fix(ai): filtered empty user messages across all providers

packages/ai/CHANGELOG.md

@@ -1,6 +1,14 @@
 # Changelog
 
 ## [Unreleased]
+### Fixed
+
+- Fixed API validation errors when sending empty user messages (resume with `.`) across all providers:
+  - Google Cloud Code Assist (google-shared.ts)
+  - OpenAI Responses API (openai-responses.ts)
+  - OpenAI Codex Responses API (openai-codex-responses.ts)
+  - Cursor (cursor.ts)
+  - Amazon Bedrock (amazon-bedrock.ts)
 
 ## [6.9.69] - 2026-01-21
 ### Added

packages/ai/src/providers/amazon-bedrock.ts

@@ -342,22 +342,39 @@ function convertMessages(context: Context, model: Model<"bedrock-converse-stream
 
 		switch (m.role) {
 			case "user":
-				result.push({
-					role: ConversationRole.USER,
-					content:
-						typeof m.content === "string"
-							? [{ text: sanitizeSurrogates(m.content) }]
-							: m.content.map((c) => {
-									switch (c.type) {
-										case "text":
-											return { text: sanitizeSurrogates(c.text) };
-										case "image":
-											return { image: createImageBlock(c.mimeType, c.data) };
-										default:
-											throw new Error("Unknown user content type");
-									}
-								}),
-				});
+				if (typeof m.content === "string") {
+					// Skip empty user messages
+					if (!m.content || m.content.trim() === "") continue;
+					result.push({
+						role: ConversationRole.USER,
+						content: [{ text: sanitizeSurrogates(m.content) }],
+					});
+				} else {
+					const contentBlocks = m.content
+						.map((c) => {
+							switch (c.type) {
+								case "text":
+									return { text: sanitizeSurrogates(c.text) };
+								case "image":
+									return { image: createImageBlock(c.mimeType, c.data) };
+								default:
+									throw new Error("Unknown user content type");
+							}
+						})
+						.filter((block) => {
+							// Filter out empty text blocks
+							if ("text" in block && block.text) {
+								return block.text.trim().length > 0;
+							}
+							return true; // Keep non-text blocks (images)
+						});
+					// Skip message if all blocks filtered out
+					if (contentBlocks.length === 0) continue;
+					result.push({
+						role: ConversationRole.USER,
+						content: contentBlocks,
+					});
+				}
 				break;
 			case "assistant": {
 				// Skip assistant messages with empty content (e.g., from aborted requests)

packages/ai/src/providers/cursor.ts

@@ -1838,11 +1838,12 @@ function buildMcpToolDefinitions(tools: Tool[] | undefined): McpToolDefinition[]
 function extractUserMessageText(msg: Message): string {
 	if (msg.role !== "user") return "";
 	const content = msg.content;
-	if (typeof content === "string") return content;
-	return content
+	if (typeof content === "string") return content.trim();
+	const text = content
 		.filter((c): c is TextContent => c.type === "text")
 		.map((c) => c.text)
 		.join("\n");
+	return text.trim();
 }
 
 /**
@@ -1891,7 +1892,7 @@ function buildConversationTurns(messages: Message[]): Uint8Array[] {
 
 		// Create and serialize user message
 		const userText = extractUserMessageText(msg);
-		if (!userText) {
+		if (!userText || userText.length === 0) {
 			i++;
 			continue;
 		}
@@ -1982,10 +1983,15 @@ function buildGrpcRequest(
 	const userText =
 		lastMessage?.role === "user"
 			? typeof lastMessage.content === "string"
-				? lastMessage.content
+				? lastMessage.content.trim()
 				: extractText(lastMessage.content)
 			: "";
 
+	// Validate that we have non-empty user text for the action
+	if (!userText || userText.trim().length === 0) {
+		throw new Error("Cannot send empty user message to Cursor API");
+	}
+
 	const userMessage = create(UserMessageSchema, {
 		text: userText,
 		messageId: crypto.randomUUID(),

packages/ai/src/providers/google-shared.ts

@@ -79,6 +79,8 @@ export function convertMessages<T extends GoogleApiType>(model: Model<T>, contex
 	for (const msg of transformedMessages) {
 		if (msg.role === "user") {
 			if (typeof msg.content === "string") {
+				// Skip empty user messages
+				if (!msg.content || msg.content.trim() === "") continue;
 				contents.push({
 					role: "user",
 					parts: [{ text: sanitizeSurrogates(msg.content) }],
@@ -96,7 +98,14 @@ export function convertMessages<T extends GoogleApiType>(model: Model<T>, contex
 						};
 					}
 				});
-				const filteredParts = !model.input.includes("image") ? parts.filter((p) => p.text !== undefined) : parts;
+				// Filter out images if model doesn't support them, and empty text blocks
+				let filteredParts = !model.input.includes("image") ? parts.filter((p) => p.text !== undefined) : parts;
+				filteredParts = filteredParts.filter((p) => {
+					if (p.text !== undefined) {
+						return p.text.trim().length > 0;
+					}
+					return true; // Keep non-text parts (images)
+				});
 				if (filteredParts.length === 0) continue;
 				contents.push({
 					role: "user",

packages/ai/src/providers/openai-codex-responses.ts

@@ -571,6 +571,8 @@ function convertMessages(model: Model<"openai-codex-responses">, context: Contex
 	for (const msg of transformedMessages) {
 		if (msg.role === "user") {
 			if (typeof msg.content === "string") {
+				// Skip empty user messages
+				if (!msg.content || msg.content.trim() === "") continue;
 				messages.push({
 					role: "user",
 					content: [{ type: "input_text", text: sanitizeSurrogates(msg.content) }],
@@ -589,9 +591,16 @@ function convertMessages(model: Model<"openai-codex-responses">, context: Contex
 						image_url: `data:${item.mimeType};base64,${item.data}`,
 					} satisfies ResponseInputImage;
 				});
-				const filteredContent = !model.input.includes("image")
+				// Filter out images if model doesn't support them, and empty text blocks
+				let filteredContent = !model.input.includes("image")
 					? content.filter((c) => c.type !== "input_image")
 					: content;
+				filteredContent = filteredContent.filter((c) => {
+					if (c.type === "input_text") {
+						return c.text.trim().length > 0;
+					}
+					return true; // Keep non-text content (images)
+				});
 				if (filteredContent.length === 0) continue;
 				messages.push({
 					role: "user",

packages/ai/src/providers/openai-responses.ts

@@ -468,6 +468,8 @@ function convertMessages(
 	for (const msg of transformedMessages) {
 		if (msg.role === "user") {
 			if (typeof msg.content === "string") {
+				// Skip empty user messages
+				if (!msg.content || msg.content.trim() === "") continue;
 				messages.push({
 					role: "user",
 					content: [{ type: "input_text", text: sanitizeSurrogates(msg.content) }],
@@ -487,9 +489,16 @@ function convertMessages(
 						} satisfies ResponseInputImage;
 					}
 				});
-				const filteredContent = !model.input.includes("image")
+				// Filter out images if model doesn't support them, and empty text blocks
+				let filteredContent = !model.input.includes("image")
 					? content.filter((c) => c.type !== "input_image")
 					: content;
+				filteredContent = filteredContent.filter((c) => {
+					if (c.type === "input_text") {
+						return c.text.trim().length > 0;
+					}
+					return true; // Keep non-text content (images)
+				});
 				if (filteredContent.length === 0) continue;
 				messages.push({
 					role: "user",