Fix error behavior on unregistered handlers in stateless server handler#800
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maff
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Feb 16, 2026
| HttpResponse<String> response; | ||
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| HttpRequest request = HttpRequest.newBuilder() |
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ℹ️ Not using the MCP client here as it would throw a client error due to missing capabilities advertised in initialization response.
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@tzolov do you see a chance of this change making it into |
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Instead of throwing an McpError, it now returns with a JSON-RPC method not found error (-32601), aligned with the stateful implementation.
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Kehrlann
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Jun 26, 2026
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| /* | |||
| * Copyright 2024-2025 the original author or authors. | |||
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| * Copyright 2024-2025 the original author or authors. | |
| * Copyright 2026-2026 the original author or authors. |
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| response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString()); | ||
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Please use a client transport instead of raw HTTP requests.
See #1041 for inspiration
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| @ParameterizedTest | ||
| @ValueSource(strings = { "tools/list", "resources/list", "prompts/list" }) | ||
| void testMissingHandlerReturnsMethodNotFoundError(String method) throws Exception { |
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Don't do a parameterized test, instead make a request with method foo/bar or any non-existing method.
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When a client requests a resource without a registered handler despite a stateless server not advertising it, the server now returns with a JSON-RPC method not found error (-32601), aligned with the stateful implementation.
Motivation and Context
Closes issue #784
How Has This Been Tested?
Integration test covering unregistered handler response with stateless transport.
Breaking Changes
Behavioral change to return a proper JSON-RPC error instead of a HTTP 500 response. Breaking only in terms of changed behavior in case of an error.
Types of changes
Checklist
Additional context