Apollo MCP Server

--- title: Define MCP Tools --- You can manually define the GraphQL operations that are exposed by Apollo MCP Server as MCP tools. You can define these operations using: - Local operation files - Operation collections - Persisted query manifests - GraphOS-managed persisted queries Alternatively, you can let an AI model read your graph schema via GraphQL introspection and have it determine the available operations. ## Define GraphQL operations for tools ### From operation files An operation file is a `.graphql` file containing a single GraphQL operation. <CodeColumns cols={2}> ```graphql title="Example operation GetForecast" query GetForecast($coordinate: InputCoordinate!) { forecast(coordinate: $coordinate) { detailed } } ``` ```graphql title="Example operation GetWeatherData" query GetAllWeatherData($coordinate: InputCoordinate!, $state: String!) { forecast(coordinate: $coordinate) { detailed } alerts(state: $state) { severity description instruction } } ``` </CodeColumns> Use the `operations` option to provide the MCP Server with a list of operation files. For each operation file you provide, the MCP Server creates an MCP tool that calls the corresponding GraphQL operation. You can also use the `operations` option to specify a directory. The server then loads all files with a `.graphql` extension in that directory as operations. Files and directories specified with `operations` are hot reloaded. When you specify a file, the MCP tool is updated when the file contents are modified. When you specify a directory, operations exposed as MCP tools are updated when files are added, modified, or removed from the directory. ### From operation collections For graphs managed by GraphOS, Apollo MCP Server can retrieve operations from an [operation collection](/graphos/platform/explorer/operation-collections). Use GraphOS Studio Explorer to create and manage operation collections. #### Configuring the MCP Server to use a GraphOS operation collection To use a GraphOS operation collection, you must set your graph credentials (`APOLLO_GRAPH_REF` and `APOLLO_KEY`) as environment variables. Each graph variant has its own default MCP Tools Collection, but you can specify any shared collection by using `operations.source: collection`. Specify the collection to use with the `operations.id` option. To view the ID of a collection, click the ••• button next to its entry, select **View details**, and copy the **Collection ID**. Each graph variant has its own default collection called **Default MCP Tools**. To use this default collection, specify `operations.id: default`. Apollo MCP Server automatically fetches the default collection if no ID is specified. ```yaml title="Example config file for using a GraphOS operation collection" operations: source: collection id: default ``` The MCP Server supports hot reloading of the GraphOS operation collection, so it automatically picks up changes from GraphOS without restarting. #### Setting operation collection variables When saving operation collections, remove any dynamic variables from the **Variables** panel of Explorer. This enables the LLM to modify the variables when calling the operation. Any variables set to any valid value (even `null`) in the Variables panel of a saved operation are used as a hardcoded override for that operation's variable. For example, if you create the following operation for an operation collection: ```graphql query GetProduct($productId: ID!) { product(id: $productId) { id description } } ``` And the Variables panel has `productId` set to `1234`: ```json { "productId": "1234" } ``` Then, every time the LLM calls the `GetProduct` operation, the `productId` variable is always set to `1234`. The same is true if `productId` is set to `null`. If you want to use dynamic variables that the LLM can modify, remove any variables from the Variables panel and save that operation to the collection. ### From persisted query manifests Apollo MCP Server supports reading GraphQL operations from Apollo-formatted [persisted query manifest](/graphos/platform/security/persisted-queries#manifest-format) files. Set the persisted query manifest file for the MCP Server with the `operations` option. The MCP Server supports hot reloading of persisted query manifests, so changes to manifests are applied without restarting. An example manifest is available in the [GitHub repo](https://github.com/apollographql/apollo-mcp-server/tree/main/graphql/weather/persisted_queries). ```yaml title="Example config for using persisted query manifest" operations: source: manifest path: <PATH/TO/persisted-queries-manifest.json> ``` ### From GraphOS-managed persisted queries For graphs managed by GraphOS, Apollo MCP Server can get operations by reading persisted queries from GraphOS. The MCP Server uses Apollo Uplink to access the persisted queries. To use GraphOS persisted queries, you must set your graph credentials `APOLLO_GRAPH_REF` and `APOLLO_KEY` as environment variables. Use the `operations.source: uplink` option to specify that tools should be loaded from GraphOS-managed persisted queries. <Tip> Use a [contract variant](/graphos/platform/schema-management/delivery/contracts/overview) with a persisted query list associated with that variant, so you can control what AI can consume from your graph. [Learn more](/apollo-mcp-server/best-practices#use-contract-variants-to-control-ai-access-to-graphs). </Tip> ```yaml title="Example config using GraphOS-managed persisted queries" operations: source: uplink ``` The MCP Server supports hot reloading of GraphOS-managed persisted queries, so it can automatically pick up changes from GraphOS without restarting. If you register a persisted query with a specific client name instead of `null`, you must configure the MCP Server to send the necessary header indicating the client name to the router. Use the `headers` option when running the MCP Server to pass the header to the router. The default name of the header expected by the router is `apollographql-client-name`. To use a different header name, configure `telemetry.apollo.client_name_header` in router YAML configuration. ```yaml title="Example config using GraphOS-managed persisted queries" {1-2} headers: "apollographql-client-name": "my-web-app" operations: source: uplink ``` ## Introspection tools In addition to defining specific tools for pre-defined GraphQL operations, Apollo MCP Server supports introspection tools that enable AI agents to explore the graph schema and execute operations dynamically. You can enable the following introspection tools: - `introspect`: allows the AI model to introspect the schema of the GraphQL API by providing a specific type name to get information about, and a depth parameter to determine how deep to traverse the subtype hierarchy. The AI model can start the introspection by looking up the top-level `Query` or `Mutation` type. - `search`: allows the AI model to search for type information by providing a set of search terms. This can result in fewer tool calls than `introspect`, especially if the desired type is deep in the type hierarchy of the schema. Search results include all the parent type information needed to construct operations involving the matching type. - `validate`: validates a GraphQL operation against the schema without executing it. This allows AI models to verify that their operations are syntactically correct and conform to the schema before execution, preventing unintended side effects. Operations should be validated prior to calling the `execute` tool. - `execute`: executes an operation on the GraphQL endpoint The MCP client can use these tools to provide schema information to the model and its context window, and allow the model to execute GraphQL operations based on that schema. ### Minification Both the `introspect` and `search` tools support minification of their results through the `minify` option. These options help optimize context window usage for AI models. - **Reduces context window usage**: Minified GraphQL SDL takes up significantly less space in the AI model's context window, allowing for more complex schemas or additional context - **Uses compact notation**: Type definitions use prefixed compact syntax and common scalar types are shortened - **Preserves functionality**: All essential type information is retained, just in a more compact format - **Includes legend in tool descriptions**: When minify is enabled, the tool descriptions automatically include a legend explaining the notation **Minification format:** - **Type prefixes**: `T=type`, `I=input`, `E=enum`, `U=union`, `F=interface` - **Scalar abbreviations**: `s=String`, `i=Int`, `f=Float`, `b=Boolean`, `d=ID` - **Directive abbreviations**: `@D=deprecated` - **Type modifiers**: `!=required`, `[]=list`, `<>=implements` Example comparison: **Regular output:** ```graphql type User { id: ID! name: String email: String! posts: [Post] } ``` **Minified output:** ``` T:User:id:d!,name:s,email:s!,posts:[Post] ``` <Tip> Use a [contract variant](/graphos/platform/schema-management/delivery/contracts/overview) so you can control the parts of your graph that AI can introspect. [Learn more](/apollo-mcp-server/best-practices#use-contract-variants-to-control-ai-access-to-graphs) </Tip> ```yaml title="Example config using introspection" introspection: execute: enabled: true introspect: enabled: true minify: true search: enabled: true minify: true index_memory_bytes: 50000000 leaf_depth: 1 validate: enabled: true ```