diff --git a/public/openapi/write/categories/cid/follow.yaml b/public/openapi/write/categories/cid/follow.yaml
index cd8f8a0b96..4f54974d60 100644
--- a/public/openapi/write/categories/cid/follow.yaml
+++ b/public/openapi/write/categories/cid/follow.yaml
@@ -26,7 +26,7 @@ put:
             actor:
               type: string
               description: A valid actor uri or webfinger handle
-              example: 'foobar@example.org'
+              example: 'https://example.org/foobar'
   responses:
     '200':
       description: successfully sent category synchronization request
@@ -69,7 +69,7 @@ delete:
             actor:
               type: string
               description: A valid actor uri or webfinger handle
-              example: 'foobar@example.org'
+              example: 'https://example.org/foobar'
   responses:
     '200':
       description: successfully unsynchronized category
diff --git a/test/api.js b/test/api.js
index 857a5f8799..7575456863 100644
--- a/test/api.js
+++ b/test/api.js
@@ -23,6 +23,7 @@ const posts = require('../src/posts');
 const plugins = require('../src/plugins');
 const flags = require('../src/flags');
 const messaging = require('../src/messaging');
+const activitypub = require('../src/activitypub');
 const utils = require('../src/utils');
 const api = require('../src/api');
 
@@ -317,6 +318,13 @@ describe('API', async () => {
 		// Retrieve CSRF token using cookie, to test Write API
 		csrfToken = await helpers.getCsrfToken(jar);
 
+		// Pre-seed ActivityPub cache so contrived actor assertions pass
+		activitypub._cache.set(`0;https://example.org/foobar`, {
+			id: 'https://example.org/foobar',
+			name: 'foobar',
+			publicKey: 'secretcat',
+		});
+
 		setup = true;
 	}