diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6e65489..f3485a5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,9 @@
 ### Changed
 - Feature flags can be overridden at runtime via `features.json` (refreshable via `query-ids`).
 
+### Fixed
+- GraphQL feature flags now include `post_ctas_fetch_enabled` to avoid 400s (#38) — thanks @philipp-spiess.
+
 ## 0.5.1 — 2026-01-01
 
 ### Changed
diff --git a/src/lib/twitter-client-features.ts b/src/lib/twitter-client-features.ts
index 18581e9..27be137 100644
--- a/src/lib/twitter-client-features.ts
+++ b/src/lib/twitter-client-features.ts
@@ -17,6 +17,7 @@ export function buildArticleFeatures(): Record<string, boolean> {
     responsive_web_grok_analyze_post_followups_enabled: false,
     responsive_web_grok_annotations_enabled: false,
     responsive_web_jetfuel_frame: true,
+    post_ctas_fetch_enabled: true,
     responsive_web_grok_share_attachment_enabled: true,
     articles_preview_enabled: true,
     responsive_web_edit_tweet_api_enabled: true,
@@ -86,6 +87,7 @@ export function buildSearchFeatures(): Record<string, boolean> {
     responsive_web_grok_analyze_post_followups_enabled: false,
     responsive_web_grok_annotations_enabled: false,
     responsive_web_jetfuel_frame: true,
+    post_ctas_fetch_enabled: true,
     responsive_web_grok_share_attachment_enabled: true,
     responsive_web_edit_tweet_api_enabled: true,
     graphql_is_translatable_rweb_tweet_is_translatable_enabled: true,
@@ -121,6 +123,7 @@ export function buildTweetCreateFeatures(): Record<string, boolean> {
     responsive_web_grok_analyze_post_followups_enabled: false,
     responsive_web_grok_annotations_enabled: false,
     responsive_web_jetfuel_frame: true,
+    post_ctas_fetch_enabled: true,
     responsive_web_grok_share_attachment_enabled: true,
     responsive_web_edit_tweet_api_enabled: true,
     graphql_is_translatable_rweb_tweet_is_translatable_enabled: true,
@@ -192,6 +195,7 @@ export function buildListsFeatures(): Record<string, boolean> {
     responsive_web_grok_analyze_post_followups_enabled: false,
     responsive_web_grok_annotations_enabled: false,
     responsive_web_jetfuel_frame: true,
+    post_ctas_fetch_enabled: true,
     responsive_web_grok_share_attachment_enabled: true,
     articles_preview_enabled: true,
     responsive_web_edit_tweet_api_enabled: true,
@@ -232,6 +236,7 @@ export function buildFollowingFeatures(): Record<string, boolean> {
     responsive_web_grok_analyze_post_followups_enabled: false,
     responsive_web_grok_annotations_enabled: false,
     responsive_web_jetfuel_frame: false,
+    post_ctas_fetch_enabled: true,
     responsive_web_grok_share_attachment_enabled: false,
     articles_preview_enabled: true,
     responsive_web_edit_tweet_api_enabled: true,