Clients

The plugin also connects out: your application becomes the MCP client of a first-party or third-party server, for example a chat app answering questions about a user's repositories. No server of your own is needed.

Connecting

public function clients(): array
{
    return [
        Client::web('https://api.githubcopilot.com/mcp/'),
        Client::local('php', ['mcp', 'start', 'weather']),
    ];
}

The local form takes the command plus its arguments: typically the PHP binary with bin/cake.php mcp start <handle> (see Commands). Connections are lazy. The first list/call dials. Manage manually when needed:

public function probe(Client $client): array
{
    $client->connect();
    $client->ping();

    if ($client->connected()) {
        return [$client->capabilities(), $client->serverInfo()];
    }

    $client->disconnect();

    return [];
}

Tune the request timeout per client:

public function timedClient(): Client
{
    return Client::web('https://api.githubcopilot.com/mcp/')->withTimeout(30);
}

Named clients

public function registerClients(): void
{
    ClientManager::getInstance()->registerClient(
        'github',
        fn() => Client::web('https://api.githubcopilot.com/mcp/'),
    );
}

Resolve anywhere by name; the manager disconnects at process shutdown:

public function github(): Client
{
    return ClientManager::getInstance()->client('github');
}

Authentication

Bearer tokens attach directly: pass a string, or a closure resolving the current user's token at call time:

public function bearerClient(string $token): Client
{
    return Client::web('https://api.githubcopilot.com/mcp/')->withToken($token);
}

For per-user OAuth against an external service, pair withOAuth (your app's client credentials) with withToken (the connected user's saved access token), then register the account-linking routes so the connect route sends the user to the consent screen and the callback persists the resulting TokenSet:

public function linkAccount(RouteBuilder $routes): void
{
    Registrar::getInstance()->oAuthRoutesFor(
        $routes,
        'projects',
        function (string $client, TokenSet $token): Response {
            return (new Response())->withLocation('/chat');
        },
        ['auth'],
    );
}

This registers connect, callback, and client-metadata routes under mcp.oauth.{client}.*. Store tokens encrypted, keep refreshToken/expiresAt for renewals.

Tools, prompts, resources

public function catalog(Client $client): array
{
    $names = [];

    foreach ($client->tools() as $tool) {
        $names[] = [$tool->name, $tool->title, $tool->description];
    }

    return $names;
}

Pagination is automatic; tools(limit: 10) caps the listing. Invoke by name. The ToolResult exposes text, error state, and structured content:

public function issues(Client $client): ToolResult
{
    return $client->callTool('list_issues', [
        'owner' => 'octocat',
        'repo' => 'hello-world',
    ]);
}

The ToolResult exposes text, error state, and structured content (text(), isError, structuredContent). Or call from a listed instance: $tools['list_issues']->call([...]). Prompts (prompts() / getPrompt()) and resources (resources() / readResource($uri)) follow the same list-then-use shape with the same limit option.

Where next

• Servers — expose your own server instead
• MCP tools — MCP tools inside agents