mcp4gql
mcp4gql - Servidor MCP GraphQL

Este proyecto es un servidor Node.js/TypeScript que implementa el Protocolo de Contexto de Modelo (MCP). Actúa como puente, permitiendo que los clientes MCP (como Cursor) interactúen con una API GraphQL de destino.
Características
Servidor MCP: implementa la clase
ServerMCP de@modelcontextprotocol/sdk.Transporte Stdio: se comunica con los clientes a través de entrada/salida estándar.
Cliente GraphQL: utiliza
axiospara enviar solicitudes al punto final GraphQL configurado.Herramientas genéricas de GraphQL: expone las siguientes herramientas a los clientes MCP:
introspectGraphQLSchema: obtiene el esquema de API GraphQL de destino mediante introspección.executeGraphQLOperation: ejecuta consultas o mutaciones GraphQL arbitrarias contra la API de destino, tomandoquery,variablesyoperationNameopcional como entrada.
Related MCP server: mcp-graphql
Configuración
El servidor requiere las siguientes variables de entorno:
GRAPHQL_ENDPOINT: la URL de la API GraphQL de destino.AUTH_TOKEN: un token portador para un encabezadoAuthorization: Bearer <token>opcional para autenticarse con la API GraphQL.
Configuración del cliente
Para permitir que clientes como Cursor o Claude Desktop utilicen las herramientas proporcionadas por este servidor, debe configurarlos para ejecutar el comando npx .
Cursor
Vaya a Configuración del cursor MCP (Cursor > Configuración > Configuración del cursor > MCP)
Vaya a + Agregar nuevo servidor MCP global
Agregue lo siguiente a su configuración de Cursor MCP:
{ "mcpServers": { "mcp4gql": { "command": "npx", "type": "stdio", "args": ["-y", "mcp4gql"], "env": { "GRAPHQL_ENDPOINT": "YOUR_GRAPHQL_ENDPOINT_URL", "AUTH_TOKEN": "YOUR_OPTIONAL_AUTH_TOKEN" } } } }
Escritorio de Claude
Abra la configuración de Claude Desktop (Claude > Configuración).
Vaya a Desarrollador > Editar configuración.
Agregar a la configuración:
{ "mcpServers": { "mcp4gql": { "command": "npx", "args": ["-y", "mcp4gql"], "env": { "GRAPHQL_ENDPOINT": "YOUR_GRAPHQL_ENDPOINT_URL", "AUTH_TOKEN": "YOUR_OPTIONAL_AUTH_TOKEN" } } } }
Una vez configurado, el cliente MCP debería poder listar y llamar a las herramientas introspectGraphQLSchema y executeGraphQLOperation proporcionadas por este servidor cuando sea necesario. Recuerde configurar las variables de entorno necesarias ( GRAPHQL_ENDPOINT y, opcionalmente, AUTH_TOKEN ) para que el servidor pueda conectarse a su API.
Available Tools
2 toolsexecuteGraphQLOperationA
Executes an arbitrary GraphQL query or mutation against the target API. Use introspectGraphQLSchema first to understand the available operations.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | The GraphQL query string to execute. | |
| variables | No | An optional object containing variables for the query. | |
| operationName | No | An optional name for the operation, if the query contains multiple operations. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. While it mentions executing 'query or mutation,' it lacks critical details such as authentication requirements, rate limits, error handling, or whether it's read-only or destructive. This is a significant gap for a tool that can perform mutations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is highly concise and front-loaded, consisting of only two sentences. The first sentence states the core purpose, and the second provides essential usage guidance. Every sentence earns its place without redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (executing arbitrary GraphQL operations with potential mutations) and lack of annotations and output schema, the description is incomplete. It covers purpose and usage guidelines well but fails to address behavioral aspects like safety, permissions, or response format, which are crucial for such a flexible tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema description coverage is 100%, so the schema already documents all three parameters (query, variables, operationName) with clear descriptions. The description does not add any parameter-specific details beyond what the schema provides, which aligns with the baseline score of 3 when schema coverage is high.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: 'Executes an arbitrary GraphQL query or mutation against the target API.' It specifies the verb ('executes') and resource ('GraphQL query or mutation'), and distinguishes it from the sibling tool 'introspectGraphQLSchema' by mentioning it as a prerequisite for understanding available operations.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit guidance on when to use this tool: 'Use introspectGraphQLSchema first to understand the available operations.' This clearly indicates a prerequisite and distinguishes it from the sibling tool, offering a specific alternative for schema exploration.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
introspectGraphQLSchemaB
Fetches the schema of the target GraphQL API using introspection. Returns the schema in JSON format.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses the tool fetches schema via introspection and returns JSON, which is useful behavioral context. However, it lacks details on permissions, rate limits, error handling, or whether it's read-only/destructive, leaving gaps for a mutation-sensitive context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, efficient sentence that front-loads key information (fetches schema, uses introspection, returns JSON) with no wasted words. It's appropriately sized for a simple tool with no parameters.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity (0 parameters, no output schema, no annotations), the description is adequate but minimal. It explains what the tool does and the return format, but lacks context on behavioral traits like safety or performance, which could be important for an API introspection tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema has 0 parameters with 100% coverage, so no parameter documentation is needed. The description appropriately doesn't discuss parameters, focusing on the tool's purpose instead, which aligns with the baseline for zero parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action ('fetches') and resource ('schema of the target GraphQL API'), specifying it uses introspection and returns JSON format. It distinguishes from the sibling 'executeGraphQLOperation' by focusing on schema retrieval rather than operation execution, though it doesn't explicitly name the sibling for differentiation.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance on when to use this tool versus alternatives is provided. The description implies usage for schema introspection, but it doesn't mention prerequisites, when not to use it, or reference the sibling tool for operational queries.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
2 tool updates
- First observed
executeGraphQLOperation - First observed
introspectGraphQLSchema
TDQS
Scored across 2 tools
The two tools have clearly distinct purposes: introspectGraphQLSchema fetches the schema, while executeGraphQLOperation executes queries/mutations. There is no overlap or ambiguity between them, making it easy for an agent to select the correct tool.
Both tools follow a verb_noun pattern (introspectGraphQLSchema, executeGraphQLOperation), but they use camelCase instead of snake_case. This is a minor deviation from a common convention, but the pattern is consistent and readable across the set.
With only 2 tools, the server feels thin for a GraphQL client purpose. While the tools cover introspection and execution, typical GraphQL interactions might benefit from additional utilities like schema validation or query building, making this count borderline too few.
The tools cover core GraphQL operations (introspection and execution), but there are notable gaps. For example, there are no tools for schema exploration, query validation, or handling subscriptions, which could limit an agent's ability to fully interact with a GraphQL API.
Maintenance
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