diff --git a/README.md b/README.md
index c19b73e..63cd98a 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,14 @@ Currently to do:
 - [X] Sandboxing the image rendering
 - [X] Prometheus-format metrics
 
+## Spec Compliance
+
+This project is designed to match the upstream [specification](https://github.com/misskey-dev/media-proxy/blob/master/SPECIFICATION.md), however a few deviations are made:
+
+- We will not honor remote `Content-Disposition` headers but instead reply with the actual filename in the request URL.
+- Remote `Content-Type` headers will only be used as a hint rather than authoritative, and resniffing is unconditionally performed.
+- SVG rasterization is planned to be removed from the proxy in favor of sanitization and CSP enforcement.
+
 ## Demo
 
 ### Avatar resizing