diff --git a/.changeset/eager-badgers-purr.md b/.changeset/eager-badgers-purr.md
new file mode 100644
index 000000000..a41a3f5e9
--- /dev/null
+++ b/.changeset/eager-badgers-purr.md
@@ -0,0 +1,5 @@
+---
+type: Changed
+pr: 3158
+---
+**SDK Runtime Bridge seam deepened** — dispatch is now centralized behind a native-first Runtime Bridge Module with explicit fallback policy (allowFallbackToSubprocess), strict native-only mode (strictSdk), and structured dispatch observability events; architecture/ADR docs updated to reflect the seam.