diff --git a/src/mapeo-project.js b/src/mapeo-project.js
index ab50f2e26..a820d2c1a 100644
--- a/src/mapeo-project.js
+++ b/src/mapeo-project.js
@@ -51,7 +51,7 @@ import { IconApi } from './icon-api.js'
 import { readConfig } from './config-import.js'
 import TranslationApi from './translation-api.js'
 /** @import { ProjectSettingsValue } from '@comapeo/schema' */
-/** @import { CoreStorage, KeyPair, Namespace } from './types.js' */
+/** @import { CoreStorage, KeyPair, Namespace, ReplicationStream } from './types.js' */
 
 /** @typedef {Omit<ProjectSettingsValue, 'schemaName'>} EditableProjectSettings */
 /** @typedef {ProjectSettingsValue['configMetadata']} ConfigMetadata */
@@ -581,20 +581,30 @@ export class MapeoProject extends TypedEmitter {
    * and only this project will replicate (to replicate multiple projects you
    * need to replicate the manager instance via manager[kManagerReplicate])
    *
-   * @param {Parameters<import('hypercore')['replicate']>[0]} stream A duplex stream, a @hyperswarm/secret-stream, or a Protomux instance
+   * @param {(
+   *   boolean |
+   *   import('stream').Duplex |
+   *   import('streamx').Duplex
+   * )} isInitiatorOrStream
+   * @returns {ReplicationStream}
    */
-  [kProjectReplicate](stream) {
-    // @ts-expect-error - hypercore types need updating
-    const replicationStream = this.#coreManager.creatorCore.replicate(stream, {
-      // @ts-ignore - hypercore types do not currently include this option
-      ondiscoverykey: async (discoveryKey) => {
-        const protomux =
-          /** @type {import('protomux')<import('@hyperswarm/secret-stream')>} */ (
-            replicationStream.noiseStream.userData
-          )
-        this.#syncApi[kHandleDiscoveryKey](discoveryKey, protomux)
-      },
-    })
+  [kProjectReplicate](isInitiatorOrStream) {
+    const replicationStream = this.#coreManager.creatorCore.replicate(
+      isInitiatorOrStream,
+      /**
+       * Hypercore types need updating.
+       * @type {any}
+       */ ({
+        /** @param {Buffer} discoveryKey */
+        ondiscoverykey: async (discoveryKey) => {
+          const protomux =
+            /** @type {import('protomux')<import('@hyperswarm/secret-stream')>} */ (
+              replicationStream.noiseStream.userData
+            )
+          this.#syncApi[kHandleDiscoveryKey](discoveryKey, protomux)
+        },
+      })
+    )
     return replicationStream
   }