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fix: Remove copy/pasta 🍝 in Mcp[Aync]Tool
PiperOrigin-RevId: 795476458
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-169
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+173
-169
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‎core/src/main/java/com/google/adk/tools/mcp/AbstractMcpTool.java‎

Lines changed: 161 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,161 @@
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/*
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* Copyright 2025 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.adk.tools.mcp;
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import com.fasterxml.jackson.core.JsonProcessingException;
20+
import com.fasterxml.jackson.core.type.TypeReference;
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import com.fasterxml.jackson.databind.ObjectMapper;
22+
import com.google.adk.tools.BaseTool;
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import com.google.common.collect.ImmutableMap;
24+
import com.google.genai.types.FunctionDeclaration;
25+
import com.google.genai.types.Schema;
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import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
27+
import io.modelcontextprotocol.spec.McpSchema.Content;
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import io.modelcontextprotocol.spec.McpSchema.JsonSchema;
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import io.modelcontextprotocol.spec.McpSchema.TextContent;
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import io.modelcontextprotocol.spec.McpSchema.Tool;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Map;
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import java.util.Optional;
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/**
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* Base class for MCP tools.
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*
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* @param <T> The type of the MCP session client.
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*/
42+
public abstract class AbstractMcpTool<T> extends BaseTool {
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protected final Tool mcpTool;
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protected final McpSessionManager mcpSessionManager;
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protected final ObjectMapper objectMapper;
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// Volatile ensures write visibility in the asynchronous chain for McpAsyncTool.
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protected volatile T mcpSession;
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51+
protected AbstractMcpTool(
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Tool mcpTool, T mcpSession, McpSessionManager mcpSessionManager, ObjectMapper objectMapper) {
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super(
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mcpTool == null ? "" : mcpTool.name(),
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mcpTool == null ? "" : (mcpTool.description().isEmpty() ? "" : mcpTool.description()));
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57+
if (mcpTool == null) {
58+
throw new IllegalArgumentException("mcpTool cannot be null");
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}
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if (mcpSession == null) {
61+
throw new IllegalArgumentException("mcpSession cannot be null");
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}
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if (mcpSessionManager == null) {
64+
throw new IllegalArgumentException("mcpSessionManager cannot be null");
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}
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if (objectMapper == null) {
67+
throw new IllegalArgumentException("objectMapper cannot be null");
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}
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this.mcpTool = mcpTool;
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this.mcpSession = mcpSession;
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this.mcpSessionManager = mcpSessionManager;
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this.objectMapper = objectMapper;
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}
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public T getMcpSession() {
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return this.mcpSession;
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}
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protected Schema toGeminiSchema(JsonSchema openApiSchema) {
80+
try {
81+
return GeminiSchemaUtil.toGeminiSchema(openApiSchema, this.objectMapper);
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} catch (IOException | IllegalArgumentException e) {
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throw new IllegalArgumentException(
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"Error generating function declaration for tool '" + this.name() + "': " + e.getMessage(),
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e);
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}
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}
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@Override
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public Optional<FunctionDeclaration> declaration() {
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try {
92+
Schema schema = toGeminiSchema(this.mcpTool.inputSchema());
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return Optional.ofNullable(schema)
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.map(
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value ->
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FunctionDeclaration.builder()
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.name(this.name())
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.description(this.description())
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.parameters(value)
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.build());
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} catch (IllegalArgumentException e) {
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System.err.println(e.getMessage());
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return Optional.empty();
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}
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}
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@SuppressWarnings("PreferredInterfaceType") // BaseTool.runAsync() returns Map<String, Object>
108+
protected static Map<String, Object> wrapCallResult(
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ObjectMapper objectMapper, String mcpToolName, CallToolResult callResult) {
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if (callResult == null) {
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return ImmutableMap.of("error", "MCP framework error: CallToolResult was null");
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}
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List<Content> contents = callResult.content();
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Boolean isToolError = callResult.isError();
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if (isToolError != null && isToolError) {
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String errorMessage = "Tool execution failed.";
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if (contents != null
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&& !contents.isEmpty()
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&& contents.get(0) instanceof TextContent textContent) {
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if (textContent.text() != null && !textContent.text().isEmpty()) {
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errorMessage += " Details: " + textContent.text();
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}
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}
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return ImmutableMap.of("error", errorMessage);
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}
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if (contents == null || contents.isEmpty()) {
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return ImmutableMap.of();
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}
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List<String> textOutputs = new ArrayList<>();
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for (Content content : contents) {
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if (content instanceof TextContent textContent) {
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if (textContent.text() != null) {
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textOutputs.add(textContent.text());
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}
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}
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}
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if (textOutputs.isEmpty()) {
143+
return ImmutableMap.of(
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"error",
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"Tool '" + mcpToolName + "' returned content that is not TextContent.",
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"content_details",
147+
contents.toString());
148+
}
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List<Map<String, Object>> resultMaps = new ArrayList<>();
151+
for (String textOutput : textOutputs) {
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try {
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resultMaps.add(
154+
objectMapper.readValue(textOutput, new TypeReference<Map<String, Object>>() {}));
155+
} catch (JsonProcessingException e) {
156+
resultMaps.add(ImmutableMap.of("text", textOutput));
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}
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}
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return ImmutableMap.of("text_output", resultMaps);
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}
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}

‎core/src/main/java/com/google/adk/tools/mcp/McpAsyncTool.java‎

Lines changed: 5 additions & 52 deletions
Original file line numberDiff line numberDiff line change
@@ -20,20 +20,15 @@
2020

2121
import com.fasterxml.jackson.databind.ObjectMapper;
2222
import com.google.adk.JsonBaseModel;
23-
import com.google.adk.tools.BaseTool;
2423
import com.google.adk.tools.ToolContext;
2524
import com.google.common.collect.ImmutableMap;
26-
import com.google.genai.types.FunctionDeclaration;
27-
import com.google.genai.types.Schema;
2825
import io.modelcontextprotocol.client.McpAsyncClient;
2926
import io.modelcontextprotocol.spec.McpSchema;
3027
import io.modelcontextprotocol.spec.McpSchema.CallToolRequest;
31-
import io.modelcontextprotocol.spec.McpSchema.JsonSchema;
3228
import io.modelcontextprotocol.spec.McpSchema.Tool;
3329
import io.reactivex.rxjava3.core.Maybe;
3430
import io.reactivex.rxjava3.core.Single;
3531
import java.util.Map;
36-
import java.util.Optional;
3732
import org.slf4j.Logger;
3833
import org.slf4j.LoggerFactory;
3934

@@ -45,16 +40,10 @@
4540
* <p>This wraps a MCP Tool interface and an active MCP Session. It invokes the MCP Tool through
4641
* executing the tool from remote MCP Session.
4742
*/
48-
public final class McpAsyncTool extends BaseTool {
43+
public final class McpAsyncTool extends AbstractMcpTool<McpAsyncClient> {
4944

5045
private static final Logger logger = LoggerFactory.getLogger(McpAsyncTool.class);
5146

52-
Tool mcpTool;
53-
// Volatile ensures write visibility in the asynchronous chain.
54-
volatile McpAsyncClient mcpSession;
55-
McpSessionManager mcpSessionManager;
56-
ObjectMapper objectMapper;
57-
5847
/**
5948
* Creates a new McpAsyncTool with the default ObjectMapper.
6049
*
@@ -65,7 +54,7 @@ public final class McpAsyncTool extends BaseTool {
6554
*/
6655
public McpAsyncTool(
6756
Tool mcpTool, McpAsyncClient mcpSession, McpSessionManager mcpSessionManager) {
68-
this(mcpTool, mcpSession, mcpSessionManager, JsonBaseModel.getMapper());
57+
super(mcpTool, mcpSession, mcpSessionManager, JsonBaseModel.getMapper());
6958
}
7059

7160
/**
@@ -82,31 +71,7 @@ public McpAsyncTool(
8271
McpAsyncClient mcpSession,
8372
McpSessionManager mcpSessionManager,
8473
ObjectMapper objectMapper) {
85-
super(
86-
mcpTool == null ? "" : mcpTool.name(),
87-
mcpTool == null ? "" : (mcpTool.description().isEmpty() ? "" : mcpTool.description()));
88-
89-
if (mcpTool == null) {
90-
throw new IllegalArgumentException("mcpTool cannot be null");
91-
}
92-
if (mcpSession == null) {
93-
throw new IllegalArgumentException("mcpSession cannot be null");
94-
}
95-
if (objectMapper == null) {
96-
throw new IllegalArgumentException("objectMapper cannot be null");
97-
}
98-
this.mcpTool = mcpTool;
99-
this.mcpSession = mcpSession;
100-
this.mcpSessionManager = mcpSessionManager;
101-
this.objectMapper = objectMapper;
102-
}
103-
104-
public McpAsyncClient getMcpSession() {
105-
return this.mcpSession;
106-
}
107-
108-
public Schema toGeminiSchema(JsonSchema openApiSchema) {
109-
return Schema.fromJson(objectMapper.valueToTree(openApiSchema).toString());
74+
super(mcpTool, mcpSession, mcpSessionManager, objectMapper);
11075
}
11176

11277
private Single<McpSchema.InitializeResult> reintializeSession() {
@@ -129,16 +94,6 @@ private Single<McpSchema.InitializeResult> reintializeSession() {
12994
.toFuture());
13095
}
13196

132-
@Override
133-
public Optional<FunctionDeclaration> declaration() {
134-
return Optional.of(
135-
FunctionDeclaration.builder()
136-
.name(this.name())
137-
.description(this.description())
138-
.parameters(toGeminiSchema(this.mcpTool.inputSchema()))
139-
.build());
140-
}
141-
14297
@Override
14398
public Single<Map<String, Object>> runAsync(Map<String, Object> args, ToolContext toolContext) {
14499
return Single.defer(
@@ -147,12 +102,10 @@ public Single<Map<String, Object>> runAsync(Map<String, Object> args, ToolContex
147102
this.mcpSession
148103
.callTool(new CallToolRequest(this.name(), ImmutableMap.copyOf(args)))
149104
.toFuture())
150-
.map(
151-
callResult ->
152-
McpTool.wrapCallResult(this.objectMapper, this.name(), callResult))
105+
.map(callResult -> wrapCallResult(this.objectMapper, this.name(), callResult))
153106
.switchIfEmpty(
154107
Single.fromCallable(
155-
() -> McpTool.wrapCallResult(this.objectMapper, this.name(), null))))
108+
() -> wrapCallResult(this.objectMapper, this.name(), null))))
156109
.retryWhen(
157110
errors ->
158111
errors

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