php-sdk/examples/server/discovery-userprofile/McpElements.php
Alex Rothberg fc456125e2
[Schema] Add resource_link content block (#400)
* Add resource_link content block

The spec's `resource_link` content type (protocol revision 2025-06-18,
still present in 2025-11-25) had no corresponding schema class: it lets a
tool result or prompt message reference a resource by URI/name without
embedding its full contents, the way `EmbeddedResource` does. Without it,
tools returning many or large resource references (e.g. search results
over a DAM) are stuck smuggling URIs through text/structured content.

Add `Mcp\Schema\Content\ResourceLink`, mirroring the spec's `Resource`
shape (uri, name, title, description, mimeType, annotations, size, icons,
_meta) with a fixed `type: "resource_link"`, following the conventions of
the sibling `EmbeddedResource`/`ResourceDefinition` classes.

Register it everywhere `resource` content blocks are (de)serialized by
type per the spec's `ContentBlock` union:
- `CallToolResult::fromArray()`
- `PromptMessage` (constructor type, `fromArray()`, phpstan types)
- `PromptResultFormatter` (typed-array and direct-instance paths)

`SamplingMessage`/`CreateSamplingMessageResult` are intentionally left
unchanged: the spec's `SamplingMessageContentBlock` does not include
`ResourceLink`.

Fixes #399

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Add resource_link example coverage to discovery-userprofile

Add a lookup_user tool to the discovery-userprofile example: given a
userId, it returns a short text summary plus a resource_link pointing
at the existing user://{userId}/profile resource template, instead of
embedding the profile. This mirrors the PR's motivating use case (a
tool referencing many/large resources by URI rather than inlining
them) and exercises resource_link through the example's own inspector
snapshot tests (tools_call-lookup_user[_not_found], tools_list).

Wiring this up surfaced a real bug: ToolReference::extractStructuredContent()
passed any raw array return value straight through as structuredContent,
even when it held Content instances (e.g. the TextContent/ResourceLink
pair above). That serializes to a JSON list, which fails the spec's
requirement that structuredContent be an object - the inspector's MCP
client rejected the tool call outright until fixed. Skip structuredContent
extraction whenever the raw result contains a Content item, since those
are already represented in `content` and were never meant to double as
structured data.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Alex Rothberg <51059+cancan101@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-08-14 23:20:56 +02:00

193 lines
6.4 KiB
PHP

<?php
/*
* This file is part of the official PHP MCP SDK.
*
* A collaboration between Symfony and the PHP Foundation.
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Mcp\Example\Server\DiscoveryUserProfile;
use Mcp\Capability\Attribute\CompletionProvider;
use Mcp\Capability\Attribute\McpPrompt;
use Mcp\Capability\Attribute\McpResource;
use Mcp\Capability\Attribute\McpResourceTemplate;
use Mcp\Capability\Attribute\McpTool;
use Mcp\Exception\PromptGetException;
use Mcp\Exception\ResourceReadException;
use Mcp\Schema\Content\Content;
use Mcp\Schema\Content\ResourceLink;
use Mcp\Schema\Content\TextContent;
use Psr\Log\LoggerInterface;
/**
* @phpstan-type User array{name: string, email: string, role: string}
*/
final class McpElements
{
/**
* Simulate a simple user database.
*
* @var array<int, User>
*/
private array $users = [
'101' => ['name' => 'Alice', 'email' => 'alice@example.com', 'role' => 'admin'],
'102' => ['name' => 'Bob', 'email' => 'bob@example.com', 'role' => 'user'],
'103' => ['name' => 'Charlie', 'email' => 'charlie@example.com', 'role' => 'user'],
];
public function __construct(
private readonly LoggerInterface $logger,
) {
$this->logger->debug('DiscoveryUserProfile McpElements instantiated.');
}
/**
* Retrieves the profile data for a specific user.
*
* @param string $userId the ID of the user (from URI)
*
* @return User user profile data
*
* @throws ResourceReadException if the user is not found
*/
#[McpResourceTemplate(
uriTemplate: 'user://{userId}/profile',
name: 'user_profile',
description: 'Get profile information for a specific user ID.',
mimeType: 'application/json'
)]
public function getUserProfile(
#[CompletionProvider(values: ['101', '102', '103'])]
string $userId,
): array {
$this->logger->info('Reading resource: user profile', ['userId' => $userId]);
if (!isset($this->users[$userId])) {
throw new ResourceReadException("User not found for ID: {$userId}");
}
return $this->users[$userId];
}
/**
* Retrieves a list of all known user IDs.
*
* @return int[] list of user IDs
*/
#[McpResource(
uri: 'user://list/ids',
name: 'user_id_list',
description: 'Provides a list of all available user IDs.',
mimeType: 'application/json'
)]
public function listUserIds(): array
{
$this->logger->info('Reading resource: user ID list');
return array_keys($this->users);
}
/**
* Looks up a user and returns a reference to their profile resource.
*
* Rather than embedding the full profile (as `resources/read` on
* `user://{userId}/profile` would), this returns a `resource_link` block
* pointing at that resource template so the caller can fetch it
* separately if needed. This mirrors how a tool like a search returning
* many hits would reference each matching resource by URI instead of
* inlining every one of them.
*
* @param string $userId the ID of the user to look up
*
* @return Content[] a short summary plus a resource_link to the user's profile
*/
#[McpTool(name: 'lookup_user')]
public function lookupUser(
#[CompletionProvider(values: ['101', '102', '103'])]
string $userId,
): array {
$this->logger->info('Executing tool: lookup_user', ['userId' => $userId]);
if (!isset($this->users[$userId])) {
return [new TextContent("User ID {$userId} not found.")];
}
$user = $this->users[$userId];
return [
new TextContent("Found user {$user['name']} ({$user['role']})."),
new ResourceLink(
uri: "user://{$userId}/profile",
name: 'user_profile',
description: "Full profile for {$user['name']}.",
mimeType: 'application/json',
),
];
}
/**
* Sends a welcome message to a user.
* (This is a placeholder - in a real app, it might queue an email).
*
* @param string $userId the ID of the user to message
* @param string|null $customMessage an optional custom message part
*
* @return array<string, bool|string> status of the operation
*/
#[McpTool(name: 'send_welcome')]
public function sendWelcomeMessage(string $userId, ?string $customMessage = null): array
{
$this->logger->info('Executing tool: send_welcome', ['userId' => $userId]);
if (!isset($this->users[$userId])) {
return ['success' => false, 'error' => "User ID {$userId} not found."];
}
$user = $this->users[$userId];
$message = "Welcome, {$user['name']}!";
if ($customMessage) {
$message .= ' '.$customMessage;
}
// Simulate sending
$this->logger->info("Simulated sending message to {$user['email']}: {$message}");
return ['success' => true, 'message_sent' => $message];
}
/**
* @return array<string, bool|string>
*/
#[McpTool(name: 'test_tool_without_params')]
public function testToolWithoutParams(): array
{
return ['success' => true, 'message' => 'Test tool without params'];
}
/**
* Generates a prompt to write a bio for a user.
*
* @param string $userId the user ID to generate the bio for
* @param string $tone Desired tone (e.g., 'formal', 'casual').
*
* @return array<string, string>[] prompt messages
*
* @throws PromptGetException if user not found
*/
#[McpPrompt(name: 'generate_bio_prompt')]
public function generateBio(
#[CompletionProvider(provider: UserIdCompletionProvider::class)]
string $userId,
string $tone = 'professional',
): array {
$this->logger->info('Executing prompt: generate_bio', ['userId' => $userId, 'tone' => $tone]);
if (!isset($this->users[$userId])) {
throw new PromptGetException("User not found for bio prompt: {$userId}");
}
$user = $this->users[$userId];
return [
['role' => 'user', 'content' => "Write a short, {$tone} biography for {$user['name']} (Role: {$user['role']}, Email: {$user['email']}). Highlight their role within the system."],
];
}
}