MCP Plugin Configuration Reference

Every option of the Hive Gateway MCP plugin, its type and default.

useMCP(ctx, config) takes the gateway plugin context and an MCPConfig object. The MCPConfig type is exported by @graphql-hive/plugin-mcp so a configuration can be authored and type-checked separately, or loaded from YAML or JSON.

Server options

Option	Type	Default	Description
`name`	`string`	(required)	Server name reported in `initialize` responses
`version`	`string`	`"1.0.0"`	Server version reported in `initialize` responses
`title`	`string`		Human-readable server title
`description`	`string`		Human-readable server description
`instructions`	`string`		Free-text instructions included in `initialize` responses, for the model’s context
`icons`	`MCPIcon[]`		Server icons for client UIs (`src`, `mimeType`, `sizes`, `theme`)
`websiteUrl`	`string`		Server website URL
`protocolVersion`	`string`	`"2025-11-25"`	MCP protocol version to advertise
`path`	`string`	`"/mcp"`	HTTP path of the MCP endpoint
`log`	`Logger`		Logger instance; defaults to the gateway’s logger

Operation sources

Option	Type	Description
`operationsPath`	`string`	A `.graphql` file, or a directory of them, containing named operations and `@mcpTool` directives
`operationsStr`	`string`	The operations as a raw GraphQL string, as an alternative to a file
`loader`	`MCPOperationsLoader`	Load operations for each MCP request with access to its `request` and `serverContext`

Tools, resources and providers

Option	Type	Default	Description
`tools`	`MCPToolConfig[]`	`[]`	Tool definitions; see Tools
`resources`	`MCPResourceConfig[]`	`[]`	Static resources; see Resources
`resourceTemplates`	`MCPResourceTemplateConfig[]`	`[]`	Resource templates with URI patterns and handlers
`providers`	`object`		Description providers by name, e.g. `{ langfuse: {} }` or a custom `DescriptionProvider`
`suppressOutputSchema`	`boolean`	`false`	Omit the output schema from every tool in `tools/list`

Tool definition

Each entry of tools is an MCPToolConfig:

Field	Type	Description
`name`	`string`	Unique tool name exposed to clients (required)
`source`	`MCPToolSource`	`{ type: "inline", query }` or `{ type: "graphql", operationName, operationType, file? }` (required)
`tool`	`MCPToolOverrides`	`title`, `description`, `descriptionProvider`, `annotations`, `icons`, `execution.taskSupport`, `_meta`
`input`	`MCPInputOverrides`	`schema.properties.<variable>` with `description`, `examples`, `default`, `alias`, `hidden`, `descriptionProvider`
`output`	`MCPOutputOverrides`	`path`, `schema: false`, `contentAnnotations`, `descriptionProviders`
`hooks`	`MCPToolHooks`	`preprocess(args, context)` and `postprocess(result, args, context)`; the context carries `toolName`, `headers` and `query`

Directives

Available in operation files loaded through operationsPath, operationsStr or a loader:

Directive	Placement	Arguments	Effect
`@mcpTool`	Operation	`name`, `description`, `descriptionProvider`, `meta`	Registers the operation as a tool
`@mcpDescription`	Variable or selected field	`provider` (`<provider>:<prompt>` or `<provider>:<prompt>:<version>`)	Sets a dynamic description for the variable or output field
`@mcpHeader`	Variable	`name`	Hides the variable from the input schema and fills it from the named HTTP request header