feat(client): add client tool output schema validation and caching (#302)

- Add JSON schema validation for tool call results against output schemas
- Implement automatic tool output schema caching during initialization
- Add `enableCallToolSchemaCaching` configuration option to enable/disable
  schema caching
- Add `JsonSchemaValidator` integration to McpClient builder APIs
- Introduce post-initialization hook mechanism for performing operations
  after successful client initialization
- Cache tool output schemas during `listTools` operations when caching
  is enabled
- Validate tool results against cached schemas in `callTool` operations
- Return error CallToolResult when validation fails
- Add test coverage
- Convert validateToolResult from Mono to synchronous method
- Throw IllegalArgumentException on validation errors

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

Co-authored-by: Anurag Pant <pantanurag555@github>
Co-authored-by: Christian Tzolov <christian.tzolov@broadcom.com>
Co-authored-by: Daniel Garnier-Moiroux <git@garnier.wf>
Co-authored-by: Dariusz Jędrzejczyk <dariusz.jedrzejczyk@broadcom.com>
This commit is contained in:
Anurag Pant 2025-09-21 20:12:32 -07:00 • committed by Christian Tzolov
commit 8e11fa82ae
10 changed files with 708 additions and 131 deletions

View file

@ -11,14 +11,13 @@ import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import io.modelcontextprotocol.spec.McpClientSession;
import io.modelcontextprotocol.spec.McpError;
import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.McpTransportSessionNotFoundException;
import io.modelcontextprotocol.util.Assert;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;
import reactor.core.publisher.Sinks;
import reactor.util.context.ContextView;
@ -99,21 +98,30 @@ class LifecycleInitializer {
*/
private final Duration initializationTimeout;
/**
* Post-initialization hook to perform additional operations after every successful
* initialization.
*/
private final Function<Initialization, Mono<Void>> postInitializationHook;
public LifecycleInitializer(McpSchema.ClientCapabilities clientCapabilities, McpSchema.Implementation clientInfo,
List<String> protocolVersions, Duration initializationTimeout,
Function<ContextView, McpClientSession> sessionSupplier) {
Function<ContextView, McpClientSession> sessionSupplier,
Function<Initialization, Mono<Void>> postInitializationHook) {
Assert.notNull(sessionSupplier, "Session supplier must not be null");
Assert.notNull(clientCapabilities, "Client capabilities must not be null");
Assert.notNull(clientInfo, "Client info must not be null");
Assert.notEmpty(protocolVersions, "Protocol versions must not be empty");
Assert.notNull(initializationTimeout, "Initialization timeout must not be null");
Assert.notNull(postInitializationHook, "Post-initialization hook must not be null");
this.sessionSupplier = sessionSupplier;
this.clientCapabilities = clientCapabilities;
this.clientInfo = clientInfo;
this.protocolVersions = Collections.unmodifiableList(new ArrayList<>(protocolVersions));
this.initializationTimeout = initializationTimeout;
this.postInitializationHook = postInitializationHook;
}
/**
@ -148,10 +156,6 @@ class LifecycleInitializer {
}
/**
* Default implementation of the {@link Initialization} interface that manages the MCP
* client initialization process.
*/
private static class DefaultInitialization implements Initialization {
/**
@ -199,29 +203,20 @@ class LifecycleInitializer {
this.mcpClientSession.set(mcpClientSession);
}
/**
* Returns a Mono that completes when the MCP client initialization is complete.
* This allows subscribers to wait for the initialization to finish before
* proceeding with further operations.
* @return A Mono that emits the result of the MCP initialization process
*/
private Mono<McpSchema.InitializeResult> await() {
return this.initSink.asMono();
}
/**
* Completes the initialization process with the given result. It caches the
* result and emits it to all subscribers waiting for the initialization to
* complete.
* @param initializeResult The result of the MCP initialization process
*/
private void complete(McpSchema.InitializeResult initializeResult) {
// first ensure the result is cached
this.result.set(initializeResult);
// inform all the subscribers waiting for the initialization
this.initSink.emitValue(initializeResult, Sinks.EmitFailureHandler.FAIL_FAST);
}
private void cacheResult(McpSchema.InitializeResult initializeResult) {
// first ensure the result is cached
this.result.set(initializeResult);
}
private void error(Throwable t) {
this.initSink.emitError(t, Sinks.EmitFailureHandler.FAIL_FAST);
}
@ -263,7 +258,7 @@ class LifecycleInitializer {
}
// Providing an empty operation since we are only interested in triggering
// the implicit initialization step.
withIntitialization("re-initializing", result -> Mono.empty()).subscribe();
this.withInitialization("re-initializing", result -> Mono.empty()).subscribe();
}
}
@ -275,7 +270,7 @@ class LifecycleInitializer {
* @param operation The operation to execute when the client is initialized
* @return A Mono that completes with the result of the operation
*/
public <T> Mono<T> withIntitialization(String actionName, Function<Initialization, Mono<T>> operation) {
public <T> Mono<T> withInitialization(String actionName, Function<Initialization, Mono<T>> operation) {
return Mono.deferContextual(ctx -> {
DefaultInitialization newInit = new DefaultInitialization();
DefaultInitialization previous = this.initializationRef.compareAndExchange(null, newInit);
@ -283,8 +278,8 @@ class LifecycleInitializer {
boolean needsToInitialize = previous == null;
logger.debug(needsToInitialize ? "Initialization process started" : "Joining previous initialization");
Mono<McpSchema.InitializeResult> initializationJob = needsToInitialize ? doInitialize(newInit, ctx)
: previous.await();
Mono<McpSchema.InitializeResult> initializationJob = needsToInitialize
? this.doInitialize(newInit, this.postInitializationHook, ctx) : previous.await();
return initializationJob.map(initializeResult -> this.initializationRef.get())
.timeout(this.initializationTimeout)
@ -296,7 +291,9 @@ class LifecycleInitializer {
});
}
private Mono<McpSchema.InitializeResult> doInitialize(DefaultInitialization initialization, ContextView ctx) {
private Mono<McpSchema.InitializeResult> doInitialize(DefaultInitialization initialization,
Function<Initialization, Mono<Void>> postInitOperation, ContextView ctx) {
initialization.setMcpClientSession(this.sessionSupplier.apply(ctx));
McpClientSession mcpClientSession = initialization.mcpSession();
@ -323,6 +320,9 @@ class LifecycleInitializer {
return mcpClientSession.sendNotification(McpSchema.METHOD_NOTIFICATION_INITIALIZED, null)
.thenReturn(initializeResult);
}).flatMap(initializeResult -> {
initialization.cacheResult(initializeResult);
return postInitOperation.apply(initialization).thenReturn(initializeResult);
}).doOnNext(initialization::complete).onErrorResume(ex -> {
initialization.error(ex);
return Mono.error(ex);

View file

@ -15,12 +15,12 @@ import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import io.modelcontextprotocol.client.LifecycleInitializer.Initialization;
import io.modelcontextprotocol.json.TypeRef;
import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
import io.modelcontextprotocol.spec.McpClientSession;
import io.modelcontextprotocol.spec.McpClientSession.NotificationHandler;
import io.modelcontextprotocol.spec.McpClientSession.RequestHandler;
import io.modelcontextprotocol.spec.McpClientTransport;
import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.McpSchema.ClientCapabilities;
@ -35,10 +35,10 @@ import io.modelcontextprotocol.spec.McpSchema.LoggingLevel;
import io.modelcontextprotocol.spec.McpSchema.LoggingMessageNotification;
import io.modelcontextprotocol.spec.McpSchema.PaginatedRequest;
import io.modelcontextprotocol.spec.McpSchema.Root;
import io.modelcontextprotocol.spec.McpClientSession.NotificationHandler;
import io.modelcontextprotocol.spec.McpClientSession.RequestHandler;
import io.modelcontextprotocol.util.Assert;
import io.modelcontextprotocol.util.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
@ -75,6 +75,7 @@ import reactor.core.publisher.Mono;
* @author Dariusz Jędrzejczyk
* @author Christian Tzolov
* @author Jihoon Kim
* @author Anurag Pant
* @see McpClient
* @see McpSchema
* @see McpClientSession
@ -152,16 +153,33 @@ public class McpAsyncClient {
*/
private final LifecycleInitializer initializer;
/**
* JSON schema validator to use for validating tool responses against output schemas.
*/
private final JsonSchemaValidator jsonSchemaValidator;
/**
* Cached tool output schemas.
*/
private final ConcurrentHashMap<String, Map<String, Object>> toolsOutputSchemaCache;
/**
* Whether to enable automatic schema caching during callTool operations.
*/
private final boolean enableCallToolSchemaCaching;
/**
* Create a new McpAsyncClient with the given transport and session request-response
* timeout.
* @param transport the transport to use.
* @param requestTimeout the session request-response timeout.
* @param initializationTimeout the max timeout to await for the client-server
* @param features the MCP Client supported features.
* @param jsonSchemaValidator the JSON schema validator to use for validating tool
* @param features the MCP Client supported features. responses against output
* schemas.
*/
McpAsyncClient(McpClientTransport transport, Duration requestTimeout, Duration initializationTimeout,
McpClientFeatures.Async features) {
JsonSchemaValidator jsonSchemaValidator, McpClientFeatures.Async features) {
Assert.notNull(transport, "Transport must not be null");
Assert.notNull(requestTimeout, "Request timeout must not be null");
@ -171,6 +189,9 @@ public class McpAsyncClient {
this.clientCapabilities = features.clientCapabilities();
this.transport = transport;
this.roots = new ConcurrentHashMap<>(features.roots());
this.jsonSchemaValidator = jsonSchemaValidator;
this.toolsOutputSchemaCache = new ConcurrentHashMap<>();
this.enableCallToolSchemaCaching = features.enableCallToolSchemaCaching();
// Request Handlers
Map<String, RequestHandler<?>> requestHandlers = new HashMap<>();
@ -273,9 +294,30 @@ public class McpAsyncClient {
notificationHandlers.put(McpSchema.METHOD_NOTIFICATION_PROGRESS,
asyncProgressNotificationHandler(progressConsumersFinal));
Function<Initialization, Mono<Void>> postInitializationHook = init -> {
if (init.initializeResult().capabilities().tools() == null || !enableCallToolSchemaCaching) {
return Mono.empty();
}
return this.listToolsInternal(init, McpSchema.FIRST_PAGE).doOnNext(listToolsResult -> {
listToolsResult.tools()
.forEach(tool -> logger.debug("Tool {} schema: {}", tool.name(), tool.outputSchema()));
if (enableCallToolSchemaCaching && listToolsResult.tools() != null) {
// Cache tools output schema
listToolsResult.tools()
.stream()
.filter(tool -> tool.outputSchema() != null)
.forEach(tool -> this.toolsOutputSchemaCache.put(tool.name(), tool.outputSchema()));
}
}).then();
};
this.initializer = new LifecycleInitializer(clientCapabilities, clientInfo, transport.protocolVersions(),
initializationTimeout, ctx -> new McpClientSession(requestTimeout, transport, requestHandlers,
notificationHandlers, con -> con.contextWrite(ctx)));
notificationHandlers, con -> con.contextWrite(ctx)),
postInitializationHook);
this.transport.setExceptionHandler(this.initializer::handleException);
}
@ -387,7 +429,7 @@ public class McpAsyncClient {
* </p>
*/
public Mono<McpSchema.InitializeResult> initialize() {
return this.initializer.withIntitialization("by explicit API call", init -> Mono.just(init.initializeResult()));
return this.initializer.withInitialization("by explicit API call", init -> Mono.just(init.initializeResult()));
}
// --------------------------
@ -399,7 +441,7 @@ public class McpAsyncClient {
* @return A Mono that completes with the server's ping response
*/
public Mono<Object> ping() {
return this.initializer.withIntitialization("pinging the server",
return this.initializer.withInitialization("pinging the server",
init -> init.mcpSession().sendRequest(McpSchema.METHOD_PING, null, OBJECT_TYPE_REF));
}
@ -480,7 +522,7 @@ public class McpAsyncClient {
* @return A Mono that completes when the notification is sent.
*/
public Mono<Void> rootsListChangedNotification() {
return this.initializer.withIntitialization("sending roots list changed notification",
return this.initializer.withInitialization("sending roots list changed notification",
init -> init.mcpSession().sendNotification(McpSchema.METHOD_NOTIFICATION_ROOTS_LIST_CHANGED));
}
@ -539,15 +581,45 @@ public class McpAsyncClient {
* @see #listTools()
*/
public Mono<McpSchema.CallToolResult> callTool(McpSchema.CallToolRequest callToolRequest) {
return this.initializer.withIntitialization("calling tools", init -> {
return this.initializer.withInitialization("calling tool", init -> {
if (init.initializeResult().capabilities().tools() == null) {
return Mono.error(new IllegalStateException("Server does not provide tools capability"));
}
return init.mcpSession()
.sendRequest(McpSchema.METHOD_TOOLS_CALL, callToolRequest, CALL_TOOL_RESULT_TYPE_REF);
.sendRequest(McpSchema.METHOD_TOOLS_CALL, callToolRequest, CALL_TOOL_RESULT_TYPE_REF)
.flatMap(result -> Mono.just(validateToolResult(callToolRequest.name(), result)));
});
}
private McpSchema.CallToolResult validateToolResult(String toolName, McpSchema.CallToolResult result) {
if (!this.enableCallToolSchemaCaching || result == null || result.isError() == Boolean.TRUE) {
// if tool schema caching is disabled or tool call resulted in an error - skip
// validation and return the result as it is
return result;
}
Map<String, Object> optOutputSchema = this.toolsOutputSchemaCache.get(toolName);
if (optOutputSchema == null) {
logger.warn(
"Calling a tool with no outputSchema is not expected to return result with structured content, but got: {}",
result.structuredContent());
return result;
}
// Validate the tool output against the cached output schema
var validation = this.jsonSchemaValidator.validate(optOutputSchema, result.structuredContent());
if (!validation.valid()) {
logger.warn("Tool call result validation failed: {}", validation.errorMessage());
throw new IllegalArgumentException("Tool call result validation failed: " + validation.errorMessage());
}
return result;
}
/**
* Retrieves the list of all tools provided by the server.
* @return A Mono that emits the list of all tools result
@ -568,14 +640,26 @@ public class McpAsyncClient {
* @return A Mono that emits the list of tools result
*/
public Mono<McpSchema.ListToolsResult> listTools(String cursor) {
return this.initializer.withIntitialization("listing tools", init -> {
if (init.initializeResult().capabilities().tools() == null) {
return Mono.error(new IllegalStateException("Server does not provide tools capability"));
}
return init.mcpSession()
.sendRequest(McpSchema.METHOD_TOOLS_LIST, new McpSchema.PaginatedRequest(cursor),
LIST_TOOLS_RESULT_TYPE_REF);
});
return this.initializer.withInitialization("listing tools", init -> this.listToolsInternal(init, cursor));
}
private Mono<McpSchema.ListToolsResult> listToolsInternal(Initialization init, String cursor) {
if (init.initializeResult().capabilities().tools() == null) {
return Mono.error(new IllegalStateException("Server does not provide tools capability"));
}
return init.mcpSession()
.sendRequest(McpSchema.METHOD_TOOLS_LIST, new McpSchema.PaginatedRequest(cursor),
LIST_TOOLS_RESULT_TYPE_REF)
.doOnNext(result -> {
if (this.enableCallToolSchemaCaching && result.tools() != null) {
// Cache tools output schema
result.tools()
.stream()
.filter(tool -> tool.outputSchema() != null)
.forEach(tool -> this.toolsOutputSchemaCache.put(tool.name(), tool.outputSchema()));
}
});
}
private NotificationHandler asyncToolsChangeNotificationHandler(
@ -632,7 +716,7 @@ public class McpAsyncClient {
* @see #readResource(McpSchema.Resource)
*/
public Mono<McpSchema.ListResourcesResult> listResources(String cursor) {
return this.initializer.withIntitialization("listing resources", init -> {
return this.initializer.withInitialization("listing resources", init -> {
if (init.initializeResult().capabilities().resources() == null) {
return Mono.error(new IllegalStateException("Server does not provide the resources capability"));
}
@ -664,7 +748,7 @@ public class McpAsyncClient {
* @see McpSchema.ReadResourceResult
*/
public Mono<McpSchema.ReadResourceResult> readResource(McpSchema.ReadResourceRequest readResourceRequest) {
return this.initializer.withIntitialization("reading resources", init -> {
return this.initializer.withInitialization("reading resources", init -> {
if (init.initializeResult().capabilities().resources() == null) {
return Mono.error(new IllegalStateException("Server does not provide the resources capability"));
}
@ -702,7 +786,7 @@ public class McpAsyncClient {
* @see McpSchema.ListResourceTemplatesResult
*/
public Mono<McpSchema.ListResourceTemplatesResult> listResourceTemplates(String cursor) {
return this.initializer.withIntitialization("listing resource templates", init -> {
return this.initializer.withInitialization("listing resource templates", init -> {
if (init.initializeResult().capabilities().resources() == null) {
return Mono.error(new IllegalStateException("Server does not provide the resources capability"));
}
@ -722,7 +806,7 @@ public class McpAsyncClient {
* @see #unsubscribeResource(McpSchema.UnsubscribeRequest)
*/
public Mono<Void> subscribeResource(McpSchema.SubscribeRequest subscribeRequest) {
return this.initializer.withIntitialization("subscribing to resources", init -> init.mcpSession()
return this.initializer.withInitialization("subscribing to resources", init -> init.mcpSession()
.sendRequest(McpSchema.METHOD_RESOURCES_SUBSCRIBE, subscribeRequest, VOID_TYPE_REFERENCE));
}
@ -736,7 +820,7 @@ public class McpAsyncClient {
* @see #subscribeResource(McpSchema.SubscribeRequest)
*/
public Mono<Void> unsubscribeResource(McpSchema.UnsubscribeRequest unsubscribeRequest) {
return this.initializer.withIntitialization("unsubscribing from resources", init -> init.mcpSession()
return this.initializer.withInitialization("unsubscribing from resources", init -> init.mcpSession()
.sendRequest(McpSchema.METHOD_RESOURCES_UNSUBSCRIBE, unsubscribeRequest, VOID_TYPE_REFERENCE));
}
@ -802,7 +886,7 @@ public class McpAsyncClient {
* @see #getPrompt(GetPromptRequest)
*/
public Mono<ListPromptsResult> listPrompts(String cursor) {
return this.initializer.withIntitialization("listing prompts", init -> init.mcpSession()
return this.initializer.withInitialization("listing prompts", init -> init.mcpSession()
.sendRequest(McpSchema.METHOD_PROMPT_LIST, new PaginatedRequest(cursor), LIST_PROMPTS_RESULT_TYPE_REF));
}
@ -816,7 +900,7 @@ public class McpAsyncClient {
* @see #listPrompts()
*/
public Mono<GetPromptResult> getPrompt(GetPromptRequest getPromptRequest) {
return this.initializer.withIntitialization("getting prompts", init -> init.mcpSession()
return this.initializer.withInitialization("getting prompts", init -> init.mcpSession()
.sendRequest(McpSchema.METHOD_PROMPT_GET, getPromptRequest, GET_PROMPT_RESULT_TYPE_REF));
}
@ -834,14 +918,6 @@ public class McpAsyncClient {
// --------------------------
// Logging
// --------------------------
/**
* Create a notification handler for logging notifications from the server. This
* handler automatically distributes logging messages to all registered consumers.
* @param loggingConsumers List of consumers that will be notified when a logging
* message is received. Each consumer receives the logging message notification.
* @return A NotificationHandler that processes log notifications by distributing the
* message to all registered consumers
*/
private NotificationHandler asyncLoggingNotificationHandler(
List<Function<LoggingMessageNotification, Mono<Void>>> loggingConsumers) {
@ -867,7 +943,7 @@ public class McpAsyncClient {
return Mono.error(new IllegalArgumentException("Logging level must not be null"));
}
return this.initializer.withIntitialization("setting logging level", init -> {
return this.initializer.withInitialization("setting logging level", init -> {
if (init.initializeResult().capabilities().logging() == null) {
return Mono.error(new IllegalStateException("Server's Logging capabilities are not enabled!"));
}
@ -876,15 +952,6 @@ public class McpAsyncClient {
});
}
/**
* Create a notification handler for progress notifications from the server. This
* handler automatically distributes progress notifications to all registered
* consumers.
* @param progressConsumers List of consumers that will be notified when a progress
* message is received. Each consumer receives the progress notification.
* @return A NotificationHandler that processes progress notifications by distributing
* the message to all registered consumers
*/
private NotificationHandler asyncProgressNotificationHandler(
List<Function<McpSchema.ProgressNotification, Mono<Void>>> progressConsumers) {
@ -924,7 +991,7 @@ public class McpAsyncClient {
* @see McpSchema.CompleteResult
*/
public Mono<McpSchema.CompleteResult> completeCompletion(McpSchema.CompleteRequest completeRequest) {
return this.initializer.withIntitialization("complete completions", init -> init.mcpSession()
return this.initializer.withInitialization("complete completions", init -> init.mcpSession()
.sendRequest(McpSchema.METHOD_COMPLETION_COMPLETE, completeRequest, COMPLETION_COMPLETE_RESULT_TYPE_REF));
}

View file

@ -13,6 +13,7 @@ import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
import io.modelcontextprotocol.common.McpTransportContext;
import io.modelcontextprotocol.spec.McpClientTransport;
import io.modelcontextprotocol.spec.McpSchema;
@ -99,6 +100,7 @@ import reactor.core.publisher.Mono;
*
* @author Christian Tzolov
* @author Dariusz Jędrzejczyk
* @author Anurag Pant
* @see McpAsyncClient
* @see McpSyncClient
* @see McpTransport
@ -187,6 +189,10 @@ public interface McpClient {
private Supplier<McpTransportContext> contextProvider = () -> McpTransportContext.EMPTY;
private JsonSchemaValidator jsonSchemaValidator;
private boolean enableCallToolSchemaCaching = false; // Default to false
private SyncSpec(McpClientTransport transport) {
Assert.notNull(transport, "Transport must not be null");
this.transport = transport;
@ -429,6 +435,32 @@ public interface McpClient {
return this;
}
/**
* Add a {@link JsonSchemaValidator} to validate the JSON structure of the
* structured output.
* @param jsonSchemaValidator A validator to validate the JSON structure of the
* structured output. Must not be null.
* @return This builder for method chaining
* @throws IllegalArgumentException if jsonSchemaValidator is null
*/
public SyncSpec jsonSchemaValidator(JsonSchemaValidator jsonSchemaValidator) {
Assert.notNull(jsonSchemaValidator, "JsonSchemaValidator must not be null");
this.jsonSchemaValidator = jsonSchemaValidator;
return this;
}
/**
* Enables automatic schema caching during callTool operations. When a tool's
* output schema is not found in the cache, callTool will automatically fetch and
* cache all tool schemas via listTools.
* @param enableCallToolSchemaCaching true to enable, false to disable
* @return This builder instance for method chaining
*/
public SyncSpec enableCallToolSchemaCaching(boolean enableCallToolSchemaCaching) {
this.enableCallToolSchemaCaching = enableCallToolSchemaCaching;
return this;
}
/**
* Create an instance of {@link McpSyncClient} with the provided configurations or
* sensible defaults.
@ -438,13 +470,13 @@ public interface McpClient {
McpClientFeatures.Sync syncFeatures = new McpClientFeatures.Sync(this.clientInfo, this.capabilities,
this.roots, this.toolsChangeConsumers, this.resourcesChangeConsumers, this.resourcesUpdateConsumers,
this.promptsChangeConsumers, this.loggingConsumers, this.progressConsumers, this.samplingHandler,
this.elicitationHandler);
this.elicitationHandler, this.enableCallToolSchemaCaching);
McpClientFeatures.Async asyncFeatures = McpClientFeatures.Async.fromSync(syncFeatures);
return new McpSyncClient(
new McpAsyncClient(transport, this.requestTimeout, this.initializationTimeout, asyncFeatures),
this.contextProvider);
return new McpSyncClient(new McpAsyncClient(transport, this.requestTimeout, this.initializationTimeout,
jsonSchemaValidator != null ? jsonSchemaValidator : JsonSchemaValidator.getDefault(),
asyncFeatures), this.contextProvider);
}
}
@ -495,6 +527,10 @@ public interface McpClient {
private Function<ElicitRequest, Mono<ElicitResult>> elicitationHandler;
private JsonSchemaValidator jsonSchemaValidator;
private boolean enableCallToolSchemaCaching = false; // Default to false
private AsyncSpec(McpClientTransport transport) {
Assert.notNull(transport, "Transport must not be null");
this.transport = transport;
@ -741,17 +777,45 @@ public interface McpClient {
return this;
}
/**
* Sets the JSON schema validator to use for validating tool responses against
* output schemas.
* @param jsonSchemaValidator The validator to use. Must not be null.
* @return This builder instance for method chaining
* @throws IllegalArgumentException if jsonSchemaValidator is null
*/
public AsyncSpec jsonSchemaValidator(JsonSchemaValidator jsonSchemaValidator) {
Assert.notNull(jsonSchemaValidator, "JsonSchemaValidator must not be null");
this.jsonSchemaValidator = jsonSchemaValidator;
return this;
}
/**
* Enables automatic schema caching during callTool operations. When a tool's
* output schema is not found in the cache, callTool will automatically fetch and
* cache all tool schemas via listTools.
* @param enableCallToolSchemaCaching true to enable, false to disable
* @return This builder instance for method chaining
*/
public AsyncSpec enableCallToolSchemaCaching(boolean enableCallToolSchemaCaching) {
this.enableCallToolSchemaCaching = enableCallToolSchemaCaching;
return this;
}
/**
* Create an instance of {@link McpAsyncClient} with the provided configurations
* or sensible defaults.
* @return a new instance of {@link McpAsyncClient}.
*/
public McpAsyncClient build() {
var jsonSchemaValidator = (this.jsonSchemaValidator != null) ? this.jsonSchemaValidator
: JsonSchemaValidator.getDefault();
return new McpAsyncClient(this.transport, this.requestTimeout, this.initializationTimeout,
jsonSchemaValidator,
new McpClientFeatures.Async(this.clientInfo, this.capabilities, this.roots,
this.toolsChangeConsumers, this.resourcesChangeConsumers, this.resourcesUpdateConsumers,
this.promptsChangeConsumers, this.loggingConsumers, this.progressConsumers,
this.samplingHandler, this.elicitationHandler));
this.samplingHandler, this.elicitationHandler, this.enableCallToolSchemaCaching));
}
}

View file

@ -62,6 +62,7 @@ class McpClientFeatures {
* @param progressConsumers the progress consumers.
* @param samplingHandler the sampling handler.
* @param elicitationHandler the elicitation handler.
* @param enableCallToolSchemaCaching whether to enable call tool schema caching.
*/
record Async(McpSchema.Implementation clientInfo, McpSchema.ClientCapabilities clientCapabilities,
Map<String, McpSchema.Root> roots, List<Function<List<McpSchema.Tool>, Mono<Void>>> toolsChangeConsumers,
@ -71,7 +72,8 @@ class McpClientFeatures {
List<Function<McpSchema.LoggingMessageNotification, Mono<Void>>> loggingConsumers,
List<Function<McpSchema.ProgressNotification, Mono<Void>>> progressConsumers,
Function<McpSchema.CreateMessageRequest, Mono<McpSchema.CreateMessageResult>> samplingHandler,
Function<McpSchema.ElicitRequest, Mono<McpSchema.ElicitResult>> elicitationHandler) {
Function<McpSchema.ElicitRequest, Mono<McpSchema.ElicitResult>> elicitationHandler,
boolean enableCallToolSchemaCaching) {
/**
* Create an instance and validate the arguments.
@ -84,6 +86,7 @@ class McpClientFeatures {
* @param progressConsumers the progress consumers.
* @param samplingHandler the sampling handler.
* @param elicitationHandler the elicitation handler.
* @param enableCallToolSchemaCaching whether to enable call tool schema caching.
*/
public Async(McpSchema.Implementation clientInfo, McpSchema.ClientCapabilities clientCapabilities,
Map<String, McpSchema.Root> roots,
@ -94,7 +97,8 @@ class McpClientFeatures {
List<Function<McpSchema.LoggingMessageNotification, Mono<Void>>> loggingConsumers,
List<Function<McpSchema.ProgressNotification, Mono<Void>>> progressConsumers,
Function<McpSchema.CreateMessageRequest, Mono<McpSchema.CreateMessageResult>> samplingHandler,
Function<McpSchema.ElicitRequest, Mono<McpSchema.ElicitResult>> elicitationHandler) {
Function<McpSchema.ElicitRequest, Mono<McpSchema.ElicitResult>> elicitationHandler,
boolean enableCallToolSchemaCaching) {
Assert.notNull(clientInfo, "Client info must not be null");
this.clientInfo = clientInfo;
@ -113,6 +117,7 @@ class McpClientFeatures {
this.progressConsumers = progressConsumers != null ? progressConsumers : List.of();
this.samplingHandler = samplingHandler;
this.elicitationHandler = elicitationHandler;
this.enableCallToolSchemaCaching = enableCallToolSchemaCaching;
}
/**
@ -129,7 +134,7 @@ class McpClientFeatures {
Function<McpSchema.ElicitRequest, Mono<McpSchema.ElicitResult>> elicitationHandler) {
this(clientInfo, clientCapabilities, roots, toolsChangeConsumers, resourcesChangeConsumers,
resourcesUpdateConsumers, promptsChangeConsumers, loggingConsumers, List.of(), samplingHandler,
elicitationHandler);
elicitationHandler, false);
}
/**
@ -187,7 +192,8 @@ class McpClientFeatures {
return new Async(syncSpec.clientInfo(), syncSpec.clientCapabilities(), syncSpec.roots(),
toolsChangeConsumers, resourcesChangeConsumers, resourcesUpdateConsumers, promptsChangeConsumers,
loggingConsumers, progressConsumers, samplingHandler, elicitationHandler);
loggingConsumers, progressConsumers, samplingHandler, elicitationHandler,
syncSpec.enableCallToolSchemaCaching);
}
}
@ -205,6 +211,7 @@ class McpClientFeatures {
* @param progressConsumers the progress consumers.
* @param samplingHandler the sampling handler.
* @param elicitationHandler the elicitation handler.
* @param enableCallToolSchemaCaching whether to enable call tool schema caching.
*/
public record Sync(McpSchema.Implementation clientInfo, McpSchema.ClientCapabilities clientCapabilities,
Map<String, McpSchema.Root> roots, List<Consumer<List<McpSchema.Tool>>> toolsChangeConsumers,
@ -214,7 +221,8 @@ class McpClientFeatures {
List<Consumer<McpSchema.LoggingMessageNotification>> loggingConsumers,
List<Consumer<McpSchema.ProgressNotification>> progressConsumers,
Function<McpSchema.CreateMessageRequest, McpSchema.CreateMessageResult> samplingHandler,
Function<McpSchema.ElicitRequest, McpSchema.ElicitResult> elicitationHandler) {
Function<McpSchema.ElicitRequest, McpSchema.ElicitResult> elicitationHandler,
boolean enableCallToolSchemaCaching) {
/**
* Create an instance and validate the arguments.
@ -229,6 +237,7 @@ class McpClientFeatures {
* @param progressConsumers the progress consumers.
* @param samplingHandler the sampling handler.
* @param elicitationHandler the elicitation handler.
* @param enableCallToolSchemaCaching whether to enable call tool schema caching.
*/
public Sync(McpSchema.Implementation clientInfo, McpSchema.ClientCapabilities clientCapabilities,
Map<String, McpSchema.Root> roots, List<Consumer<List<McpSchema.Tool>>> toolsChangeConsumers,
@ -238,7 +247,8 @@ class McpClientFeatures {
List<Consumer<McpSchema.LoggingMessageNotification>> loggingConsumers,
List<Consumer<McpSchema.ProgressNotification>> progressConsumers,
Function<McpSchema.CreateMessageRequest, McpSchema.CreateMessageResult> samplingHandler,
Function<McpSchema.ElicitRequest, McpSchema.ElicitResult> elicitationHandler) {
Function<McpSchema.ElicitRequest, McpSchema.ElicitResult> elicitationHandler,
boolean enableCallToolSchemaCaching) {
Assert.notNull(clientInfo, "Client info must not be null");
this.clientInfo = clientInfo;
@ -257,6 +267,7 @@ class McpClientFeatures {
this.progressConsumers = progressConsumers != null ? progressConsumers : List.of();
this.samplingHandler = samplingHandler;
this.elicitationHandler = elicitationHandler;
this.enableCallToolSchemaCaching = enableCallToolSchemaCaching;
}
/**
@ -272,7 +283,7 @@ class McpClientFeatures {
Function<McpSchema.ElicitRequest, McpSchema.ElicitResult> elicitationHandler) {
this(clientInfo, clientCapabilities, roots, toolsChangeConsumers, resourcesChangeConsumers,
resourcesUpdateConsumers, promptsChangeConsumers, loggingConsumers, List.of(), samplingHandler,
elicitationHandler);
elicitationHandler, false);
}
}

View file

@ -17,7 +17,6 @@ import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
import io.modelcontextprotocol.json.McpJsonMapper;
import io.modelcontextprotocol.json.TypeRef;
import io.modelcontextprotocol.util.Assert;

View file

@ -4,15 +4,14 @@
package io.modelcontextprotocol.client;
import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
import io.modelcontextprotocol.spec.McpClientTransport;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Timeout;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.containers.wait.strategy.Wait;
import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
import io.modelcontextprotocol.spec.McpClientTransport;
@Timeout(15)
public class HttpClientStreamableHttpAsyncClientTests extends AbstractMcpAsyncClientTests {

View file

@ -0,0 +1,280 @@
/*
* Copyright 2024-2024 the original author or authors.
*/
package io.modelcontextprotocol.client;
import java.time.Duration;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
import io.modelcontextprotocol.client.LifecycleInitializer.Initialization;
import io.modelcontextprotocol.spec.McpClientSession;
import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.McpTransportSessionNotFoundException;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import reactor.core.publisher.Mono;
import reactor.core.scheduler.Schedulers;
import reactor.test.StepVerifier;
import reactor.util.context.ContextView;
import static org.assertj.core.api.Assertions.assertThat;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
/**
* Tests for {@link LifecycleInitializer} postInitializationHook functionality.
*
* @author Christian Tzolov
*/
class LifecycleInitializerPostInitializationHookTests {
private static final Duration INITIALIZATION_TIMEOUT = Duration.ofSeconds(5);
private static final McpSchema.ClientCapabilities CLIENT_CAPABILITIES = McpSchema.ClientCapabilities.builder()
.build();
private static final McpSchema.Implementation CLIENT_INFO = new McpSchema.Implementation("test-client", "1.0.0");
private static final List<String> PROTOCOL_VERSIONS = List.of("1.0.0", "2.0.0");
private static final McpSchema.InitializeResult MOCK_INIT_RESULT = new McpSchema.InitializeResult("2.0.0",
McpSchema.ServerCapabilities.builder().build(), new McpSchema.Implementation("test-server", "1.0.0"),
"Test instructions");
@Mock
private McpClientSession mockClientSession;
@Mock
private Function<ContextView, McpClientSession> mockSessionSupplier;
@Mock
private Function<Initialization, Mono<Void>> mockPostInitializationHook;
private LifecycleInitializer initializer;
@BeforeEach
void setUp() {
MockitoAnnotations.openMocks(this);
when(mockPostInitializationHook.apply(any(Initialization.class))).thenReturn(Mono.empty());
when(mockSessionSupplier.apply(any(ContextView.class))).thenReturn(mockClientSession);
when(mockClientSession.sendRequest(eq(McpSchema.METHOD_INITIALIZE), any(), any()))
.thenReturn(Mono.just(MOCK_INIT_RESULT));
when(mockClientSession.sendNotification(eq(McpSchema.METHOD_NOTIFICATION_INITIALIZED), any()))
.thenReturn(Mono.empty());
when(mockClientSession.closeGracefully()).thenReturn(Mono.empty());
initializer = new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO, PROTOCOL_VERSIONS,
INITIALIZATION_TIMEOUT, mockSessionSupplier, mockPostInitializationHook);
}
@Test
void shouldInvokePostInitializationHook() {
AtomicReference<Initialization> capturedInit = new AtomicReference<>();
when(mockPostInitializationHook.apply(any(Initialization.class))).thenAnswer(invocation -> {
capturedInit.set(invocation.getArgument(0));
return Mono.empty();
});
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
// Verify hook was called
verify(mockPostInitializationHook, times(1)).apply(any(Initialization.class));
// Verify the hook received correct initialization data
assertThat(capturedInit.get()).isNotNull();
assertThat(capturedInit.get().mcpSession()).isEqualTo(mockClientSession);
assertThat(capturedInit.get().initializeResult()).isEqualTo(MOCK_INIT_RESULT);
}
@Test
void shouldInvokePostInitializationHookOnlyOnce() {
// First initialization
StepVerifier.create(initializer.withInitialization("test1", init -> Mono.just("result1")))
.expectNext("result1")
.verifyComplete();
// Second call should reuse initialization and NOT call hook again
StepVerifier.create(initializer.withInitialization("test2", init -> Mono.just("result2")))
.expectNext("result2")
.verifyComplete();
// Hook should only be called once
verify(mockPostInitializationHook, times(1)).apply(any(Initialization.class));
}
@Test
void shouldInvokePostInitializationHookOnlyOnceWithConcurrentRequests() {
AtomicInteger hookInvocationCount = new AtomicInteger(0);
when(mockPostInitializationHook.apply(any(Initialization.class))).thenAnswer(invocation -> {
hookInvocationCount.incrementAndGet();
return Mono.empty();
});
// Start multiple concurrent initializations
Mono<String> init1 = initializer.withInitialization("test1", init -> Mono.just("result1"))
.subscribeOn(Schedulers.parallel());
Mono<String> init2 = initializer.withInitialization("test2", init -> Mono.just("result2"))
.subscribeOn(Schedulers.parallel());
Mono<String> init3 = initializer.withInitialization("test3", init -> Mono.just("result3"))
.subscribeOn(Schedulers.parallel());
// TODO: can we assume the order of results?
StepVerifier.create(Mono.zip(init1, init2, init3)).assertNext(tuple -> {
assertThat(tuple.getT1()).isEqualTo("result1");
assertThat(tuple.getT2()).isEqualTo("result2");
assertThat(tuple.getT3()).isEqualTo("result3");
}).verifyComplete();
// Hook should only be called once despite concurrent requests
assertThat(hookInvocationCount.get()).isEqualTo(1);
}
@Test
void shouldFailInitializationWhenPostInitializationHookFails() {
RuntimeException hookError = new RuntimeException("Post-initialization hook failed");
when(mockPostInitializationHook.apply(any(Initialization.class))).thenReturn(Mono.error(hookError));
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectErrorMatches(ex -> ex instanceof RuntimeException && ex.getCause() == hookError)
.verify();
// Verify initialization was not completed
assertThat(initializer.isInitialized()).isFalse();
assertThat(initializer.currentInitializationResult()).isNull();
// Verify the hook was called
verify(mockPostInitializationHook, times(1)).apply(any(Initialization.class));
}
@Test
void shouldNotInvokePostInitializationHookWhenInitializationFails() {
when(mockClientSession.sendRequest(eq(McpSchema.METHOD_INITIALIZE), any(), any()))
.thenReturn(Mono.error(new RuntimeException("Initialization failed")));
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectError(RuntimeException.class)
.verify();
// Hook should NOT be called when initialization fails
verify(mockPostInitializationHook, never()).apply(any(Initialization.class));
}
@Test
void shouldNotInvokePostInitializationHookWhenNotificationFails() {
when(mockClientSession.sendNotification(eq(McpSchema.METHOD_NOTIFICATION_INITIALIZED), any()))
.thenReturn(Mono.error(new RuntimeException("Notification failed")));
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectError(RuntimeException.class)
.verify();
// Hook should NOT be called when notification fails
verify(mockPostInitializationHook, never()).apply(any(Initialization.class));
}
@Test
void shouldInvokePostInitializationHookAgainAfterReinitialization() {
AtomicInteger hookInvocationCount = new AtomicInteger(0);
when(mockPostInitializationHook.apply(any(Initialization.class))).thenAnswer(invocation -> {
hookInvocationCount.incrementAndGet();
return Mono.empty();
});
// First initialization
StepVerifier.create(initializer.withInitialization("test1", init -> Mono.just("result1")))
.expectNext("result1")
.verifyComplete();
assertThat(hookInvocationCount.get()).isEqualTo(1);
// Simulate transport session exception to trigger re-initialization
initializer.handleException(new McpTransportSessionNotFoundException("Session lost"));
// Hook should be called twice (once for each initialization)
assertThat(hookInvocationCount.get()).isEqualTo(2);
}
@Test
void shouldAllowPostInitializationHookToPerformAsyncOperations() {
AtomicInteger operationCount = new AtomicInteger(0);
when(mockPostInitializationHook.apply(any(Initialization.class)))
.thenReturn(Mono.fromRunnable(() -> operationCount.incrementAndGet()).then());
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
// Verify the async operation was executed
assertThat(operationCount.get()).isEqualTo(1);
verify(mockPostInitializationHook, times(1)).apply(any(Initialization.class));
}
@Test
void shouldProvideCorrectInitializationDataToHook() {
AtomicReference<McpClientSession> capturedSession = new AtomicReference<>();
AtomicReference<McpSchema.InitializeResult> capturedResult = new AtomicReference<>();
when(mockPostInitializationHook.apply(any(Initialization.class))).thenAnswer(invocation -> {
Initialization init = invocation.getArgument(0);
capturedSession.set(init.mcpSession());
capturedResult.set(init.initializeResult());
return Mono.empty();
});
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
// Verify the hook received the correct session and result
assertThat(capturedSession.get()).isEqualTo(mockClientSession);
assertThat(capturedResult.get()).isEqualTo(MOCK_INIT_RESULT);
assertThat(capturedResult.get().protocolVersion()).isEqualTo("2.0.0");
assertThat(capturedResult.get().serverInfo().name()).isEqualTo("test-server");
}
@Test
void shouldInvokePostInitializationHookAfterSuccessfulInitialization() {
AtomicReference<Boolean> notificationSent = new AtomicReference<>(false);
AtomicReference<Boolean> hookCalledAfterNotification = new AtomicReference<>(false);
when(mockClientSession.sendNotification(eq(McpSchema.METHOD_NOTIFICATION_INITIALIZED), any()))
.thenAnswer(invocation -> {
notificationSent.set(true);
return Mono.empty();
});
when(mockPostInitializationHook.apply(any(Initialization.class))).thenAnswer(invocation -> {
// Due to flatMap chaining in doInitialize, if the hook is called,
// the notification must have been sent first
hookCalledAfterNotification.set(notificationSent.get());
return Mono.empty();
});
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
// Verify the hook was called and notification was already sent at that point
assertThat(hookCalledAfterNotification.get()).isTrue();
verify(mockClientSession).sendNotification(eq(McpSchema.METHOD_NOTIFICATION_INITIALIZED), any());
verify(mockPostInitializationHook).apply(any(Initialization.class));
}
}

View file

@ -10,14 +10,14 @@ import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
import io.modelcontextprotocol.client.LifecycleInitializer.Initialization;
import io.modelcontextprotocol.spec.McpClientSession;
import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.McpTransportSessionNotFoundException;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import io.modelcontextprotocol.spec.McpClientSession;
import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.McpTransportSessionNotFoundException;
import reactor.core.publisher.Mono;
import reactor.core.scheduler.Schedulers;
import reactor.test.StepVerifier;
@ -58,12 +58,16 @@ class LifecycleInitializerTests {
@Mock
private Function<ContextView, McpClientSession> mockSessionSupplier;
@Mock
private Function<Initialization, Mono<Void>> mockPostInitializationHook;
private LifecycleInitializer initializer;
@BeforeEach
void setUp() {
MockitoAnnotations.openMocks(this);
when(mockPostInitializationHook.apply(any(Initialization.class))).thenReturn(Mono.empty());
when(mockSessionSupplier.apply(any(ContextView.class))).thenReturn(mockClientSession);
when(mockClientSession.sendRequest(eq(McpSchema.METHOD_INITIALIZE), any(), any()))
.thenReturn(Mono.just(MOCK_INIT_RESULT));
@ -72,45 +76,45 @@ class LifecycleInitializerTests {
when(mockClientSession.closeGracefully()).thenReturn(Mono.empty());
initializer = new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO, PROTOCOL_VERSIONS,
INITIALIZATION_TIMEOUT, mockSessionSupplier);
INITIALIZATION_TIMEOUT, mockSessionSupplier, mockPostInitializationHook);
}
@Test
void constructorShouldValidateParameters() {
assertThatThrownBy(() -> new LifecycleInitializer(null, CLIENT_INFO, PROTOCOL_VERSIONS, INITIALIZATION_TIMEOUT,
mockSessionSupplier))
mockSessionSupplier, mockPostInitializationHook))
.isInstanceOf(IllegalArgumentException.class)
.hasMessageContaining("Client capabilities must not be null");
assertThatThrownBy(() -> new LifecycleInitializer(CLIENT_CAPABILITIES, null, PROTOCOL_VERSIONS,
INITIALIZATION_TIMEOUT, mockSessionSupplier))
INITIALIZATION_TIMEOUT, mockSessionSupplier, mockPostInitializationHook))
.isInstanceOf(IllegalArgumentException.class)
.hasMessageContaining("Client info must not be null");
assertThatThrownBy(() -> new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO, null,
INITIALIZATION_TIMEOUT, mockSessionSupplier))
INITIALIZATION_TIMEOUT, mockSessionSupplier, mockPostInitializationHook))
.isInstanceOf(IllegalArgumentException.class)
.hasMessageContaining("Protocol versions must not be empty");
assertThatThrownBy(() -> new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO, List.of(),
INITIALIZATION_TIMEOUT, mockSessionSupplier))
INITIALIZATION_TIMEOUT, mockSessionSupplier, mockPostInitializationHook))
.isInstanceOf(IllegalArgumentException.class)
.hasMessageContaining("Protocol versions must not be empty");
assertThatThrownBy(() -> new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO, PROTOCOL_VERSIONS, null,
mockSessionSupplier))
mockSessionSupplier, mockPostInitializationHook))
.isInstanceOf(IllegalArgumentException.class)
.hasMessageContaining("Initialization timeout must not be null");
assertThatThrownBy(() -> new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO, PROTOCOL_VERSIONS,
INITIALIZATION_TIMEOUT, null))
INITIALIZATION_TIMEOUT, null, mockPostInitializationHook))
.isInstanceOf(IllegalArgumentException.class)
.hasMessageContaining("Session supplier must not be null");
}
@Test
void shouldInitializeSuccessfully() {
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.assertNext(result -> {
assertThat(result).isEqualTo(MOCK_INIT_RESULT);
assertThat(initializer.isInitialized()).isTrue();
@ -132,7 +136,7 @@ class LifecycleInitializerTests {
return Mono.just(MOCK_INIT_RESULT);
});
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.assertNext(result -> {
assertThat(capturedRequest.get().protocolVersion()).isEqualTo("2.0.0"); // Latest
// version
@ -152,7 +156,7 @@ class LifecycleInitializerTests {
when(mockClientSession.sendRequest(eq(McpSchema.METHOD_INITIALIZE), any(), any()))
.thenReturn(Mono.just(unsupportedResult));
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectError(RuntimeException.class)
.verify();
@ -167,13 +171,13 @@ class LifecycleInitializerTests {
Duration SLOW_RESPONSE_DELAY = Duration.ofSeconds(5);
LifecycleInitializer shortTimeoutInitializer = new LifecycleInitializer(CLIENT_CAPABILITIES, CLIENT_INFO,
PROTOCOL_VERSIONS, INITIALIZE_TIMEOUT, mockSessionSupplier);
PROTOCOL_VERSIONS, INITIALIZE_TIMEOUT, mockSessionSupplier, mockPostInitializationHook);
when(mockClientSession.<McpSchema.InitializeResult>sendRequest(eq(McpSchema.METHOD_INITIALIZE), any(), any()))
.thenReturn(Mono.just(MOCK_INIT_RESULT).delayElement(SLOW_RESPONSE_DELAY, virtualTimeScheduler));
StepVerifier
.withVirtualTime(() -> shortTimeoutInitializer.withIntitialization("test",
.withVirtualTime(() -> shortTimeoutInitializer.withInitialization("test",
init -> Mono.just(init.initializeResult())), () -> virtualTimeScheduler, Long.MAX_VALUE)
.expectSubscription()
.expectNoEvent(INITIALIZE_TIMEOUT)
@ -184,12 +188,12 @@ class LifecycleInitializerTests {
@Test
void shouldReuseExistingInitialization() {
// First initialization
StepVerifier.create(initializer.withIntitialization("test1", init -> Mono.just("result1")))
StepVerifier.create(initializer.withInitialization("test1", init -> Mono.just("result1")))
.expectNext("result1")
.verifyComplete();
// Second call should reuse the same initialization
StepVerifier.create(initializer.withIntitialization("test2", init -> Mono.just("result2")))
StepVerifier.create(initializer.withInitialization("test2", init -> Mono.just("result2")))
.expectNext("result2")
.verifyComplete();
@ -209,11 +213,11 @@ class LifecycleInitializerTests {
// Start multiple concurrent initializations using subscribeOn with parallel
// scheduler
Mono<String> init1 = initializer.withIntitialization("test1", init -> Mono.just("result1"))
Mono<String> init1 = initializer.withInitialization("test1", init -> Mono.just("result1"))
.subscribeOn(Schedulers.parallel());
Mono<String> init2 = initializer.withIntitialization("test2", init -> Mono.just("result2"))
Mono<String> init2 = initializer.withInitialization("test2", init -> Mono.just("result2"))
.subscribeOn(Schedulers.parallel());
Mono<String> init3 = initializer.withIntitialization("test3", init -> Mono.just("result3"))
Mono<String> init3 = initializer.withInitialization("test3", init -> Mono.just("result3"))
.subscribeOn(Schedulers.parallel());
StepVerifier.create(Mono.zip(init1, init2, init3)).assertNext(tuple -> {
@ -235,7 +239,7 @@ class LifecycleInitializerTests {
// succeeds on the second call
.thenReturn(Mono.just(MOCK_INIT_RESULT));
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectError(RuntimeException.class)
.verify();
@ -244,7 +248,7 @@ class LifecycleInitializerTests {
// The initializer can recover from previous errors
StepVerifier
.create(initializer.withIntitialization("successful init", init -> Mono.just(init.initializeResult())))
.create(initializer.withInitialization("successful init", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
@ -255,7 +259,7 @@ class LifecycleInitializerTests {
@Test
void shouldHandleTransportSessionNotFoundException() {
// successful initialization first
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
@ -277,7 +281,7 @@ class LifecycleInitializerTests {
@Test
void shouldHandleOtherExceptions() {
// Simulate a successful initialization first
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
@ -295,7 +299,7 @@ class LifecycleInitializerTests {
@Test
void shouldCloseGracefully() {
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
@ -307,7 +311,7 @@ class LifecycleInitializerTests {
@Test
void shouldCloseImmediately() {
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
@ -342,7 +346,7 @@ class LifecycleInitializerTests {
new McpSchema.Implementation("test-server", "1.0.0"), "Test instructions"));
});
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.assertNext(result -> {
// Latest from new versions
assertThat(capturedRequest.get().protocolVersion()).isEqualTo("4.0.0");
@ -363,7 +367,7 @@ class LifecycleInitializerTests {
});
StepVerifier
.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult()))
.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult()))
.contextWrite(Context.of(contextKey, contextValue)))
.expectNext(MOCK_INIT_RESULT)
.verifyComplete();
@ -374,7 +378,7 @@ class LifecycleInitializerTests {
@Test
void shouldProvideAccessToMcpSessionAndInitializeResult() {
StepVerifier.create(initializer.withIntitialization("test", init -> {
StepVerifier.create(initializer.withInitialization("test", init -> {
assertThat(init.mcpSession()).isEqualTo(mockClientSession);
assertThat(init.initializeResult()).isEqualTo(MOCK_INIT_RESULT);
return Mono.just("success");
@ -386,7 +390,7 @@ class LifecycleInitializerTests {
when(mockClientSession.sendNotification(eq(McpSchema.METHOD_NOTIFICATION_INITIALIZED), any()))
.thenReturn(Mono.error(new RuntimeException("Notification failed")));
StepVerifier.create(initializer.withIntitialization("test", init -> Mono.just(init.initializeResult())))
StepVerifier.create(initializer.withInitialization("test", init -> Mono.just(init.initializeResult())))
.expectError(RuntimeException.class)
.verify();
@ -403,7 +407,7 @@ class LifecycleInitializerTests {
@Test
void shouldReinitializeAfterTransportSessionException() {
// First initialization
StepVerifier.create(initializer.withIntitialization("test1", init -> Mono.just("result1")))
StepVerifier.create(initializer.withInitialization("test1", init -> Mono.just("result1")))
.expectNext("result1")
.verifyComplete();
@ -411,7 +415,7 @@ class LifecycleInitializerTests {
initializer.handleException(new McpTransportSessionNotFoundException("Session lost"));
// Should be able to initialize again
StepVerifier.create(initializer.withIntitialization("test2", init -> Mono.just("result2")))
StepVerifier.create(initializer.withInitialization("test2", init -> Mono.just("result2")))
.expectNext("result2")
.verifyComplete();

View file

@ -10,12 +10,20 @@ import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.ProtocolVersions;
import org.junit.jupiter.api.Test;
import reactor.core.publisher.Mono;
import com.fasterxml.jackson.core.JsonProcessingException;
import reactor.core.publisher.Mono;
import reactor.test.StepVerifier;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
import static io.modelcontextprotocol.util.McpJsonMapperUtils.JSON_MAPPER;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatCode;
class McpAsyncClientTests {
@ -24,6 +32,7 @@ class McpAsyncClientTests {
"1.0.0");
public static final McpSchema.ServerCapabilities MOCK_SERVER_CAPABILITIES = McpSchema.ServerCapabilities.builder()
.tools(true)
.build();
public static final McpSchema.InitializeResult MOCK_INIT_RESULT = new McpSchema.InitializeResult(
@ -31,6 +40,91 @@ class McpAsyncClientTests {
private static final String CONTEXT_KEY = "context.key";
private McpClientTransport createMockTransportForToolValidation(boolean hasOutputSchema, boolean invalidOutput)
throws JsonProcessingException {
// Create tool with or without output schema
Map<String, Object> inputSchemaMap = Map.of("type", "object", "properties",
Map.of("expression", Map.of("type", "string")), "required", List.of("expression"));
McpSchema.JsonSchema inputSchema = new McpSchema.JsonSchema("object", inputSchemaMap, null, null, null, null);
McpSchema.Tool.Builder toolBuilder = McpSchema.Tool.builder()
.name("calculator")
.description("Performs mathematical calculations")
.inputSchema(inputSchema);
if (hasOutputSchema) {
Map<String, Object> outputSchema = Map.of("type", "object", "properties",
Map.of("result", Map.of("type", "number"), "operation", Map.of("type", "string")), "required",
List.of("result", "operation"));
toolBuilder.outputSchema(outputSchema);
}
McpSchema.Tool calculatorTool = toolBuilder.build();
McpSchema.ListToolsResult mockToolsResult = new McpSchema.ListToolsResult(List.of(calculatorTool), null);
// Create call tool result - valid or invalid based on parameter
Map<String, Object> structuredContent = invalidOutput ? Map.of("result", "5", "operation", "add")
: Map.of("result", 5, "operation", "add");
McpSchema.CallToolResult mockCallToolResult = McpSchema.CallToolResult.builder()
.addTextContent("Calculation result")
.structuredContent(structuredContent)
.build();
return new McpClientTransport() {
Function<Mono<McpSchema.JSONRPCMessage>, Mono<McpSchema.JSONRPCMessage>> handler;
@Override
public Mono<Void> connect(
Function<Mono<McpSchema.JSONRPCMessage>, Mono<McpSchema.JSONRPCMessage>> handler) {
this.handler = handler;
return Mono.empty();
}
@Override
public Mono<Void> closeGracefully() {
return Mono.empty();
}
@Override
public Mono<Void> sendMessage(McpSchema.JSONRPCMessage message) {
if (!(message instanceof McpSchema.JSONRPCRequest request)) {
return Mono.empty();
}
McpSchema.JSONRPCResponse response;
if (McpSchema.METHOD_INITIALIZE.equals(request.method())) {
response = new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(), MOCK_INIT_RESULT,
null);
}
else if (McpSchema.METHOD_TOOLS_LIST.equals(request.method())) {
response = new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(), mockToolsResult,
null);
}
else if (McpSchema.METHOD_TOOLS_CALL.equals(request.method())) {
response = new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(),
mockCallToolResult, null);
}
else {
return Mono.empty();
}
return handler.apply(Mono.just(response)).then();
}
@Override
public <T> T unmarshalFrom(Object data, TypeRef<T> typeRef) {
return JSON_MAPPER.convertValue(data, new TypeRef<>() {
@Override
public java.lang.reflect.Type getType() {
return typeRef.getType();
}
});
}
};
}
@Test
void validateContextPassedToTransportConnect() {
McpClientTransport transport = new McpClientTransport() {
@ -87,4 +181,64 @@ class McpAsyncClientTests {
}).doesNotThrowAnyException();
}
@Test
void testCallToolWithOutputSchemaValidationSuccess() throws JsonProcessingException {
McpClientTransport transport = createMockTransportForToolValidation(true, false);
McpAsyncClient client = McpClient.async(transport).enableCallToolSchemaCaching(true).build();
StepVerifier.create(client.initialize()).expectNextMatches(Objects::nonNull).verifyComplete();
StepVerifier.create(client.callTool(new McpSchema.CallToolRequest("calculator", Map.of("expression", "2 + 3"))))
.expectNextMatches(response -> {
assertThat(response).isNotNull();
assertThat(response.isError()).isFalse();
assertThat(response.structuredContent()).isInstanceOf(Map.class);
assertThat((Map<?, ?>) response.structuredContent()).hasSize(2);
assertThat(response.content()).hasSize(1);
return true;
})
.verifyComplete();
StepVerifier.create(client.closeGracefully()).verifyComplete();
}
@Test
void testCallToolWithNoOutputSchemaSuccess() throws JsonProcessingException {
McpClientTransport transport = createMockTransportForToolValidation(false, false);
McpAsyncClient client = McpClient.async(transport).enableCallToolSchemaCaching(true).build();
StepVerifier.create(client.initialize()).expectNextMatches(Objects::nonNull).verifyComplete();
StepVerifier.create(client.callTool(new McpSchema.CallToolRequest("calculator", Map.of("expression", "2 + 3"))))
.expectNextMatches(response -> {
assertThat(response).isNotNull();
assertThat(response.isError()).isFalse();
assertThat(response.structuredContent()).isInstanceOf(Map.class);
assertThat((Map<?, ?>) response.structuredContent()).hasSize(2);
assertThat(response.content()).hasSize(1);
return true;
})
.verifyComplete();
StepVerifier.create(client.closeGracefully()).verifyComplete();
}
@Test
void testCallToolWithOutputSchemaValidationFailure() throws JsonProcessingException {
McpClientTransport transport = createMockTransportForToolValidation(true, true);
McpAsyncClient client = McpClient.async(transport).enableCallToolSchemaCaching(true).build();
StepVerifier.create(client.initialize()).expectNextMatches(Objects::nonNull).verifyComplete();
StepVerifier.create(client.callTool(new McpSchema.CallToolRequest("calculator", Map.of("expression", "2 + 3"))))
.expectErrorMatches(ex -> ex instanceof IllegalArgumentException
&& ex.getMessage().contains("Tool call result validation failed"))
.verify();
StepVerifier.create(client.closeGracefully()).verifyComplete();
}
}

View file

@ -8,9 +8,9 @@ import java.time.Duration;
import java.util.List;
import io.modelcontextprotocol.MockMcpClientTransport;
import io.modelcontextprotocol.spec.McpError;
import io.modelcontextprotocol.spec.McpSchema;
import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
import org.junit.jupiter.api.Test;
import reactor.core.publisher.Mono;
import reactor.test.StepVerifier;
@ -22,7 +22,7 @@ import static org.assertj.core.api.Assertions.assertThat;
*/
class McpClientProtocolVersionTests {
private static final Duration REQUEST_TIMEOUT = Duration.ofSeconds(30);
private static final Duration REQUEST_TIMEOUT = Duration.ofSeconds(300);
private static final McpSchema.Implementation CLIENT_INFO = new McpSchema.Implementation("test-client", "1.0.0");
@ -46,13 +46,12 @@ class McpClientProtocolVersionTests {
assertThat(initRequest.protocolVersion()).isEqualTo(transport.protocolVersions().get(0));
transport.simulateIncomingMessage(new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(),
new McpSchema.InitializeResult(protocolVersion, null,
new McpSchema.InitializeResult(protocolVersion, ServerCapabilities.builder().build(),
new McpSchema.Implementation("test-server", "1.0.0"), null),
null));
}).assertNext(result -> {
assertThat(result.protocolVersion()).isEqualTo(protocolVersion);
}).verifyComplete();
}
finally {
// Ensure cleanup happens even if test fails
@ -81,7 +80,7 @@ class McpClientProtocolVersionTests {
assertThat(initRequest.protocolVersion()).isIn(List.of(oldVersion, McpSchema.LATEST_PROTOCOL_VERSION));
transport.simulateIncomingMessage(new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(),
new McpSchema.InitializeResult(oldVersion, null,
new McpSchema.InitializeResult(oldVersion, ServerCapabilities.builder().build(),
new McpSchema.Implementation("test-server", "1.0.0"), null),
null));
}).assertNext(result -> {
@ -110,7 +109,7 @@ class McpClientProtocolVersionTests {
assertThat(request.params()).isInstanceOf(McpSchema.InitializeRequest.class);
transport.simulateIncomingMessage(new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(),
new McpSchema.InitializeResult(unsupportedVersion, null,
new McpSchema.InitializeResult(unsupportedVersion, ServerCapabilities.builder().build(),
new McpSchema.Implementation("test-server", "1.0.0"), null),
null));
}).expectError(RuntimeException.class).verify();
@ -143,7 +142,7 @@ class McpClientProtocolVersionTests {
assertThat(initRequest.protocolVersion()).isEqualTo(latestVersion);
transport.simulateIncomingMessage(new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(),
new McpSchema.InitializeResult(latestVersion, null,
new McpSchema.InitializeResult(latestVersion, ServerCapabilities.builder().build(),
new McpSchema.Implementation("test-server", "1.0.0"), null),
null));
}).assertNext(result -> {