Content
# MCP Server Bundle (Deprecated)
> [!CAUTION]
> This bundle is deprecated and will no longer receive updates.
> Please consider using alternative solutions for MCP server implementations.
> I encourage the use of [Symfony AI](https://github.com/symfony/ai) instead.
[](https://github.com/EdouardCourty/mcp-server-bundle/actions/workflows/php_ci.yml)
A powerful Symfony bundle for handling MCP (Model Context Protocol) server implementations, providing tools for JSON-RPC request handling and tool management.
_Read the [official MCP specification](https://modelcontextprotocol.io/docs/concepts/tools#overview)._
MCP Servers provide the fundamental building blocks for adding context to language models via MCP.
These primitives enable rich interactions between clients, servers, and language models:
- **Prompts**: Pre-defined templates or instructions that guide language model interactions
- **Resources**: Structured data or content that provides additional context to the model
- **Tools**: Executable functions that allow models to perform actions or retrieve information
The current MCP protocol supported version is `2025-06-18`, which is the latest stable version as of June 2025.
> [!WARNING]
> The specification of the Model Context Protocol (MCP) changes frequently.
> This bundle will evolve along with the specification, so please ensure you are using the latest version of the bundle.
> The CHANGELOG can be found [here](CHANGELOG.md).
## Table of Contents
- [Getting Started](#getting-started)
- [Installation](#installation)
- [Configuration](#configuration)
- [Tools](#tools)
- [Creating Tools](#creating-tools)
- [Tool Results](#tool-results)
- [Tool Events](#tool-events)
- [Input Schema Management](#input-schema-management)
- [JSON-RPC Integration](#json-rpc-integration)
- [Resources](#resources)
- [Creating Resources](#creating-resources)
- [Static Resources](#static-resources)
- [Templated Resources](#templated-resources)
- [Multiple Parameters](#multiple-parameters)
- [Parameter Type Casting](#parameter-type-casting)
- [Resource Results](#resource-results)
- [Resource Events](#resource-events)
- [JSON-RPC Integration](#json-rpc-integration-1)
- [Prompts](#prompts)
- [Creating Prompts](#creating-prompts)
- [Prompt Results](#prompt-results)
- [Prompt Events](#prompt-events)
- [JSON-RPC Integration](#json-rpc-integration-2)
- [JSON-RPC Methods](#json-rpc-methods)
- [Built-in Methods](#built-in-methods)
- [Custom Methods](#custom-methods)
- [Developer Experience](#developer-experience)
- [Contributing](#contributing)
- [License](#license)
## Getting Started
The MCP Server Bundle provides a structured way to create and manage tools that can be used by clients via JSON-RPC requests.
It includes features for MCP tool management, and JSON-RPC method handling.
This bundle is designed to be flexible and extensible, allowing developers to create custom tool handlers and method handlers as needed.
MethodHandlers and ToolHandlers are registered and autowired using attributes, making it easy to define and manage your own tools.
### Installation
1. Install the MCP Server Bundle via Composer:
```bash
composer require ecourty/mcp-server-bundle
```
2. Add the bundle to your `config/bundles.php` (if not using Symfony Flex):
```php
return [
// ...
Ecourty\McpServerBundle\McpServerBundle::class => ['all' => true],
];
```
3. Configure the routes in `config/routes/mcp.yaml`:
```yaml
mcp_controller:
path: /mcp
controller: mcp_server.entrypoint_controller
```
### Configuration
You can customize the MCP Server Bundle configuration in `config/packages/mcp_server.yaml`:
```yaml
mcp_server:
server:
name: 'My MCP Server' # The name of your MCP server, used in the initialization response
title: 'My MCP Server Display Name' # The title of your MCP server, used in the initialization response
version: '1.0.0' # The version of your MCP server, used in the initialization response
```
## Tools
Tools are the core components of the MCP Server Bundle. They allow you to define and manage custom logic that can be triggered by clients.
### Creating Tools
1. Create a new class that will handle your tool logic
2. Use the `#[AsTool]` attribute to register your tool
3. Optionally, define the input schema for your tool using a class with validation constraints and OpenAPI attributes
4. Implement the `__invoke` method to handle the tool logic and return a `ToolResult`
_As Tool classes are services within the Symfony application, any dependency can be injected in it, using the constructor, like any other service._
Example:
- Tool input schema class:
```php
#[OA\Schema(required: ['emailAddress', 'username'])]
class CreateUserSchema
{
#[Assert\Email]
#[Assert\NotBlank]
#[Assert\Length(min: 5, max: 255)]
#[OA\Property(description: 'The email address of the user', type: 'string', maxLength: 255, minLength: 5, nullable: false)]
public string $emailAddress;
#[Assert\NotBlank]
#[Assert\Length(min: 3, max: 50)]
#[OA\Property(description: 'The username of the user', type: 'string', maxLength: 50, minLength: 3, nullable: false)]
public string $username;
}
```
- Tool class:
```php
use App\Schema\CreateUserSchema;
use Ecourty\McpServerBundle\Attribute\AsTool;
use Ecourty\McpServerBundle\Attribute\ToolAnnotations;
use Ecourty\McpServerBundle\IO\TextToolResult;
use Ecourty\McpServerBundle\IO\ToolResult;
#[AsTool(
name: 'create_user', # Unique identifier for the tool, used by clients to call it
description: 'Creates a new user in the system', # This description is used by LLMs to understand the tool's purpose
annotations: new ToolAnnotations(
title: 'Create a user', // A human-readable title for the tool, useful for documentation
readOnlyHint: false, // Defines the request is not read-only (creates a user)
destructiveHint: false, // Defines the request is not destructive (does not delete data)
idempotentHint: false, // Defines the request cannot be repeated without changing the state
openWorldHint: false, // The tool does not interact with external systems
)
)]
class CreateUserTool
{
public function __invoke(CreateUserSchema $createUserSchema): ToolResult
{
// Your logic here...
return new ToolResult([new TextToolResult('User created successfully!')]);
}
}
```
### Tool Results
The MCP specification states that tool results should consist of an array of objects.
The bundle provides several result types that can be combined in a single `ToolResult` object:
- `TextToolResult`: For text-based results
- `ImageToolResult`: For image results
- `AudioToolResult`: For audio results
- `ResourceToolResult`: For file or resource results
All tool results must be wrapped in a `ToolResult` object, which can contain multiple results and handle error state.
Example:
```php
<?php
use App\Schema\ReadFileSchema;
use Ecourty\McpServerBundle\Attribute\AsTool;
use Ecourty\McpServerBundle\IO\TextToolResult;
use Ecourty\McpServerBundle\IO\ToolResult;
#[AsTool(name: 'read_file', description: 'Reads a file and returns its content')]
class MyTool
{
public function __invoke(ReadFileSchema $payload): ToolResult
{
$fileContent = file_get_contents($payload->filePath);
$anotherFileContent = file_get_contents($payload->anotherFilePath);
// Create individual results
$textResult = new TextToolResult($fileContent);
$anotherTextResult = new TextToolResult($anotherFileContent);
// Combine them in a ToolResult
return new ToolResult([
$textResult,
$anotherTextResult,
]);
}
}
```
Error handling example:
```php
use Ecourty\McpServerBundle\IO\TextToolResult;
use Ecourty\McpServerBundle\IO\ToolResult;
class MyTool
{
public function __invoke(): ToolResult
{
try {
// Your logic here...
return new ToolResult([
new TextToolResult('Success!')
]);
} catch (\Exception $e) {
return new ToolResult(
[new TextToolResult($e->getMessage())],
isError: true
);
}
}
}
```
The `ToolResult` class provides the following features:
- Combine multiple results of different types
- Handle error state
- Automatic serialization to the correct format
- Type safety for all results
### Tool Events
The bundle provides several events that you can listen to:
- `ToolCallEvent`: Dispatched before a tool is called, contains the tool name and input data
- `ToolResultEvent`: Dispatched after a tool has been called, contains the result of the tool call
- `ToolCallExceptionEvent`: Dispatched when a tool throws an exception, contains the tool name, input data and throwable
Example of event listener:
```php
use Ecourty\McpServerBundle\Event\ToolCallEvent;
use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
#[AsEventListener(event: ToolCallEvent::class)]
class ToolCallListener
{
public function __invoke(ToolCallEvent $event): void
{
// Your logic here...
}
}
```
### Input Schema Management
The bundle provides robust input validation and sanitization through schema-based deserialization.
Input schemas are extracted from the `__invoke` method of classes with the `#[AsTool]` attribute, allowing you to define the expected input structure and validation rules.
1. Define your input schema class:
```php
<?php
use OpenApi\Attributes as OA;
use Symfony\Component\Validator\Constraints as Assert;
class CreateUser
{
#[Assert\NotBlank]
#[Assert\Length(min: 2, max: 50)]
#[OA\Property(type: 'string', description: 'The name of the user', nullable: false)]
private string $name;
#[Assert\NotBlank]
#[Assert\Email]
#[OA\Property(type: 'string', description: 'The email address of the user', nullable: false)]
private string $email;
// Getters and setters...
}
```
2. The bundle will automatically:
- Understand the OA attributes for OpenAPI-based documentation in `tools/list`
- Deserialize incoming JSON data into your schema class
- Validate all constraints defined in your schema
- Sanitize input data
This ensures that your tool handlers always receive properly validated and sanitized data.
### JSON-RPC Integration
- **`tools/list`**: Lists all available tools and their definitions.
- **`tools/call`**: Executes a tool by name, with the provided input data.
## Resources
Resources are data sources that can be accessed by clients via their URI.
They can represent files, database records, or any other data that can be identified by a URI.
### Creating Resources
1. Create a new class that will handle your resource logic
2. Use the `#[AsResource]` attribute to register your resource
3. Define the URI pattern for your resource (static or templated)
4. Implement the `__invoke` method to handle the resource logic and return a `ResourceResult`
_As Resource classes are services within the Symfony application, any dependency can be injected in it, using the constructor, like any other service._
#### Static Resources
Static resources have a fixed URI that doesn't change. They are useful for resources that don't require parameters.
Example:
```php
<?php
use Ecourty\McpServerBundle\Attribute\AsResource;
use Ecourty\McpServerBundle\IO\Resource\ResourceResult;
use Ecourty\McpServerBundle\IO\Resource\TextResource;
#[AsResource(
uri: 'file://robots.txt',
name: 'robots_txt',
title: 'Get the Robots.txt file',
description: 'This resource returns the content of the robots.txt file.',
mimeType: 'text/plain',
)]
class RobotsFileResource
{
private const string FILE_PATH = __DIR__ . '/../Resources/robots.txt';
public function __invoke(): ResourceResult
{
$fileContent = (string) file_get_contents(self::FILE_PATH);
$encodedFileContent = base64_encode($fileContent);
return new ResourceResult([
new BinaryResource('file://robots.txt', 'text/plain', $encodedFileContent),
]);
}
}
```
#### Templated Resources
Templated resources use URI templates with parameters enclosed in curly braces (e.g., `{id}`). These parameters are automatically extracted from the URI and passed to the `__invoke` method as arguments.
Example:
```php
<?php
use Ecourty\McpServerBundle\Attribute\AsResource;
use Ecourty\McpServerBundle\IO\Resource\ResourceResult;
use Ecourty\McpServerBundle\IO\Resource\TextResource;
#[AsResource(
uri: 'database://user/{id}',
name: 'user_data',
title: 'Get User Data',
description: 'Gathers the data of a user by their ID.',
mimeType: 'application/json',
)]
class UserResource
{
public function __construct(
private readonly EntityManagerInterface $entityManager,
private readonly SerializerInterface $serializer,
) {
}
public function __invoke(int $id): ResourceResult
{
$user = $this->entityManager->find(User::class, $id);
if ($user === null) {
throw new \RuntimeException('User not found');
}
$stringifiedUserData = $this->serializer->serialize($user, 'json');
return new ResourceResult([
new TextResource(
uri: 'database://user/' . $id,
mimeType: 'application/json',
text: $stringifiedUserData,
),
]);
}
}
```
In this example:
- The URI template `database://user/{id}` defines a parameter named `id`
- When a client requests `database://user/123`, the parameter `123` is extracted
- The `__invoke` method receives `123` as an `int` parameter (automatic type casting is performed)
- The resource returns user data for ID 123
#### Multiple Parameters
You can define multiple parameters in a single URI template:
```php
#[AsResource(
uri: 'api://users/{userId}/posts/{postId}',
name: 'user_post',
title: 'Get User Post',
description: 'Retrieves a specific post by a user.',
mimeType: 'application/json',
)]
class UserPostResource
{
public function __invoke(int $userId, int $postId): ResourceResult
{
// Your logic here...
$post = $this->postRepository->findByUserAndPost($userId, $postId);
return new ResourceResult([
new TextResource(
uri: "api://users/{$userId}/posts/{$postId}",
mimeType: 'application/json',
text: json_encode($post),
),
]);
}
}
```
#### Parameter Type Casting
The bundle automatically casts URI parameters to the appropriate types based on the method signature:
- `int` parameters are cast to integers
- `float` parameters are cast to floats
- `bool` parameters are cast to booleans
- `string` parameters remain as strings
- `array` parameters are JSON-decoded into arrays using `json_decode` if they are JSON strings
### Resource Results
The [MCP specification](https://modelcontextprotocol.io/specification/2025-06-18/server/resources#reading-resources) states that resource results should consist of an array of resource objects.
The bundle provides several result types that can be combined in a single `ResourceResult` object:
- `TextResource`: For text-based content (JSON, XML, plain text, etc.)
- `BinaryResource`: For binary content (images, audio, video, files, etc.), should be base-64 encoded
All resource results must be wrapped in a `ResourceResult` object, which can contain multiple resources.
Example:
```php
<?php
use Ecourty\McpServerBundle\IO\Resource\ResourceResult;
use Ecourty\McpServerBundle\IO\Resource\TextResource;
use Ecourty\McpServerBundle\IO\Resource\BinaryResource;
#[AsResource(
// ...
)]
class MyResource
{
public function __invoke(): ResourceResult
{
$jsonData = json_encode(['status' => 'success']);
$imageData = base64_encode(file_get_contents('image.jpg'));
return new ResourceResult([
new TextResource(
uri: 'api://data/status',
mimeType: 'application/json',
text: $jsonData,
),
new BinaryResource(
uri: 'file://image.jpg',
mimeType: 'image/jpeg',
blob: $imageData,
),
]);
}
}
```
The `ResourceResult` class provides the following features:
- Combine multiple resources of different types
- Automatic serialization to the correct format
- Type safety for all resources
### Resource Events
The bundle provides several events that you can listen to:
- `ResourceReadEvent`: Dispatched before a resource is read, contains the URI
- `ResourceReadResultEvent`: Dispatched after a resource has been read, contains the URI and results
Example of event listener:
```php
<?php
use Ecourty\McpServerBundle\Event\ResourceReadEvent;
use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
#[AsEventListener(event: ResourceReadEvent::class)]
class ResourceReadListener
{
public function __invoke(ResourceReadEvent $event): void
{
// Your logic here...
// Log the resource access, add caching, etc.
}
}
```
### JSON-RPC Integration
- **`resources/list`**: Lists all available direct (static) resources and their definitions.
- **`resources/templates/list`**: Lists all available templated resources and their definitions.
- **`resources/read`**: Retrieves a resource by its URI, automatically matching templated resources and extracting parameters.
## Prompts
Prompts are reusable templates that can be dynamically generated and returned by the MCP server.
They are useful for providing context, instructions, or any structured message to clients, and can accept arguments for dynamic content.
### Creating Prompts
1. **Define a prompt class**
- Use the `#[AsPrompt]` attribute to register your prompt.
- The class should implement the `__invoke` method, which optionally receives an `ArgumentCollection` and returns a `PromptResult`.
- Arguments are defined using the `Argument` class (name, description, required, allowUnsafe), within the `#[AsPrompt]` declaration.
**Example:**
```php
<?php
namespace App\Prompt;
use Ecourty\McpServerBundle\Attribute\AsPrompt;
use Ecourty\McpServerBundle\Enum\PromptRole;
use Ecourty\McpServerBundle\IO\Prompt\Content\TextContent;
use Ecourty\McpServerBundle\Prompt\Argument;
use Ecourty\McpServerBundle\IO\Prompt\PromptResult;
use Ecourty\McpServerBundle\IO\Prompt\PromptMessage;
use Ecourty\McpServerBundle\Prompt\ArgumentCollection;
#[AsPrompt(
name: 'code_review', // Unique identifier for the prompt,
description: 'Ask for a code review on a provided piece of code', // Description of the prompt
arguments: [
new Argument(name: 'code', description: 'The code snippets to review', required: true, allowUnsafe: true), // Required argument
new Argument(name: 'language', description: 'The name of the person to greet', required: false), // Optional argument
new Argument(name: 'reviewer_level', description: 'The level of review (senior / intermediate / junior...)', required: false), // Optional argument
],
)]
class CodeReviewPrompt
{
public function __invoke(ArgumentCollection $arguments): PromptResult
{
$code = $arguments->get('code');
$language = $arguments->get('language');
$reviewerLevel = $arguments->get('reviewer_level') ?: 'senior';
$systemMessage = <<<PROMPT
You are a $reviewerLevel code reviewer.
You will be provided with a piece of code in $language.
Your task is to review the code and provide feedback on its quality, readability, and any potential issues.
PROMPT;
$userMessage = <<<PROMPT
Review the following code snippet: $code
PROMPT;
return new PromptResult(
description: 'Code Review Prompt',
messages: [
new PromptMessage(
role: PromptRole::SYSTEM,
content: new TextContent($systemMessage),
),
new PromptMessage(
role: PromptRole::USER,
content: new TextContent($userMessage),
),
]
);
}
}
```
### Prompt Results
A prompt must return an instance of `PromptResult`, which contains:
- A `description` (string)
- An array of `PromptMessage` objects (each with a role and content)
**Example:**
```php
return new PromptResult(
description: 'Greeting',
messages: [
new PromptMessage(role: PromptRole::SYSTEM, content: new TextContent('You are a friendly assistant.')),
new PromptMessage(role: PromptRole::USER, content: new TextContent('Hello, how are you?')),
]
);
```
### Prompt Events
The bundle provides several events for prompts:
- `PromptGetEvent`: Dispatched before a prompt is generated
- `PromptResultEvent`: Dispatched after a prompt is generated
- `PromptExceptionEvent`: Dispatched if an error occurs during prompt generation
**Example of event listener:**
```php
use Ecourty\McpServerBundle\Event\Prompt\PromptExceptionEvent;
use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
#[AsEventListener(event: PromptExceptionEvent::class)]
class PromptGetListener
{
public function __invoke(PromptExceptionEvent $event): void
{
// Your logic here...
}
}
```
### JSON-RPC Integration
- **`prompts/list`**: Lists all available prompts and their definitions.
- **`prompts/get`**: Retrieves and generates a prompt by name, with arguments.
## JSON-RPC Methods
The bundle provides a robust system for handling JSON-RPC requests.
### Built-in Methods
1. **`initialize`**
- Called when a client first connects to the server
- Returns server information and capabilities
- Essential for client-server handshake
2. **`tools/list`**
- Lists all available tools on the server
- Returns tool metadata including names, descriptions, and input schemas
- Used by clients to discover available tools
3. **`tools/call`**
- Executes a specific tool
- Handles input validation and tool execution
- Returns the tool's result or error information
4. **`prompts/list`**
- Lists all available prompts and their definitions
- Returns prompt names, descriptions, and argument schemas
- Useful for clients to discover available prompts
5. **`prompts/get`**
- Retrieves a specific prompt by its name and generates it with the provided arguments
- Validates and sanitizes arguments, then returns the generated prompt content
- Returns an error if the prompt is not found or arguments are invalid
6. **`resources/list`**
- Lists all available static resources and their definitions
- Returns resource URIs, descriptions, and metadata
- Useful for clients to discover available resources
7. **`resources/templates/list`**
- Lists all available static and templated resources
- Returns resource URIs, descriptions, and metadata
- Useful for clients to discover available template resources
8. **`resources/read`**
- Reads a specific resource by its URI
- Automatically matches templated resources and extracts parameters
- Returns the resource content or an error if the resource is not found
These methods are automatically registered and handled by the bundle. You don't need to implement them yourself.
### Custom Methods
You can create your own JSON-RPC method handlers for additional functionality:
1. Create a new class that implements the `MethodHandlerInterface`
2. Use the `#[AsMethodHandler]` attribute to register your handler
Example:
```php
<?php
use Ecourty\McpServerBundle\Attribute\AsMethodHandler;
use Ecourty\McpServerBundle\MethodHandler\MethodHandlerInterface;
#[AsMethodHandler(
method: 'my_method',
)]
class MyMethodHandler implements MethodHandlerInterface
{
public function handle(JsonRpcRequest $params): array
{
// Your request handling logic here
// ...
return ['result' => 'success'];
}
}
```
#### Method Handler Attributes
The `#[AsMethodHandler]` attribute supports:
- `method` (string, required): The JSON-RPC method name
## Developer Experience
The bundle provides several tools to help you during development:
### Debug Command
1. The `debug:mcp-tools` command helps you inspect and debug your MCP tools:
```bash
# List all registered tools
php bin/console debug:mcp-tools
# Get detailed information about a specific tool
php bin/console debug:mcp-tools my_tool_name
```
This command is particularly useful for:
- Verifying tool registration
- Checking input schemas
- Validating tool annotations
2. The `debug:mcp-prompts` command helps you inspect and debug your MCP prompts:
```bash
# List all registered prompts
php bin/console debug:mcp-prompts
# Get detailed information about a specific prompt
php bin/console debug:mcp-prompts my_prompt_name
```
This command is particularly useful for:
- Verifying prompt registration
- Checking argument
3. The `debug:mcp-resources` command helps you inspect and debug your MCP resources:
```bash
# List all registered resources
php bin/console debug:mcp-resources
# Get detailed information about a specific resource
php bin/console debug:mcp-resources my_resource_name
```
This command is particularly useful for:
- Verifying resource registration
- Checking URI patterns
## Contributing
Contributions to the MCP Server Bundle are welcome! Here's how you can help:
1. Fork the repository
2. Create a new branch for your feature
3. Make your changes
4. Submit a pull request
Please ensure your code follows our coding standards and includes appropriate tests.
### Development Setup
1. Fork and clone the repository
2. Install dependencies
```bash
composer install
```
3. Make your chages
4. Fix the code style and run PHPStan
```bash
composer fix-cs
composer phpstan
```
5. Run the tests
```bash
composer test
```
## License
This bundle is licensed under the MIT License. See the [LICENSE](LICENSE) file for details.
