Connecting and discovery¶

How to attach a transport and read what the server offers. connect() starts the session, and discover() asks the server to describe itself.

$client->connect($transport);
$result = $client->discover();

discover() sends a server/discover request and records the server's advertised info and capabilities. It is optional. A client may call it to learn the server's identity and capabilities, but no discovery is required before typed requests. After connect(), the client can call listTools(), callTool(), and the other typed methods directly.

The discover result¶

discover() returns a DiscoverResult:

The server's identity rides the result _meta rather than the result body, so serverInfo is nullable. A server may decline to identify itself. The value is self-reported and unverified. Treat it as display and logging material, never as a behavioural or security signal.

$result = $client->discover();
echo $result->meta->serverInfo?->name ?? '(anonymous)', "\n";
echo 'Protocol versions: ', implode(', ', $result->supportedVersions), "\n";

What the client remembers¶

After discover(), getServerInfo() returns the server's Implementation block (name, version, title, …). It returns null before discovery runs, and also when the server identified itself on neither leg.

$info = $client->getServerInfo();
echo $info?->name, ' ', $info?->version;

getServerCapabilities() returns the server's advertised ServerCapabilities, or null before discovery has run for the attached server. Use it to check what the server supports before you issue a typed request (see Typed requests).

if (null !== $client->getServerCapabilities()?->tools) {
    $tools = $client->listTools();
}

Disconnecting¶

connect() attaches and starts the transport. disconnect() is its inverse. It closes the transport and detaches it, so the client can connect() to a new transport afterwards. It does nothing when the client is not connected.

disconnect() also forgets what the old server advertised. getServerInfo() and getServerCapabilities() return null again, and the next server is gated on its own discover() rather than the last one's. Calling connect() twice, or using the client before connect(), throws LogicException.

$client->disconnect();