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Merged
tvallin merged 10 commits into from
Mar 6, 2026
Merged

Refactor API to be consistent #150

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2396f0e
Introduces new API
tvallin Feb 24, 2026
5eb0187
Refactor Sampling to align with API design
tvallin Feb 26, 2026
6d9968c
Make completion result total optional
tvallin Mar 2, 2026
c977810
review fixes
tvallin Mar 3, 2026
9419ad5
remove unused import in example
tvallin Mar 3, 2026
6a2a432
Review fixes
tvallin Mar 3, 2026
a0c8490
Make "hasMore" optional + update resource uri to URI
tvallin Mar 4, 2026
9491bbf
Update completion javadoc + decorator to ensure proper suggestion size
tvallin Mar 4, 2026
3729f0c
Separate MCP components interface from their configuration
tvallin Mar 4, 2026
eb09e79
Use mediaType instead of mimeType to be consistent between content types
tvallin Mar 5, 2026
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4 changes: 2 additions & 2 deletions codegen/src/main/java/io/helidon/extensions/mcp/codegen/McpCodegen.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2025 Oracle and/or its affiliates.
* Copyright (c) 2025, 2026 Oracle and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -61,7 +61,7 @@ final class McpCodegen implements CodegenExtension {
McpCodegen(CodegenContext context) {
logger = context.logger();
recorder = new McpRecorder();
toolCodegen = new McpToolCodegen(recorder);
toolCodegen = new McpToolCodegen(recorder, context);
promptCodegen = new McpPromptCodegen(recorder);
resourceCodegen = new McpResourceCodegen(recorder);
completionCodegen = new McpCompletionCodegen(recorder);
Expand Down
44 changes: 42 additions & 2 deletions codegen/src/main/java/io/helidon/extensions/mcp/codegen/McpCodegenUtil.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2025 Oracle and/or its affiliates.
* Copyright (c) 2025, 2026 Oracle and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -21,6 +21,7 @@
import java.util.stream.Collectors;

import io.helidon.codegen.classmodel.ClassModel;
import io.helidon.codegen.classmodel.Executable;
import io.helidon.codegen.classmodel.Method;
import io.helidon.codegen.classmodel.Parameter;
import io.helidon.common.types.AccessModifier;
Expand All @@ -34,19 +35,28 @@

import static io.helidon.common.types.TypeNames.LIST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_CANCELLATION;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_DESCRIPTION;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_FEATURES;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_LOGGER;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PARAMETERS;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROGRESS;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_RESOURCE_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_ROOTS;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_SAMPLING;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_SUBSCRIBE_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_TOOL_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_UNSUBSCRIBE_REQUEST;

/**
* Utility class for methods used by several MCP code generator.
*/
class McpCodegenUtil {
/**
* Pattern to match the first character of a string.
*/
private static final Pattern PATTERN = Pattern.compile("^.");

static final List<String> MCP_TYPES = List.of(MCP_REQUEST.classNameWithEnclosingNames(),
Expand Down Expand Up @@ -119,7 +129,12 @@ static boolean isIgnoredSchemaElement(TypeName typeName) {
|| MCP_FEATURES.equals(typeName)
|| MCP_PROGRESS.equals(typeName)
|| MCP_SAMPLING.equals(typeName)
|| MCP_CANCELLATION.equals(typeName);
|| MCP_PARAMETERS.equals(typeName)
|| MCP_CANCELLATION.equals(typeName)
|| MCP_TOOL_REQUEST.equals(typeName)
|| MCP_PROMPT_REQUEST.equals(typeName)
|| MCP_RESOURCE_REQUEST.equals(typeName)
|| MCP_COMPLETION_REQUEST.equals(typeName);
}

static boolean isResourceTemplate(String uri) {
Expand Down Expand Up @@ -154,6 +169,23 @@ static void addToListMethod(ClassModel.Builder classModel, TypeName type) {
classModel.addMethod(method.build());
}

/**
* Add text content to the builder as literal. The text can be multi line.
*
* @param builder executable builder
* @param text text content
*/
static void generateSafeMultiLine(Executable.Builder<?, ?> builder, String text) {
if (text.contains("\n")) {
builder.addContentLine("\"\"\"")
.increaseContentPadding()
.addContent(text.replace("\\\"", "\""))
.addContent("\"\"\"");
} else {
builder.addContentLiteral(text);
}
}

/**
* Returns {@code true} if the provided type is an MCP type and create request getter for that type,
* otherwise nothing is created and return {@code false}.
Expand Down Expand Up @@ -195,6 +227,14 @@ static boolean isMcpType(List<String> parameters, TypedElementInfo type) {
parameters.add("request.parameters()");
return true;
}
if (MCP_UNSUBSCRIBE_REQUEST.equals(type.typeName())) {
parameters.add("request");
return true;
}
if (MCP_SUBSCRIBE_REQUEST.equals(type.typeName())) {
parameters.add("request");
return true;
}
return false;
}

Expand Down
34 changes: 18 additions & 16 deletions codegen/src/main/java/io/helidon/extensions/mcp/codegen/McpCompletionCodegen.java
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Original file line number Diff line number Diff line change
Expand Up @@ -34,12 +34,11 @@
import static io.helidon.extensions.mcp.codegen.McpCodegenUtil.createClassName;
import static io.helidon.extensions.mcp.codegen.McpCodegenUtil.getElementsWithAnnotation;
import static io.helidon.extensions.mcp.codegen.McpCodegenUtil.isMcpType;
import static io.helidon.extensions.mcp.codegen.McpTypes.FUNCTION_COMPLETION_REQUEST_COMPLETION_CONTENT;
import static io.helidon.extensions.mcp.codegen.McpTypes.LIST_STRING;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_CONTENT;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_CONTENTS;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_INTERFACE;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_RESULT;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_COMPLETION_TYPE;

class McpCompletionCodegen {
Expand Down Expand Up @@ -92,14 +91,18 @@ private void addCompletionMethod(Method.Builder builder, ClassModel.Builder clas
List<String> parameters = new ArrayList<>();

builder.name("completion")
.returnType(returned -> returned.type(FUNCTION_COMPLETION_REQUEST_COMPLETION_CONTENT))
.returnType(returned -> returned.type(MCP_COMPLETION_RESULT))
.addParameter(parameter -> parameter.type(MCP_COMPLETION_REQUEST).name("request"))
.addAnnotation(Annotations.OVERRIDE);
builder.addContentLine("return request -> {");

for (TypedElementInfo parameter : element.parameterArguments()) {
if (isMcpType(parameters, parameter)) {
continue;
}
if (parameter.typeName().equals(MCP_COMPLETION_REQUEST)) {
parameters.add("request");
continue;
}
if (parameter.typeName().equals(TypeNames.STRING)) {
parameters.add(parameter.elementName());
builder.addContent("var ")
Expand All @@ -114,31 +117,30 @@ private void addCompletionMethod(Method.Builder builder, ClassModel.Builder clas

String params = String.join(", ", parameters);
if (element.typeName().equals(LIST_STRING)) {
builder.addContent("return ")
.addContent(MCP_COMPLETION_CONTENTS)
.addContent(".completion(delegate.")
// Create local variable for delegate result called "list".
builder.addContent(LIST_STRING)
.addContent(" list = delegate.")
.addContent(element.elementName())
.addContent("(")
.addContent(params)
.addContentLine("));")
.decreaseContentPadding()
.addContentLine("};");
.addContentLine(");");
builder.addContent("return ")
.addContent(MCP_COMPLETION_RESULT)
.addContentLine(".create(list);");
return;
}
if (element.typeName().equals(MCP_COMPLETION_CONTENT)) {
if (element.typeName().equals(MCP_COMPLETION_RESULT)) {
builder.addContent("return delegate.")
.addContent(element.elementName())
.addContent("(")
.addContent(params)
.addContentLine(");")
.decreaseContentPadding()
.addContentLine("};");
.addContentLine(");");
return;
}
throw new CodegenException(String.format("Wrong return type for method: %s. Supported types are: %s, or %s.",
element.elementName(),
LIST_STRING,
MCP_COMPLETION_CONTENT.classNameWithTypes()));
MCP_COMPLETION_RESULT.classNameWithTypes()));

}
}
59 changes: 30 additions & 29 deletions codegen/src/main/java/io/helidon/extensions/mcp/codegen/McpPromptCodegen.java
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2025 Oracle and/or its affiliates.
* Copyright (c) 2025, 2026 Oracle and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -17,7 +17,6 @@

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

import io.helidon.codegen.CodegenException;
import io.helidon.codegen.classmodel.ClassModel;
Expand All @@ -35,15 +34,14 @@
import static io.helidon.extensions.mcp.codegen.McpCodegenUtil.getElementsWithAnnotation;
import static io.helidon.extensions.mcp.codegen.McpCodegenUtil.isIgnoredSchemaElement;
import static io.helidon.extensions.mcp.codegen.McpCodegenUtil.isMcpType;
import static io.helidon.extensions.mcp.codegen.McpTypes.FUNCTION_REQUEST_LIST_PROMPT_CONTENT;
import static io.helidon.extensions.mcp.codegen.McpTypes.LIST_MCP_PROMPT_ARGUMENT;
import static io.helidon.extensions.mcp.codegen.McpTypes.LIST_MCP_PROMPT_CONTENT;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_DESCRIPTION;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_NAME;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT_ARGUMENT;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT_CONTENTS;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT_INTERFACE;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT_REQUEST;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_PROMPT_RESULT;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_ROLE;
import static io.helidon.extensions.mcp.codegen.McpTypes.MCP_ROLE_ENUM;

Expand Down Expand Up @@ -95,24 +93,29 @@ private void addPromptDescriptionMethod(Method.Builder builder, String descripti
private void addPromptMethod(Method.Builder builder, ClassModel.Builder classModel, TypedElementInfo element) {
List<String> parameters = new ArrayList<>();
TypeName returnType = element.signature().type();
Optional<String> role = element.findAnnotation(MCP_ROLE)
.flatMap(annotation -> annotation.value());
String role = element.findAnnotation(MCP_ROLE)
.flatMap(annotation -> annotation.value())
.orElse("ASSISTANT");

builder.name("prompt")
.returnType(returned -> returned.type(FUNCTION_REQUEST_LIST_PROMPT_CONTENT))
.returnType(returned -> returned.type(MCP_PROMPT_RESULT))
.addParameter(parameter -> parameter.type(MCP_PROMPT_REQUEST).name("request"))
.addAnnotation(Annotations.OVERRIDE);
builder.addContentLine("return request -> {");

for (TypedElementInfo param : element.parameterArguments()) {
if (isMcpType(parameters, param)) {
continue;
}
if (param.typeName().equals(MCP_PROMPT_REQUEST)) {
parameters.add("request");
continue;
}
if (param.typeName().equals(TypeNames.STRING)) {
parameters.add(param.elementName());
builder.addContent(param.typeName().classNameWithEnclosingNames())
.addContent(" ")
.addContent(param.elementName())
.addContent(" = request.parameters().get(\"")
.addContent(" = request.arguments().get(\"")
.addContent(param.elementName())
.addContentLine("\").asString().orElse(\"\");");
continue;
Expand All @@ -123,37 +126,35 @@ private void addPromptMethod(Method.Builder builder, ClassModel.Builder classMod
}

String params = String.join(", ", parameters);
if (returnType.equals(TypeNames.STRING)) {
builder.addContent("return ")
.addContent(List.class)
.addContent(".of(")
.addContent(MCP_PROMPT_CONTENTS)
.addContent(".textContent(delegate.")
if (returnType.equals(MCP_PROMPT_RESULT)) {
builder.addContent("return delegate.")
.addContent(element.elementName())
.addContent("(")
.addContent(params)
.addContent("), ")
.addContent(MCP_ROLE_ENUM)
.addContent(".")
.addContent(role.orElse("ASSISTANT"))
.addContentLine("));")
.decreaseContentPadding()
.addContentLine("};");
.addContentLine(");");
return;
}
if (returnType.equals(LIST_MCP_PROMPT_CONTENT)) {
builder.addContent("return delegate.")
if (returnType.equals(TypeNames.STRING)) {
builder.addContent("return ")
.addContent(MCP_PROMPT_RESULT)
.addContentLine(".builder()")
.increaseContentPadding()
.addContent(".addTextContent(t -> t.text(")
.addContent("delegate.")
.addContent(element.elementName())
.addContent("(")
.addContent(params)
.addContentLine(");")
.decreaseContentPadding()
.addContentLine("};");
.addContent(")).role(")
.addContent(MCP_ROLE_ENUM)
.addContent(".")
.addContent(role)
.addContentLine("))")
.addContentLine(".build();");
return;
}
throw new CodegenException(String.format("Wrong return type for method: %s. Supported types are: %s, or String.",
element.elementName(),
LIST_MCP_PROMPT_CONTENT.classNameWithTypes()));
MCP_PROMPT_RESULT.classNameWithTypes()));
}

private void addPromptArgumentsMethod(Method.Builder builder, TypedElementInfo element) {
Expand Down
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