Ein generischer MCP-Server (Model Context Protocol), der jede GraphQL-API mit Claude Code verbindet. Er untersucht Ihr GraphQL-Schema und stellt jede Query und Mutation als einzelnes Tool bereit, sodass Claude direkt mit Ihrer API interagieren kann.
Beim Start führt der Server folgende Schritte aus:
Er sucht nach einer schema-introspection.json-Datei im Arbeitsverzeichnis (schnell, kein Netzwerkaufruf)
Falls nicht gefunden, führt er eine Live-Introspektion gegen die GRAPHQL_INTROSPECTION_URL durch
Er registriert ein Tool pro Query (query__<name>) und eines pro Mutation (mutation__<name>)
Er registriert immer ein generisches execute_graphql-Fallback-Tool und ein get_type_details-Explorer-Tool
Related MCP server: GraphQL MCP Server
Node.js >= 18
npm install -g mcp-graphql-bridgegit clone https://github.com/murilopereira/mcp-graphql-bridge.git
cd mcp-graphql-bridge
npm install
npm run buildVariable | Erforderlich | Beschreibung |
| Ja | Endpunkt für Queries und Mutationen |
| Ja | Endpunkt für die Schema-Introspektion (kann derselbe wie oben sein) |
| Ja | Bearer-Token für die Authentifizierung |
Sie können diese in einer .env-Datei im Projektstammverzeichnis festlegen:
GRAPHQL_API_URL=https://your-api.example.com/graphql
GRAPHQL_INTROSPECTION_URL=https://your-api.example.com/graphql
GRAPHQL_TOKEN=your-bearer-tokenOder übergeben Sie sie direkt über den Befehl claude mcp add (siehe unten).
Standardmäßig untersucht der Server Ihr Schema live beim Start – es ist keine Datei erforderlich. Verwenden Sie diesen Schritt nur, wenn Ihre API die Introspektion in der Produktion deaktiviert hat oder Sie schnellere Startzeiten wünschen:
curl -s -X POST https://your-api.example.com/graphql \
-H "Content-Type: application/json" \
-H "Authorization: Bearer your-bearer-token" \
-d '{"query":"{ __schema { queryType { fields { name description args { name description defaultValue type { kind name ofType { kind name ofType { kind name ofType { kind name } } } } } type { kind name ofType { kind name ofType { kind name } } } } } mutationType { fields { name description args { name description defaultValue type { kind name ofType { kind name ofType { kind name ofType { kind name } } } } } type { kind name ofType { kind name ofType { kind name } } } } } } }"}' \
> schema-introspection.jsonBei Installation über npm:
claude mcp add --transport stdio \
--env GRAPHQL_API_URL=https://your-api.example.com/graphql \
--env GRAPHQL_INTROSPECTION_URL=https://your-api.example.com/graphql \
--env GRAPHQL_TOKEN=your-bearer-token \
graphql-bridge -- mcp-graphql-bridgeBei Klonen aus dem Quellcode:
claude mcp add --transport stdio \
--env GRAPHQL_API_URL=https://your-api.example.com/graphql \
--env GRAPHQL_INTROSPECTION_URL=https://your-api.example.com/graphql \
--env GRAPHQL_TOKEN=your-bearer-token \
graphql-bridge -- node /absolute/path/to/mcp-graphql-bridge/dist/index.jsWichtig: Stellen Sie sicher, dass Sie
mcp-graphql-bridge/dist/index.js(die kompilierte Ausgabe) verwenden, nichtmcp-graphql-bridge/index.js. Der TypeScript-Quellcode muss zuerst mitnpm run builderstellt werden, und der Einstiegspunkt befindet sich imdist/-Ordner.
.mcp.json)claude mcp add --transport stdio --scope project \
--env GRAPHQL_API_URL=https://your-api.example.com/graphql \
--env GRAPHQL_INTROSPECTION_URL=https://your-api.example.com/graphql \
--env GRAPHQL_TOKEN=your-bearer-token \
graphql-bridge -- mcp-graphql-bridgeHinweis: Verwenden Sie absolute Pfade. Alle
--env- und--transport-Flags müssen vor dem Servernamen stehen.
claude mcp listFühren Sie dann in einer Claude Code-Sitzung /mcp aus, um die verfügbaren Server und Tools anzuzeigen.
Tool | Beschreibung |
| Ein Tool pro GraphQL-Query-Feld |
| Ein Tool pro GraphQL-Mutationsfeld |
| Generisches Fallback – führt jede Query oder Mutation aus |
| Felder eines bestimmten GraphQL-Typs erkunden |
Alle pro-Operation-Tools akzeptieren ein spezielles __fields-Argument, in dem Sie ein benutzerdefiniertes GraphQL-Auswahlset angeben können (z. B. { id name status }). Wenn es weggelassen wird, werden nur skalare Felder zurückgegeben.
docker build -t mcp-graphql-bridge .claude mcp add --transport stdio \
--env GRAPHQL_API_URL=https://your-api.example.com/graphql \
--env GRAPHQL_INTROSPECTION_URL=https://your-api.example.com/graphql \
--env GRAPHQL_TOKEN=your-bearer-token \
graphql-bridge -- docker run -i --rm \
-e GRAPHQL_API_URL -e GRAPHQL_INTROSPECTION_URL -e GRAPHQL_TOKEN \
mcp-graphql-bridgeHinweis: Das
-i-Flag (ohne-t) ist erforderlich – es hält stdin für das MCP-stdio-Protokoll offen.
npm run dev # watch mode: rebuilds and restarts on file changes
npm run build # one-off TypeScript compile
npm start # run the compiled serverWenn Sie eine Fehlermeldung wie diese sehen:
Error: Cannot find module '/path/to/mcp-graphql-bridge/index.js'Sie verweisen auf die falsche Datei. Der TypeScript-Quellcode muss zuerst kompiliert werden, und der Einstiegspunkt befindet sich im dist/-Ordner:
Korrekter Pfad: /path/to/mcp-graphql-bridge/dist/index.js
Falscher Pfad: /path/to/mcp-graphql-bridge/index.js
Lösung:
Stellen Sie sicher, dass Sie npm run build ausgeführt haben (erstellt den dist/-Ordner)
Aktualisieren Sie Ihre MCP-Konfiguration, um den vollständigen Pfad mit Endung /dist/index.js zu verwenden
Wenn der Server startet, aber "Schema introspection failed" anzeigt, hat Ihre GraphQL-API möglicherweise die Introspektion in der Produktion deaktiviert. Verwenden Sie den curl-Befehl in Schritt 3 der Einrichtung, um eine schema-introspection.json-Datei vorab zu generieren.
Führen Sie claude mcp list aus, um zu überprüfen, ob der Server registriert ist
Führen Sie /mcp in einer Claude Code-Sitzung aus, um die verfügbaren Tools anzuzeigen
Überprüfen Sie, ob alle erforderlichen Umgebungsvariablen gesetzt sind (GRAPHQL_API_URL, GRAPHQL_INTROSPECTION_URL, GRAPHQL_TOKEN)
Execute any GraphQL query or mutation against the API. Use this when no specific tool exists for your operation.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | Full GraphQL query or mutation string including selection set | |
| variables | No | Variables for the operation | |
| bearer_token | No | Bearer token to authenticate this request (overrides GRAPHQL_TOKEN) | |
| custom_headers | No | Additional request headers as key-value pairs, e.g. {"X-Tenant-ID": "abc"} |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so description must disclose behavioral traits. It does not mention potential side effects of mutations, authentication requirements (beyond parameter hints), rate limits, or error handling. The description is too minimal to convey safe usage.
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?
Two sentences pack purpose and usage guidelines with zero waste, frontloading the key action and fallback use.
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?
No output schema; description does not explain return format, errors, or the fact that the endpoint is pre-configured. Despite the complexity of a generic GraphQL executor, the description is incomplete.
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?
Schema description coverage is 100% (all 4 parameters have descriptions). The description adds no additional parameter semantics. Baseline 3 is appropriate.
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 'Execute any GraphQL query or mutation against the API', specifying the verb and resource. It distinguishes itself from sibling 'get_type_details' by being a generic executor.
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?
Explicitly says 'Use this when no specific tool exists for your operation', providing clear when-to-use guidance. No exclusions, but the instruction is direct.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Get fields of a specific GraphQL type to know what to put in __fields
| Name | Required | Description | Default |
|---|---|---|---|
| typeName | Yes | GraphQL type name, e.g. 'Repository', 'User', 'Issue' |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose all behavioral traits. It indicates a read operation, but does not mention error handling (e.g., invalid type name), response structure, or any side effects.
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, focused sentence with no extraneous text. It is front-loaded and efficient.
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?
Despite the tool's simplicity, the description omits output details. The agent does not know whether the response returns field names, types, or full schema; this is critical given no output schema.
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 already covers the single parameter with a clear description and examples. The tool description adds no extra meaning beyond prompting usage of '__fields'.
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 gets fields of a specific GraphQL type and its purpose in GraphQL introspection. However, it does not differentiate from sibling tool execute_graphql, which may also retrieve type information.
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 phrase 'to know what to put in __fields' implies a use case, but there is no explicit guidance on when to use this tool versus execute_graphql, nor any when-not-to-use advice.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
v2.1.0execute_graphql2 fields changedInput schema / properties / bearer_tokenAdded value: +{
+ "description": "Bearer token to authenticate this request (overrides GRAPHQL_TOKEN)",
+ "type": "string"
+}Input schema / properties / custom_headersAdded value: +{
+ "additionalProperties": {
+ "type": "string"
+ },
+ "description": "Additional request headers as key-value pairs, e.g. {\"X-Tenant-ID\": \"abc\"}",
+ "type": "object"
+}get_type_details1 field changedInput schema / properties / typeName / descriptionPrevious value: -"GraphQL type name, e.g. 'Machine', 'WorkOrder', 'Shift'"New value: +"GraphQL type name, e.g. 'Repository', 'User', 'Issue'"v1.0.1execute_graphqlget_type_detailsScored across 2 tools
The two tools serve clearly distinct purposes: executing GraphQL operations vs. retrieving type metadata. No overlap in functionality.
Both tool names follow a consistent verb_noun pattern using snake_case (execute_graphql, get_type_details), making the intent clear and predictable.
For a GraphQL bridge, two tools is minimal but still covers the essential operations of executing queries and exploring types. Slightly under-scoped but reasonable.
The tool surface covers core GraphQL operations (any query/mutation) and type introspection. Minor gaps exist (e.g., no dedicated tool for listing mutations), but the generic execute tool and type details suffice for agents familiar with GraphQL.
The Grafbase MCP server sits in front of a GraphQL API and exposes an MCP protocol-compliant interface that allows AI agents and LLMs to explore and query GraphQL APIs using natural language. It provides tools to search schemas, introspect types and fields, and execute GraphQL queries while minimizing context bloat by returning only relevant schema subsets, with built-in support for authentication, authorization, and configurable access control.
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