diff --git a/.changeset/brown-bulldogs-share.md b/.changeset/brown-bulldogs-share.md
new file mode 100644
index 000000000000..c8cadb11b28c
--- /dev/null
+++ b/.changeset/brown-bulldogs-share.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes an issue where an incorrect usage of Astro actions was lost when porting the fix from v4 to v5
diff --git a/packages/astro/src/actions/runtime/virtual/server.ts b/packages/astro/src/actions/runtime/virtual/server.ts
index f28b3c2393b9..47decf18e5d4 100644
--- a/packages/astro/src/actions/runtime/virtual/server.ts
+++ b/packages/astro/src/actions/runtime/virtual/server.ts
@@ -4,11 +4,13 @@ import { AstroError } from '../../../core/errors/errors.js';
 import type { APIContext } from '../../../types/public/index.js';
 import { ACTION_RPC_ROUTE_PATTERN } from '../../consts.js';
 import {
+	ACTION_API_CONTEXT_SYMBOL,
 	type ActionAPIContext,
 	type ErrorInferenceObject,
 	type MaybePromise,
 	formContentTypes,
 	hasContentType,
+	isActionAPIContext,
 } from '../utils.js';
 import type { Locals } from '../utils.js';
 import { getAction } from './get-action.js';
@@ -79,7 +81,8 @@ export function defineAction<
 			: getJsonServerHandler(handler, inputSchema);
 
 	async function safeServerHandler(this: ActionAPIContext, unparsedInput: unknown) {
-		if (typeof this === 'function') {
+		// The ActionAPIContext should always contain the `params` property
+		if (typeof this === 'function' || !isActionAPIContext(this)) {
 			throw new AstroError(ActionCalledFromServerError);
 		}
 		return callSafely(() => serverHandler(unparsedInput, this));
@@ -293,6 +296,7 @@ export function getActionContext(context: APIContext): ActionMiddlewareContext {
 					redirect: _redirect,
 					...actionAPIContext
 				} = context;
+				Reflect.set(actionAPIContext, ACTION_API_CONTEXT_SYMBOL, true);
 				const handler = baseAction.bind(actionAPIContext satisfies ActionAPIContext);
 				return handler(input);
 			},
diff --git a/packages/astro/src/actions/utils.ts b/packages/astro/src/actions/utils.ts
index dc0fa4b1486e..b6fe63f6caca 100644
--- a/packages/astro/src/actions/utils.ts
+++ b/packages/astro/src/actions/utils.ts
@@ -1,7 +1,7 @@
 import type fsMod from 'node:fs';
 import * as eslexer from 'es-module-lexer';
 import type { APIContext } from '../types/public/context.js';
-import type { ActionAPIContext, Locals } from './runtime/utils.js';
+import { ACTION_API_CONTEXT_SYMBOL, type ActionAPIContext, type Locals } from './runtime/utils.js';
 import { deserializeActionResult, getActionQueryString } from './runtime/virtual/shared.js';
 
 export function hasActionPayload(locals: APIContext['locals']): locals is Locals {
@@ -22,6 +22,7 @@ export function createGetActionResult(locals: APIContext['locals']): APIContext[
 
 export function createCallAction(context: ActionAPIContext): APIContext['callAction'] {
 	return (baseAction, input) => {
+		Reflect.set(context, ACTION_API_CONTEXT_SYMBOL, true);
 		const action = baseAction.bind(context);
 		return action(input) as any;
 	};
diff --git a/packages/astro/test/fixtures/actions/src/pages/invalid.astro b/packages/astro/test/fixtures/actions/src/pages/invalid.astro
index 908eee853bd4..fe152dbba0a7 100644
--- a/packages/astro/test/fixtures/actions/src/pages/invalid.astro
+++ b/packages/astro/test/fixtures/actions/src/pages/invalid.astro
@@ -2,5 +2,5 @@
 import { actions } from "astro:actions";
 
 // this is invalid, it should fail
-const result = await actions.imageUploadInChunks();
+const result = await actions.subscribe({ channel: "hey" });
 ---