e0b9c1a26fOne handler asks the user something on any revision now. Where the client can be asked mid-request it still is; where it cannot, the ask becomes the input_required result that revision carries and the same call returns the answer once the client re-sends it. Costs one handler entry per ask, so side effects belong after the last question. Answers from earlier rounds travel in the requestState, which is why asking more than once needs Builder::setRequestState(). sample() and listRoots() still raise a LogicException there: that revision removed them outright.
1.9 KiB
1.9 KiB
Inside your handler
The methods you register are ordinary PHP methods, but they are not cut off from the
protocol. Type-hint a Mcp\Server\RequestContext argument anywhere in the signature and
the SDK passes it in — that object is the way back to the client mid-request.
use Mcp\Capability\Attribute\McpTool;
use Mcp\Schema\Content\TextContent;
use Mcp\Server\RequestContext;
#[McpTool]
public function summarize(string $text, RequestContext $context): string
{
$context->getClientLogger()->info(\sprintf('Summarizing %d characters', \strlen($text)));
$result = $context->getClientGateway()->sample("Summarize:\n\n".$text, 500);
// `content` is TextContent|ImageContent|AudioContent (or ToolUseContent
// blocks when the client samples with tools)
return $result->content instanceof TextContent ? $result->content->text : '';
}
Two caveats on this example: clients drop log messages below warning unless they raise
the level first (see Logging), and sample() belongs to the features
deprecated by revision 2026-07-28 — on that
revision it throws, and Asking for input is the way to write it
instead.
- Talking back to the client — the
ClientGateway: asking the client's model for a completion (sampling), reporting progress on a long call, and sending notifications. - Logging — structured PSR-3 log messages that surface in the client, not in your server's log file.
- Asking for input —
ClientGateway::elicit(), or returning anInputRequiredResultwhen a handler needs several answers at once. Either way, one handler serves both protocol eras.
Handlers that need application services (a database connection, an API client) get them from the container instead; see Service dependencies.