Skip to content

Fix: Preserve McpError semantics when prompt methods are invoked via reflection #95

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
vinsguru wants to merge 1 commit into
base: main
Choose a base branch
from
Open

Fix: Preserve McpError semantics when prompt methods are invoked via reflection #95

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 5 additions & 1 deletion ...ns/src/main/java/org/springaicommunity/mcp/method/prompt/SyncMcpPromptMethodCallback.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@

package org.springaicommunity.mcp.method.prompt;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;
import java.util.function.BiFunction;
Expand Down Expand Up @@ -107,7 +108,10 @@ public GetPromptResult apply(McpSyncServerExchange exchange, GetPromptRequest re
return promptResult;
}
catch (Exception e) {
if (e instanceof McpError mcpError && mcpError.getJsonRpcError() != null) {

Throwable cause = e instanceof InvocationTargetException ite ? ite.getTargetException() : e;

if (cause instanceof McpError mcpError && mcpError.getJsonRpcError() != null) {
throw mcpError;
}

Expand Down
29 changes: 23 additions & 6 deletions ...c/test/java/org/springaicommunity/mcp/method/prompt/SyncMcpPromptMethodCallbackTests.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
import java.util.Map;
import java.util.function.BiFunction;

import io.modelcontextprotocol.spec.McpSchema;
import org.junit.jupiter.api.Test;
import org.springaicommunity.mcp.annotation.McpArg;
import org.springaicommunity.mcp.annotation.McpMeta;
Expand Down Expand Up @@ -44,7 +45,10 @@ private static class TestPromptProvider {

@McpPrompt(name = "failing-prompt", description = "A prompt that throws an exception")
public GetPromptResult getFailingPrompt(GetPromptRequest request) {
throw new RuntimeException("Test exception");
if (request.arguments().get("type").toString().equals("runTimeException")) {
throw new RuntimeException("Test exception");
}
throw McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR).message("Internal error").build();
}

@McpPrompt(name = "greeting", description = "A simple greeting prompt")
Expand Down Expand Up @@ -215,14 +219,27 @@ public void testMethodInvocationError() throws Exception {
.build();

McpSyncServerExchange exchange = mock(McpSyncServerExchange.class);
Map<String, Object> args = new HashMap<>();
args.put("name", "John");
GetPromptRequest request = new GetPromptRequest("failing-prompt", args);
GetPromptRequest runTimeExceptionRequest = new GetPromptRequest("failing-prompt",
Map.of("type", "runTimeException"));

// The new error handling should throw McpError instead of
// McpPromptMethodException
assertThatThrownBy(() -> callback.apply(exchange, request)).isInstanceOf(McpError.class)
.hasMessageContaining("Error invoking prompt method");
assertThatThrownBy(() -> callback.apply(exchange, runTimeExceptionRequest)).isInstanceOf(McpError.class)
.satisfies(t -> {
McpError e = (McpError) t;
assertThat(e.getJsonRpcError().code()).isEqualTo(McpSchema.ErrorCodes.INVALID_PARAMS);
assertThat(e.getJsonRpcError().message()).contains("Error invoking prompt method");
});

// McpError should be preserved
GetPromptRequest mcpErrorRequest = new GetPromptRequest("failing-prompt", Map.of("type", "mcpError"));

assertThatThrownBy(() -> callback.apply(exchange, mcpErrorRequest)).isInstanceOf(McpError.class)
.satisfies(t -> {
McpError e = (McpError) t;
assertThat(e.getJsonRpcError().code()).isEqualTo(McpSchema.ErrorCodes.INTERNAL_ERROR);
assertThat(e.getJsonRpcError().message()).isEqualTo("Internal error");
});
}

@Test
Expand Down