diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java index d0476e5f2..f8733dda7 100644 --- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java +++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java @@ -1089,9 +1089,7 @@ private McpRequestHandler completionCompleteRequestHan McpServerFeatures.AsyncCompletionSpecification specification = this.completions.get(request.ref()); if (specification == null) { - return Mono.error(McpError.builder(ErrorCodes.INVALID_PARAMS) - .message("AsyncCompletionSpecification not found: " + request.ref()) - .build()); + return EMPTY_COMPLETION_RESULT; } return Mono.defer(() -> specification.completionHandler().apply(exchange, request)); diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java index 48b17ed2a..bfb0149bf 100644 --- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java +++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java @@ -813,9 +813,7 @@ private McpStatelessRequestHandler completionCompleteR McpStatelessServerFeatures.AsyncCompletionSpecification specification = this.completions.get(request.ref()); if (specification == null) { - return Mono.error(McpError.builder(ErrorCodes.INVALID_PARAMS) - .message("AsyncCompletionSpecification not found: " + request.ref()) - .build()); + return EMPTY_COMPLETION_RESULT; } return specification.completionHandler().apply(ctx, request); diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStatelessIntegrationTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStatelessIntegrationTests.java index e383d20ac..f52709ad9 100644 --- a/mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStatelessIntegrationTests.java +++ b/mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStatelessIntegrationTests.java @@ -28,6 +28,9 @@ import io.modelcontextprotocol.spec.McpSchema.Prompt; import io.modelcontextprotocol.spec.McpSchema.PromptArgument; import io.modelcontextprotocol.spec.McpSchema.PromptReference; +import io.modelcontextprotocol.spec.McpSchema.ReadResourceResult; +import io.modelcontextprotocol.spec.McpSchema.ResourceReference; +import io.modelcontextprotocol.spec.McpSchema.ResourceTemplate; import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities; import io.modelcontextprotocol.spec.McpSchema.TextContent; import io.modelcontextprotocol.spec.McpSchema.Tool; @@ -230,6 +233,110 @@ void testCompletionShouldReturnExpectedSuggestions(String clientType) { } } + @ParameterizedTest(name = "{0} : Completion call without matching handler") + @ValueSource(strings = { "httpclient" }) + void testCompletionWithoutMatchingHandlerReturnsEmptyResult(String clientType) { + var clientBuilder = clientBuilders.get(clientType); + + BiFunction completionHandler = (transportContext, + request) -> new CompleteResult(new CompleteResult.CompleteCompletion(List.of("java"), 1, false)); + + var prompt = Prompt.builder("code_review") + .title("Code review") + .description("this is code review prompt") + .arguments(List + .of(PromptArgument.builder("language").title("Language").description("string").required(false).build())) + .build(); + + var otherPrompt = Prompt.builder("other_prompt") + .title("Other prompt") + .description("this prompt has completions") + .arguments(List + .of(PromptArgument.builder("topic").title("Topic").description("string").required(false).build())) + .build(); + + var mcpServer = McpServer.sync(mcpStatelessServerTransport) + .capabilities(ServerCapabilities.builder().completions().build()) + .prompts( + new McpStatelessServerFeatures.SyncPromptSpecification(prompt, + (transportContext, getPromptRequest) -> null), + new McpStatelessServerFeatures.SyncPromptSpecification(otherPrompt, + (transportContext, getPromptRequest) -> null)) + .completions(new McpStatelessServerFeatures.SyncCompletionSpecification( + PromptReference.builder("other_prompt").title("Other prompt").build(), completionHandler)) + .build(); + + try (var mcpClient = clientBuilder.build()) { + InitializeResult initResult = mcpClient.initialize(); + assertThat(initResult).isNotNull(); + + CompleteRequest request = CompleteRequest + .builder(PromptReference.builder("code_review").title("Code review").build(), + new CompleteRequest.CompleteArgument("language", "ja")) + .build(); + + CompleteResult result = mcpClient.completeCompletion(request); + + assertThat(result.completion().values()).isEmpty(); + assertThat(result.completion().total()).isZero(); + assertThat(result.completion().hasMore()).isFalse(); + } + finally { + mcpServer.close(); + } + } + + @ParameterizedTest(name = "{0} : Resource template completion call without matching handler") + @ValueSource(strings = { "httpclient" }) + void testResourceTemplateCompletionWithoutMatchingHandlerReturnsEmptyResult(String clientType) { + var clientBuilder = clientBuilders.get(clientType); + + BiFunction completionHandler = (transportContext, + request) -> new CompleteResult(new CompleteResult.CompleteCompletion(List.of("java"), 1, false)); + + var template = ResourceTemplate.builder("test://resource/{param}", "Test Resource") + .title("Test resource") + .description("A resource template for testing") + .mimeType("text/plain") + .build(); + + var otherTemplate = ResourceTemplate.builder("test://other/{param}", "Other Resource") + .title("Other resource") + .description("A resource template with completions") + .mimeType("text/plain") + .build(); + + var mcpServer = McpServer.sync(mcpStatelessServerTransport) + .capabilities(ServerCapabilities.builder().completions().build()) + .resourceTemplates( + new McpStatelessServerFeatures.SyncResourceTemplateSpecification(template, + (transportContext, req) -> ReadResourceResult.builder(List.of()).build()), + new McpStatelessServerFeatures.SyncResourceTemplateSpecification(otherTemplate, + (transportContext, req) -> ReadResourceResult.builder(List.of()).build())) + .completions(new McpStatelessServerFeatures.SyncCompletionSpecification( + new ResourceReference("test://other/{param}"), completionHandler)) + .build(); + + try (var mcpClient = clientBuilder.build()) { + InitializeResult initResult = mcpClient.initialize(); + assertThat(initResult).isNotNull(); + + CompleteRequest request = CompleteRequest + .builder(new ResourceReference("test://resource/{param}"), + new CompleteRequest.CompleteArgument("param", "ja")) + .build(); + + CompleteResult result = mcpClient.completeCompletion(request); + + assertThat(result.completion().values()).isEmpty(); + assertThat(result.completion().total()).isZero(); + assertThat(result.completion().hasMore()).isFalse(); + } + finally { + mcpServer.close(); + } + } + // --------------------------------------- // Tool Structured Output Schema Tests // --------------------------------------- diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/server/McpCompletionTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/server/McpCompletionTests.java index 710a55447..9a68318dc 100644 --- a/mcp-test/src/test/java/io/modelcontextprotocol/server/McpCompletionTests.java +++ b/mcp-test/src/test/java/io/modelcontextprotocol/server/McpCompletionTests.java @@ -31,6 +31,7 @@ import io.modelcontextprotocol.spec.McpSchema.ReadResourceResult; import io.modelcontextprotocol.spec.McpSchema.Resource; import io.modelcontextprotocol.spec.McpSchema.ResourceReference; +import io.modelcontextprotocol.spec.McpSchema.ResourceTemplate; import io.modelcontextprotocol.spec.McpSchema.PromptReference; import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities; import io.modelcontextprotocol.spec.McpError; @@ -179,6 +180,99 @@ void testCompletionBackwardCompatibility() { mcpServer.close(); } + @Test + void testCompletionWithoutMatchingHandlerReturnsEmptyResult() { + BiFunction completionHandler = (exchange, + request) -> new CompleteResult(new CompleteResult.CompleteCompletion(List.of("java"), 1, false)); + + McpSchema.Prompt prompt = Prompt.builder("code_review") + .description("this is a code review prompt") + .arguments(List.of(PromptArgument.builder("language").description("string").required(false).build())) + .build(); + + McpSchema.Prompt otherPrompt = Prompt.builder("other_prompt") + .description("this prompt has completions") + .arguments(List.of(PromptArgument.builder("topic").description("string").required(false).build())) + .build(); + + var mcpServer = McpServer.sync(mcpServerTransportProvider) + .capabilities(ServerCapabilities.builder().completions().build()) + .prompts( + new McpServerFeatures.SyncPromptSpecification(prompt, + (mcpSyncServerExchange, getPromptRequest) -> null), + new McpServerFeatures.SyncPromptSpecification(otherPrompt, + (mcpSyncServerExchange, getPromptRequest) -> null)) + .completions(new McpServerFeatures.SyncCompletionSpecification(new PromptReference("other_prompt"), + completionHandler)) + .build(); + + try (var mcpClient = clientBuilder + .clientInfo(McpSchema.Implementation.builder("Sample " + "client", "0.0.0").build()) + .build();) { + InitializeResult initResult = mcpClient.initialize(); + assertThat(initResult).isNotNull(); + + CompleteRequest request = CompleteRequest + .builder(new PromptReference("code_review"), new CompleteRequest.CompleteArgument("language", "ja")) + .build(); + + CompleteResult result = mcpClient.completeCompletion(request); + + assertThat(result.completion().values()).isEmpty(); + assertThat(result.completion().total()).isZero(); + assertThat(result.completion().hasMore()).isFalse(); + } + + mcpServer.close(); + } + + @Test + void testResourceTemplateCompletionWithoutMatchingHandlerReturnsEmptyResult() { + BiFunction completionHandler = (exchange, + request) -> new CompleteResult(new CompleteResult.CompleteCompletion(List.of("java"), 1, false)); + + ResourceTemplate template = ResourceTemplate.builder("test://resource/{param}", "Test Resource") + .description("A resource template for testing") + .mimeType("text/plain") + .build(); + + ResourceTemplate otherTemplate = ResourceTemplate.builder("test://other/{param}", "Other Resource") + .description("A resource template with completions") + .mimeType("text/plain") + .build(); + + var mcpServer = McpServer.sync(mcpServerTransportProvider) + .capabilities(ServerCapabilities.builder().completions().build()) + .resourceTemplates( + new McpServerFeatures.SyncResourceTemplateSpecification(template, + (exchange, req) -> ReadResourceResult.builder(List.of()).build()), + new McpServerFeatures.SyncResourceTemplateSpecification(otherTemplate, + (exchange, req) -> ReadResourceResult.builder(List.of()).build())) + .completions(new McpServerFeatures.SyncCompletionSpecification( + new ResourceReference("test://other/{param}"), completionHandler)) + .build(); + + try (var mcpClient = clientBuilder + .clientInfo(McpSchema.Implementation.builder("Sample " + "client", "0.0.0").build()) + .build();) { + InitializeResult initResult = mcpClient.initialize(); + assertThat(initResult).isNotNull(); + + CompleteRequest request = CompleteRequest + .builder(new ResourceReference("test://resource/{param}"), + new CompleteRequest.CompleteArgument("param", "ja")) + .build(); + + CompleteResult result = mcpClient.completeCompletion(request); + + assertThat(result.completion().values()).isEmpty(); + assertThat(result.completion().total()).isZero(); + assertThat(result.completion().hasMore()).isFalse(); + } + + mcpServer.close(); + } + @Test void testDependentCompletionScenario() { BiFunction completionHandler = (exchange, request) -> { @@ -365,4 +459,4 @@ void testPromptWithoutArgumentsCompletionForArgument() { mcpServer.close(); } -} \ No newline at end of file +}