diff --git a/.changeset/quiet-doors-eat.md b/.changeset/quiet-doors-eat.md
new file mode 100644
index 0000000000..587dba8ba7
--- /dev/null
+++ b/.changeset/quiet-doors-eat.md
@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Fixes a case where `defineAction` autocomplete for the `accept` prop would not show `"form"` as a possible value
diff --git a/packages/astro/src/actions/runtime/virtual/server.ts b/packages/astro/src/actions/runtime/virtual/server.ts
index ce4d5f6966..d52a284ce3 100644
--- a/packages/astro/src/actions/runtime/virtual/server.ts
+++ b/packages/astro/src/actions/runtime/virtual/server.ts
@@ -50,7 +50,7 @@ export type ActionClient<
 
 export function defineAction<
 	TOutput,
-	TAccept extends Accept = 'json',
+	TAccept extends Accept,
 	TInputSchema extends InputSchema<Accept> | undefined = TAccept extends 'form'
 		? // If `input` is omitted, default to `FormData` for forms and `any` for JSON.
 			z.ZodType<FormData>