diff --git a/docs/CLAUDE.dist.md b/docs/CLAUDE.dist.md
index 4078b5ca6..36b1c11df 100644
--- a/docs/CLAUDE.dist.md
+++ b/docs/CLAUDE.dist.md
@@ -1070,6 +1070,8 @@ Screenshot presets: mobile, iphone-mobile, tablet, desktop-small, desktop-medium
 
 Use this instead of manually browsing, especially for SPA pages and Ajax-heavy features.
 
+**CRITICAL: SPA routes ARE server routes.** The server knows all SPA routes. `rsx:debug` uses Playwright to fully render pages including all JavaScript and SPA navigation. If you get a 404, the route genuinely doesn't exist - check your URL pattern and route definitions. Never dismiss 404s as "SPA routes can't be tested server-side" - this analysis is incorrect.
+
 ### Debugging
 
 - **rsx_dump_die()** - Debug output