diff --git a/types/graphql/subscription/subscribe.d.ts b/types/graphql/subscription/subscribe.d.ts
index c4eec87ac9..a9fe6b565e 100644
--- a/types/graphql/subscription/subscribe.d.ts
+++ b/types/graphql/subscription/subscribe.d.ts
@@ -3,27 +3,72 @@ import { DocumentNode } from "../language/ast";
 import { GraphQLFieldResolver } from "../type/definition";
 import { ExecutionResult } from "../execution/execute";
 
+/**
+ * Implements the "Subscribe" algorithm described in the GraphQL specification.
+ *
+ * Returns a Promise which resolves to either an AsyncIterator (if successful)
+ * or an ExecutionResult (client error). The promise will be rejected if a
+ * server error occurs.
+ *
+ * If the client-provided arguments to this function do not result in a
+ * compliant subscription, a GraphQL Response (ExecutionResult) with
+ * descriptive errors and no data will be returned.
+ *
+ * If the the source stream could not be created due to faulty subscription
+ * resolver logic or underlying systems, the promise will resolve to a single
+ * ExecutionResult containing `errors` and no `data`.
+ *
+ * If the operation succeeded, the promise resolves to an AsyncIterator, which
+ * yields a stream of ExecutionResults representing the response stream.
+ *
+ * Accepts either an object with named arguments, or individual arguments.
+ */
+export function subscribe(args: {
+    schema: GraphQLSchema;
+    document: DocumentNode;
+    rootValue?: any;
+    contextValue?: any;
+    variableValues?: { [key: string]: any } | void;
+    operationName?: string | void;
+    fieldResolver?: GraphQLFieldResolver<any, any> | void;
+    subscribeFieldResolver?: GraphQLFieldResolver<any, any> | void;
+}): Promise<AsyncIterator<ExecutionResult> | ExecutionResult>;
+
 export function subscribe(
     schema: GraphQLSchema,
     document: DocumentNode,
     rootValue?: any,
     contextValue?: any,
-    variableValues?: {
-        [key: string]: any;
-    },
-    operationName?: string,
-    fieldResolver?: GraphQLFieldResolver<any, any>,
-    subscribeFieldResolver?: GraphQLFieldResolver<any, any>
+    variableValues?: { [key: string]: any } | void,
+    operationName?: string | void,
+    fieldResolver?: GraphQLFieldResolver<any, any> | void,
+    subscribeFieldResolver?: GraphQLFieldResolver<any, any> | void
 ): Promise<AsyncIterator<ExecutionResult> | ExecutionResult>;
 
+/**
+ * Implements the "CreateSourceEventStream" algorithm described in the
+ * GraphQL specification, resolving the subscription source event stream.
+ *
+ * Returns a Promise<AsyncIterable>.
+ *
+ * If the client-provided invalid arguments, the source stream could not be
+ * created, or the resolver did not return an AsyncIterable, this function will
+ * will throw an error, which should be caught and handled by the caller.
+ *
+ * A Source Event Stream represents a sequence of events, each of which triggers
+ * a GraphQL execution for that event.
+ *
+ * This may be useful when hosting the stateful subscription service in a
+ * different process or machine than the stateless GraphQL execution engine,
+ * or otherwise separating these two steps. For more on this, see the
+ * "Supporting Subscriptions at Scale" information in the GraphQL specification.
+ */
 export function createSourceEventStream(
     schema: GraphQLSchema,
     document: DocumentNode,
     rootValue?: any,
     contextValue?: any,
-    variableValues?: {
-        [key: string]: any;
-    },
-    operationName?: string,
-    fieldResolver?: GraphQLFieldResolver<any, any>
-): Promise<AsyncIterable<any>>;
+    variableValues?: { [key: string]: any },
+    operationName?: string | void,
+    fieldResolver?: GraphQLFieldResolver<any, any> | void
+): Promise<AsyncIterable<any> | ExecutionResult>;