MCP support #17

tiginamaria · 2025-05-08T16:35:23Z

MCP support:

Added McpToolRegistryProvider which instantiates mcp client (or gets as an argument), connects to it, get tools and convert to out tool format. The tool execute method calls mcp server with given args (provided in raw JsonObject as we can not build exact kotlin data class for them, see serialization)

Supported two types of connection stdio and sse, all for now in jvm module, but potentially sse can be multiplatform

EugeneTheDev

Overall looks nice, there are a few things I would like to discuss before merging: working with resources and tests

EugeneTheDev · 2025-05-13T13:45:57Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpTool.kt

+) : Tool<McpTool.Args, McpTool.Result>() {
+
+    companion object {
+        private val logger = LoggerFactory.create("ai.grazie.code.agents.mcp.McpTool")


EugeneTheDev · 2025-05-13T13:55:49Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpTool.kt

+                is JsonDecoder -> {
+                    // Decode directly from JsonElement
+                    val jsonElement = decoder.decodeJsonElement()
+                    Args(jsonElement as JsonObject)


jsonElement.jsonObject is better

EugeneTheDev · 2025-05-13T13:56:33Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpTool.kt

+         */
+        override fun toStringDefault(): String {
+            if (promptMessageContents.isEmpty()) {
+                return "[No content]"


Maybe empty string is better?

EugeneTheDev · 2025-05-13T13:58:15Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpTool.kt

+        val result = mcpClient.callTool(
+            name = descriptor.name, arguments = args.arguments
+        )
+        return Result(result?.content ?: emptyList())


content.orEmpty() is a bit more cleaner

EugeneTheDev · 2025-05-13T13:58:48Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpToolRegistryProvider.kt

+        // Create a ToolDescriptor
+        return ToolDescriptor(
+            name = sdkTool.name,
+            description = sdkTool.description ?: "",


Again, .orEmpty()

EugeneTheDev · 2025-05-13T14:10:02Z

agents/agents-tools/src/commonMain/kotlin/ai/grazie/code/agents/core/tools/ToolDescriptors.kt

     * @property itemsType The type definition for the items within the array.
     */
    data class List(val itemsType: ToolParameterType) : ToolParameterType("ARRAY")

+    /**
+     * Represents an array type parameter.


Please fix doc comment, it represents and object, actually. But that's a good addition, we need to support objects

EugeneTheDev · 2025-05-13T14:11:23Z

...-executor-cached/src/commonMain/kotlin/ai/jetbrains/code/prompt/executor/cached/ToolUtils.kt

@@ -39,6 +35,19 @@ fun ToolDescriptor.toJSONSchema(): JsonObject {
                put("type", "array")
                put("items", toolParameterToSchema(type.itemsType))
            }
+
+            is ToolParameterType.Object -> {


Seems like this whole function is not used anywhere, can we just drop it?

EugeneTheDev · 2025-05-13T14:12:14Z

...nMain/kotlin/ai/jetbrains/code/prompt/executor/clients/anthropic/AnthropicDirectLLMClient.kt

@@ -441,6 +441,20 @@ open class AnthropicDirectLLMClient(
                    "items" to getTypeMapForParameter(type.itemsType)
                )
            )
+
+            is ToolParameterType.Object -> JsonObject(


Just to confirm, did you test that all providers support these nested types (objects) in their tool api?

EugeneTheDev · 2025-05-13T14:12:58Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpToolRegistryProvider.kt

+ * 3. Transforming MCP tools into the agent framework's Tool interface
+ * 4. Registering the transformed tools in a ToolRegistry
+ */
+class McpToolRegistryProvider {


Also, I think we need tests for it, if it's possible

EugeneTheDev · 2025-05-13T14:13:39Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpTool.kt

+ * 2. Calling the MCP tool through the MCP client
+ * 3. Converting MCP tool results back to agent framework tool results
+ */
+class McpTool(


I think it would be nice to add test for it too, if It's possible

Rizzen · 2025-05-13T15:08:51Z

I see that we're supporting using the mcp tools, but currently not supporting the agent being mcp server? Do we plan it/want it at all?

Rizzen · 2025-05-13T15:01:46Z

agents/agents-mcp/src/jvmMain/kotlin/ai/grazie/code/agents/mcp/McpToolRegistryProvider.kt

+     * @param element The JSON object representing the parameter type.
+     * @return The corresponding ToolParameterType, or null if the type cannot be parsed.
+     */
+    private fun parseParameterType(element: JsonObject): ToolParameterType? {


I would move all the parsing into the separate class, just in case we (or our users) would want to change parsing logic

I also thought about somethign like this, but I'm not sure if this is the real case, since MCP format is kinda fixed, no? But giving more flexibility is still a good think, so I agree that we can think in this direction too

I mean it's just rule of thumb, MCP for now is fixed, but world is changing and we're not safe from MCPv2 someday

Yes, good points, as I already wrote, giving more flexibility and providing some sane default implementation can be nice

Created a separate parser interface with default implementation, where I moved this logic McpToolDescriptorParser

Rizzen · 2025-05-13T15:04:07Z

examples/src/main/kotlin/ai/grazie/code/agents/example/mcp/PlaywrightMcpClient.kt

+    // Get the API key from environment variables
+    val openAIApiToken = System.getenv("OPEN_AI_TOKEN")
+
+    // Start the Docker container with the Google Maps MCP server


It's Playwright

Rizzen · 2025-05-13T15:08:07Z

examples/src/main/kotlin/ai/grazie/code/agents/example/mcp/PlaywrightMcpClient.kt

+    ).start()
+
+    // Wait for the server to start
+    Thread.sleep(2000)


Well, it's not very robust, because app start time heavily varies on user's machine and we could improve it here, for example waiting to socket to be open, but it's optional for now

Since this is just in examples, let's leave it like this for now. We can add more complex logic later

Rizzen · 2025-05-13T15:10:50Z

...ain/kotlin/ai/jetbrains/code/prompt/executor/clients/openrouter/OpenRouterDirectLLMClient.kt

+            is ToolParameterType.Object -> {
+                put("type", JsonPrimitive("object"))
+                put("properties", buildJsonObject {
+                    type.properties.forEach { property ->
+                        put(property.name, buildJsonObject {
+                            fillOpenRouterParamType(property.type)
+                            put("description", property.description)
+                        })
+                    }
+                }
+                )


I suggest to move string literals to consts, here and all over OpenRouterDirectLLMClient

Let's address this in a separate PR

EugeneTheDev

We've improved API and added tests. Seems like in the current state we can merge it and work on additional features in the separate PRs

…c to default implementation

tiginamaria force-pushed the tigina/mcp-support branch from 1978c25 to 18a05fb Compare May 12, 2025 09:37

tiginamaria requested review from Ololoshechkin and sdubov May 12, 2025 11:04

tiginamaria marked this pull request as ready for review May 12, 2025 11:11

tiginamaria requested review from Rizzen and EugeneTheDev May 13, 2025 07:54

EugeneTheDev requested changes May 13, 2025

View reviewed changes

tiginamaria force-pushed the tigina/mcp-support branch from c0fdc58 to 84bf27a Compare May 13, 2025 14:28

Rizzen requested changes May 13, 2025

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EugeneTheDev approved these changes May 13, 2025

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EugeneTheDev force-pushed the tigina/mcp-support branch from bcb3e66 to 3e4ad38 Compare May 13, 2025 20:49

tiginamaria and others added 17 commits May 14, 2025 11:09

MCP module setup

59fa9d3

Struggling with parsers

24c07b8

First working version without an object as a tool type

c19b00f

Add object parameter type support

2792f44

Refactor after rebase

81df02c

Trying to add sse client

7097b7e

Add comments and refactorings

5fb6948

Fix object tool parameter type after rebase

d9b616c

Rebase

9f3f7f6

[agents/mcp] add fromTransport and default clients

ea785d0

[agents/mcp] remove nulls, throw exceptions

675896c

[agents/mcp] add McpToolTest

90f484b

[agents/mcp] add McpToolDefinitionParser interface, move parsing logi…

ab8638d

…c to default implementation

[agents/mcp] add parser test

68cffae

[agents/examples] fix mcp examples

deada35

[agents/mcp] add timeout to test, clean up deps

f4cf664

rebase fixes

93827a3

EugeneTheDev force-pushed the tigina/mcp-support branch from c8ab66e to 93827a3 Compare May 14, 2025 09:23

Rizzen approved these changes May 14, 2025

View reviewed changes

EugeneTheDev merged commit cee6611 into main May 14, 2025
3 checks passed

tiginamaria deleted the tigina/mcp-support branch May 21, 2025 16:09

MCP support #17

MCP support #17

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tiginamaria commented May 8, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Rizzen commented May 13, 2025

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tiginamaria commented May 8, 2025 •

edited

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