3. Configure Your MCP Client
-
-Add to your client configuration (e.g., Claude Desktop's `mcp.json`):
-
-```json
-{
-    "mcpServers": {
-        "php-calculator": {
-            "command": "php",
-            "args": ["/absolute/path/to/your/server.php"]
-        }
-    }
-}
-```
-
-### 4. Test Your Server
-
-```bash
-# Test with MCP Inspector
-npx @modelcontextprotocol/inspector php /path/to/server.php
-
-# Your AI assistant can now call:
-# - add: Add two integers
-# - calculate: Perform arithmetic operations
-# - Read config://calculator/settings resource
-```
-
-## Key Features
-
-### Attribute-Based Discovery
-
-Define MCP elements using PHP attributes with automatic discovery:
-
-```php
-// Tool with automatic name and description from method
-#[McpTool]
-public function generateReport(): string { /* ... */ }
-
-// Tool with custom name
-#[McpTool(name: 'custom_name')]
-public function myMethod(): string { /* ... */ }
-
-// Resource with URI and metadata
-#[McpResource(uri: 'config://app/settings', mimeType: 'application/json')]
-public function getConfig(): array { /* ... */ }
-```
-
-### Manual Registration
-
-Register capabilities programmatically:
-
-```php
-$server = Server::builder()
-    ->addTool([MyClass::class, 'myMethod'], 'tool_name')
-    ->addResource([MyClass::class, 'getData'], 'data://config')
-    ->build();
-```
-
-### Multiple Transport Options
-
-**STDIO Transport** (Command-line integration):
-```php
-$transport = new StdioTransport();
-$server->run($transport);
-```
-
-**HTTP Transport** (Web-based communication):
-```php
-$transport = new StreamableHttpTransport($request, $responseFactory, $streamFactory);
-$response = $server->run($transport);
-// Handle $response in your web application
-```
-
-### Session Management
-
-By default, the SDK uses in-memory sessions. You can configure different session stores:
-
-```php
-use Mcp\Server\Session\FileSessionStore;
-use Mcp\Server\Session\InMemorySessionStore;
-use Mcp\Server\Session\Psr16StoreSession;
-use Symfony\Component\Cache\Psr16Cache;
-use Symfony\Component\Cache\Adapter\RedisAdapter;
-
-// Use default in-memory sessions with custom TTL
-$server = Server::builder()
-    ->setSession(ttl: 7200) // 2 hours
-    ->build();
-
-// Override with file-based storage
-$server = Server::builder()
-    ->setSession(new FileSessionStore(__DIR__ . '/sessions'))
-    ->build();
-
-// Override with in-memory storage and custom TTL
-$server = Server::builder()
-    ->setSession(new InMemorySessionStore(3600))
-    ->build();
-
-// Override with PSR-16 cache-based storage
-// Requires psr/simple-cache and symfony/cache (or any other PSR-16 implementation)
-// composer require psr/simple-cache symfony/cache
-$redisAdapter = new RedisAdapter(
-    RedisAdapter::createConnection('redis://localhost:6379'),
-    'mcp_sessions'
-);
-
-$server = Server::builder()
-    ->setSession(new Psr16StoreSession(
-        cache: new Psr16Cache($redisAdapter),
-        prefix: 'mcp-',
-        ttl: 3600
-    ))
-    ->build();
-```
-
-### Discovery Caching
-
-Use any PSR-16 cache implementation to cache discovery results and avoid running discovery on every server start:
-
-```php
-use Symfony\Component\Cache\Adapter\FilesystemAdapter;
-use Symfony\Component\Cache\Psr16Cache;
-
-$cache = new Psr16Cache(new FilesystemAdapter('mcp-discovery'));
-
-$server = Server::builder()
-    ->setDiscovery(
-        basePath: __DIR__,
-        scanDirs: ['.', 'src'],      // Default: ['.', 'src']
-        excludeDirs: ['vendor'],     // Default: ['vendor', 'node_modules']
-        cache: $cache
-    )
-    ->build();
-```
+See [Connecting to a server](docs/client/connecting.md) for transports, timeouts, and the
+handlers that answer server-initiated requests.
 
 ## Documentation
 
-**Core Concepts:**
-- [Server Builder](docs/server-builder.md) - Complete ServerBuilder reference and configuration
-- [Transports](docs/transports.md) - STDIO and HTTP transport setup and usage
-- [MCP Elements](docs/mcp-elements.md) - Creating tools, resources, and prompts
-- [Client Communication](docs/client-communication.md) - Communicating back to the client from server-side
+The full documentation is published at **[php.sdk.modelcontextprotocol.io](https://php.sdk.modelcontextprotocol.io/)**.
 
-**Learning:**
-- [Examples](docs/examples.md) - Comprehensive example walkthroughs
+- **[Get started](docs/get-started/index.md)** — Install the SDK and build your first server
+- **[Servers](docs/servers/index.md)** — Tools, resources, resource templates, prompts, and how to register them
+- **[Inside your handler](docs/handlers/index.md)** — Talking back to the client, logging, and asking for input
+- **[Running your server](docs/run/index.md)** — Server builder, STDIO and HTTP transports, framework integration, sessions, authorization
+- **[Clients](docs/client/index.md)** — Client SDK for connecting to and communicating with MCP servers
+- **[Protocol versions](docs/protocol-versions.md)** — The two protocol eras, and what revision `2026-07-28` changed
+- **[Advanced](docs/advanced/index.md)** — Events, protocol extensions (including MCP Apps), and custom message handlers
+- **[Examples](docs/examples.md)** — Runnable server and client examples
+- **[API Reference](https://php.sdk.modelcontextprotocol.io/api/)** — Generated class reference
 
-**External Resources:**
-- [Model Context Protocol documentation](https://modelcontextprotocol.io)
-- [Model Context Protocol specification](https://spec.modelcontextprotocol.io)
-- [Officially supported servers](https://github.com/modelcontextprotocol/servers)
+## External Resources
+
+- **[Model Context Protocol Documentation](https://modelcontextprotocol.io)** — Official MCP documentation
+- **[Model Context Protocol Specification](https://spec.modelcontextprotocol.io)** — Protocol specification
+- **[Officially Supported Servers](https://github.com/modelcontextprotocol/servers)** — Reference server implementations
 
 ## PHP Libraries Using the MCP SDK
 
-* [pronskiy/mcp](https://github.com/pronskiy/mcp) - Additional DX layer
-* [symfony/mcp-bundle](https://github.com/symfony/mcp-bundle) - Symfony integration bundle
-* [josbeir/cakephp-synapse](https://github.com/josbeir/cakephp-synapse) - CakePHP integration plugin
+- [api-platform/mcp](https://github.com/api-platform/mcp) — MCP integration for API Platform
+- [bnomei/kirby-mcp](https://github.com/bnomei/kirby-mcp) — MCP server for the Kirby CMS
+- [drupal/mcp_server](https://www.drupal.org/project/mcp_server) — MCP server for Drupal exposing configuration and entities as MCP elements
+- [josbeir/cakephp-synapse](https://github.com/josbeir/cakephp-synapse) — CakePHP plugin exposing application functionality over MCP
+- [nette/mcp-inspector](https://github.com/nette/mcp-inspector) — MCP server for introspecting Nette applications
+- [symfony/ai-mate](https://github.com/symfony/ai-mate) — AI development assistant MCP server for Symfony projects
+- [symfony/mcp-bundle](https://github.com/symfony/mcp-bundle) — Symfony integration bundle
+
+Building something on top of the SDK? Open a pull request to add it to this list.
 
 ## Contributing
 
 We are passionate about supporting contributors of all levels of experience and would love to see you get involved in
-the project. See the [contributing guide](CONTRIBUTING.md) to get started before you [report issues](https://github.com/modelcontextprotocol/php-sdk/issues) and [send pull requests](https://github.com/modelcontextprotocol/php-sdk/pulls).
+the project. Start by [reporting issues](https://github.com/modelcontextprotocol/php-sdk/issues) or
+[sending pull requests](https://github.com/modelcontextprotocol/php-sdk/pulls). See
+[CONTRIBUTING.md](CONTRIBUTING.md) for development setup, coding standards, and what to run before
+opening a PR.
 
 ## Credits
 
-The starting point for this SDK was the [PHP-MCP](https://github.com/php-mcp/server) project, initiated by
-[Kyrian Obikwelu](https://github.com/CodeWithKyrian), and the [Symfony AI initiative](https://github.com/symfony/ai). We are grateful for the work
-done by both projects and their contributors, which created a solid foundation for this SDK.
+The starting point for this SDK was the [PHP-MCP](https://github.com/php-mcp/server) project, initiated by [Kyrian Obikwelu](https://github.com/CodeWithKyrian), and the [Symfony AI initiative](https://github.com/symfony/ai). We are grateful for the work done by both projects and their contributors, which created a solid foundation for this SDK.
 
 ## License
 
-This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.
+This project is licensed under the Apache License, Version 2.0 for new contributions, with existing code under the MIT License — see the [LICENSE](LICENSE) file for details.

ROADMAP.md

@@ -0,0 +1,21 @@
+# Roadmap
+
+This roadmap is a living document that outlines the planned features and improvements for our project.
+
+## Goals for the First Major Release
+
+- **Server**
+- [x] Implement full support for elicitations
+- [ ] Implement OAuth2 authentication for server
+- **Client**
+- [x] Implement client-side support
+- [x] Implement client examples and documentation
+- [ ] Implement OAuth2 authentication for client
+- **Schema**
+- [ ] Implement schema generation based on TS or JSON Schema
+- [ ] Achieve full spec conformance
+- **Extensions**
+- [ ] Implement the Tasks extension
+- **Architecture**
+- [ ] Split the SDK into multiple packages
+

SECURITY.md

@@ -0,0 +1,21 @@
+# Security Policy
+
+Thank you for helping keep the Model Context Protocol and its ecosystem secure.
+
+## Reporting Security Issues
+
+If you discover a security vulnerability in this repository, please report it through
+the [GitHub Security Advisory process](https://docs.github.com/en/code-security/security-advisories/guidance-on-reporting-and-writing-information-about-vulnerabilities/privately-reporting-a-security-vulnerability)
+for this repository.
+
+Please **do not** report security vulnerabilities through public GitHub issues, discussions,
+or pull requests.
+
+## What to Include
+
+To help us triage and respond quickly, please include:
+
+- A description of the vulnerability
+- Steps to reproduce the issue
+- The potential impact
+- Any suggested fixes (optional)

adr/0001-oauth-authorization-server-out-of-scope.md

@@ -0,0 +1,97 @@
+# 0001 — The MCP server is an OAuth Resource Server, not an Authorization Server
+
+- Status: Accepted
+- Date: 2026-06-15
+
+## Context
+
+OAuth 2.1 defines three distinct roles:
+
+| Role | What it does | Status in this SDK | Scope |
+|------|--------------|--------------------|-------|
+| Resource Server | Validates incoming bearer tokens, serves Protected Resource Metadata (RFC 9728), emits `WWW-Authenticate` | Shipped (`AuthorizationMiddleware`, `JwtTokenValidator`, `ProtectedResourceMetadata`) | **IN scope** |
+| Delegation / proxy to an upstream AS | Forwards `/authorize` and `/token` to your existing IdP | Shipped (`OAuthProxyMiddleware`) | **IN scope — delegation ONLY** |
+| Authorization Server / Identity Provider (IdP) | Mints its own tokens, registers clients, runs login and consent | Absent | **OUT of scope** |
+
+The SDK repeatedly receives pull requests that move it toward becoming a full OAuth 2.1
+**authorization server** — asking the MCP server to mint its own access and refresh tokens,
+register clients, and run login and consent flows, that is, to become an Identity Provider.
+The most explicit example is [#373](https://github.com/modelcontextprotocol/php-sdk/pull/373)
+("[Server] Add native OAuth 2.1 authorization server", ~3,400 lines across 50+ files), but the
+direction has crept in incrementally rather than in one PR.
+
+A contributing factor is that the SDK already exposes the *authorization-server endpoints in
+proxy form*, and that surface has grown:
+[#221](https://github.com/modelcontextprotocol/php-sdk/pull/221) added the OAuth resource-server
+middleware, and [#269](https://github.com/modelcontextprotocol/php-sdk/pull/269) added Dynamic
+Client Registration (RFC 7591). Today `OAuthProxyMiddleware` answers `/authorize`, `/token`, and
+`/.well-known/oauth-authorization-server`, and DCR endpoints exist. The shape of that surface
+invites contributors to "finish the job" by backing those endpoints with a real token issuer.
+It is not scaffolding to be completed — it is a delegating proxy, and that is the whole of its
+intent.
+
+## Decision
+
+**The MCP server is an OAuth 2.1 Resource Server that MAY delegate to an upstream
+authorization server. It will NOT issue tokens or act as an Identity Provider.**
+
+Concretely:
+
+- The SDK validates bearer tokens, serves RFC 9728 Protected Resource Metadata, and emits
+  `WWW-Authenticate` challenges. This is the Resource Server role and is fully supported.
+- The SDK MAY delegate `/authorize` and `/token` to an upstream authorization server via
+  `OAuthProxyMiddleware`. This is delegation only: the middleware redirects the browser to
+  the upstream `/authorize` endpoint and proxies `/token` requests to the upstream token
+  endpoint. It never mints, signs, stores, or rotates tokens of its own.
+- The SDK will NOT implement an authorization server: no token issuance, no token signing or
+  key management, no login UI, no consent UI, no authorization-code or refresh-token storage,
+  no first-party Dynamic Client Registration acting as an issuer.
+
+Pull requests that add authorization-server / IdP behavior are declined by reference to this
+ADR.
+
+## Rationale
+
+- **Security liability.** Issuing tokens means owning signing-key generation, storage, and
+  rotation; authorization-code and refresh-token persistence; refresh-token rotation and
+  replay detection; and consent. A defect in any of these is a credential-issuance
+  vulnerability affecting every consumer of the SDK. This is precisely the surface an MCP SDK
+  should not own.
+- **RFC footprint.** A correct authorization server must implement and keep current with
+  RFC 6749 (OAuth 2.0), RFC 7591 (Dynamic Client Registration), RFC 8414 (Authorization
+  Server Metadata), PKCE (RFC 7636), and refresh-token rotation guidance, among others. That
+  is an open-ended maintenance and conformance burden far outside the SDK's purpose.
+- **Mature implementations already exist.** Token issuance is a solved problem.
+  `league/oauth2-server` provides it as a PHP library, and every production IdP — Keycloak,
+  Auth0, Microsoft Entra ID, Okta — provides it as a service. Re-implementing it inside an
+  MCP SDK adds risk without adding value.
+
+## Boundary statement
+
+`OAuthProxyMiddleware` **delegates** to an upstream IdP. It is **not** authorization-server
+scaffolding to be completed. Backing its `/authorize` and `/token` endpoints with a
+first-party token issuer is out of scope and will be declined.
+
+## Consequences
+
+- The supported authorization architecture is: an external authorization server (your IdP or
+  `league/oauth2-server` running in your own application) issues tokens; the MCP server
+  validates them as a Resource Server and optionally proxies the OAuth flow to that upstream.
+- Contributors get a single, citable ruling for why authorization-server PRs are declined,
+  reducing repeated large-PR churn.
+- Resource Server and proxy/delegation features remain welcome and supported.
+
+## Alternatives / what to do instead
+
+If you need an authorization server (token issuance, client registration, login, consent), do
+**not** add it to this SDK. Instead:
+
+- **Front the MCP server with an existing IdP** — Keycloak, Auth0, Microsoft Entra ID, or
+  Okta. Point `JwtTokenValidator` and `ProtectedResourceMetadata` at that issuer, and
+  optionally use `OAuthProxyMiddleware` to delegate `/authorize` and `/token` to it.
+- **Run `league/oauth2-server` in your own application**, behind the SDK's existing proxy and
+  validator seams. The MCP server validates the tokens it issues; it does not issue them
+  itself.
+
+See [`../docs/run/authorization.md`](../docs/run/authorization.md) for the supported Resource Server
+and delegation setup.

adr/README.md

@@ -0,0 +1,10 @@
+# Architecture Decision Records
+
+This directory holds Architecture Decision Records (ADRs): short documents that capture a
+significant architectural decision, the context that led to it, and its consequences. They
+exist so a decision can be cited once and referenced thereafter — for example, when declining
+a pull request that conflicts with an accepted decision.
+
+## Records
+
+- [0001 — The MCP server is an OAuth Resource Server, not an Authorization Server](0001-oauth-authorization-server-out-of-scope.md)

composer.json

@@ -1,8 +1,8 @@
 {
   "name": "mcp/sdk",
-  "type": "library",
   "description": "Model Context Protocol SDK for Client and Server applications in PHP",
-  "license": "MIT",
+  "license": "Apache-2.0",
+  "type": "library",
   "authors": [
     {
       "name": "Christopher Hertel",
@@ -22,27 +22,40 @@
     "ext-fileinfo": "*",
     "opis/json-schema": "^2.4",
     "php-http/discovery": "^1.20",
-    "phpdocumentor/reflection-docblock": "^5.6",
+    "phpdocumentor/reflection-docblock": "^5.6 || ^6.0",
     "psr/clock": "^1.0",
-    "psr/container": "^2.0",
+    "psr/container": "^1.0 || ^2.0",
     "psr/event-dispatcher": "^1.0",
+    "psr/http-client": "^1.0",
     "psr/http-factory": "^1.1",
-    "psr/http-message": "^2.0",
+    "psr/http-message": "^1.1 || ^2.0",
+    "psr/http-server-handler": "^1.0",
+    "psr/http-server-middleware": "^1.0",
     "psr/log": "^1.0 || ^2.0 || ^3.0",
-    "symfony/finder": "^5.4 || ^6.4 || ^7.3 || ^8.0",
+    "symfony/deprecation-contracts": "^2.5 || ^3.0",
     "symfony/uid": "^5.4 || ^6.4 || ^7.3 || ^8.0"
   },
+  "suggest": {
+    "symfony/finder": "Required for file-based discovery."
+  },
   "require-dev": {
+    "ext-openssl": "*",
+    "composer/semver": "^3.0",
+    "firebase/php-jwt": "^6.10 || ^7.0",
+    "laminas/laminas-httphandlerrunner": "^2.12",
+    "nyholm/psr7": "^1.8",
+    "nyholm/psr7-server": "^1.1",
+    "phar-io/composer-distributor": "^1.0.2",
     "php-cs-fixer/shim": "^3.91",
+    "phpdocumentor/shim": "^3",
     "phpstan/phpstan": "^2.1",
     "phpunit/phpunit": "^10.5",
     "psr/simple-cache": "^2.0 || ^3.0",
     "symfony/cache": "^5.4 || ^6.4 || ^7.3 || ^8.0",
     "symfony/console": "^5.4 || ^6.4 || ^7.3 || ^8.0",
-    "symfony/process": "^5.4 || ^6.4 || ^7.3 || ^8.0",
-    "nyholm/psr7": "^1.8",
-    "nyholm/psr7-server": "^1.1",
-    "laminas/laminas-httphandlerrunner": "^2.12"
+    "symfony/finder": "^5.4 || ^6.4 || ^7.3 || ^8.0",
+    "symfony/http-client": "^5.4 || ^6.4 || ^7.3 || ^8.0",
+    "symfony/process": "^5.4 || ^6.4 || ^7.3 || ^8.0"
   },
   "autoload": {
     "psr-4": {
@@ -53,23 +66,32 @@
     "psr-4": {
       "Mcp\\Example\\Server\\CachedDiscovery\\": "examples/server/cached-discovery/",
       "Mcp\\Example\\Server\\ClientCommunication\\": "examples/server/client-communication/",
+      "Mcp\\Example\\Server\\ClientLogging\\": "examples/server/client-logging/",
       "Mcp\\Example\\Server\\CombinedRegistration\\": "examples/server/combined-registration/",
+      "Mcp\\Example\\Server\\Elicitation\\": "examples/server/elicitation/",
       "Mcp\\Example\\Server\\ComplexToolSchema\\": "examples/server/complex-tool-schema/",
+      "Mcp\\Example\\Server\\Conformance\\": "examples/server/conformance/",
       "Mcp\\Example\\Server\\CustomDependencies\\": "examples/server/custom-dependencies/",
       "Mcp\\Example\\Server\\CustomMethodHandlers\\": "examples/server/custom-method-handlers/",
       "Mcp\\Example\\Server\\DiscoveryCalculator\\": "examples/server/discovery-calculator/",
       "Mcp\\Example\\Server\\DiscoveryUserProfile\\": "examples/server/discovery-userprofile/",
       "Mcp\\Example\\Server\\EnvVariables\\": "examples/server/env-variables/",
       "Mcp\\Example\\Server\\ExplicitRegistration\\": "examples/server/explicit-registration/",
+      "Mcp\\Example\\Server\\McpApps\\": "examples/server/mcp-apps/",
+      "Mcp\\Example\\Server\\OAuthKeycloak\\": "examples/server/oauth-keycloak/",
+      "Mcp\\Example\\Server\\OAuthMicrosoft\\": "examples/server/oauth-microsoft/",
       "Mcp\\Example\\Server\\SchemaShowcase\\": "examples/server/schema-showcase/",
-      "Mcp\\Example\\Server\\ClientLogging\\": "examples/server/client-logging/",
       "Mcp\\Tests\\": "tests/"
-    }
+    },
+    "classmap": [
+      "tests/Unit/Capability/Discovery/Fixtures/AlternativeFileNameToolHandler.class.inc"
+    ]
   },
   "config": {
-    "sort-packages": true,
     "allow-plugins": {
-      "php-http/discovery": false
-    }
+      "php-http/discovery": false,
+      "phpdocumentor/shim": true
+    },
+    "sort-packages": true
   }
 }