fix(ai): skip unknown bedrock content blocks

closes #4223

packages/ai/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- Fixed Amazon Bedrock message conversion to skip unknown content blocks instead of failing the stream ([#4223](https://github.com/earendil-works/pi/issues/4223)).
 - Fixed Azure OpenAI Responses and OpenAI Responses error formatting to prefix HTTP status codes onto `errorMessage`, so transient 5xx and 429 errors are correctly matched by the agent-level auto-retry classifier ([#4232](https://github.com/earendil-works/pi/issues/4232)).
 - Fixed Xiaomi MiMo model metadata to use the OpenAI-compatible endpoints and `openai-completions` API, restoring multi-turn thinking/tool-call sessions ([#4505](https://github.com/earendil-works/pi/issues/4505)).
 - Fixed OpenCode Go Kimi reasoning replay by normalizing streamed `reasoning` fields back to `reasoning_content` for OpenCode Go only ([#4251](https://github.com/earendil-works/pi/issues/4251)).

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

@@ -618,24 +618,31 @@ function convertMessages(
 		const m = transformedMessages[i];
 
 		switch (m.role) {
-			case "user":
+			case "user": {
+				const content: ContentBlock[] = [];
+				if (typeof m.content === "string") {
+					content.push({ text: sanitizeSurrogates(m.content) });
+				} else {
+					for (const c of m.content) {
+						switch (c.type) {
+							case "text":
+								content.push({ text: sanitizeSurrogates(c.text) });
+								break;
+							case "image":
+								content.push({ image: createImageBlock(c.mimeType, c.data) });
+								break;
+							default:
+								continue;
+						}
+					}
+				}
+				if (content.length === 0) continue;
 				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");
-									}
-								}),
+					content,
 				});
 				break;
+			}
 			case "assistant": {
 				// Skip assistant messages with empty content (e.g., from aborted requests)
 				// Bedrock rejects messages with empty content arrays
@@ -686,7 +693,7 @@ function convertMessages(
 							}
 							break;
 						default:
-							throw new Error("Unknown assistant content type");
+							continue;
 					}
 				}
 				// Skip if all content blocks were filtered out
@@ -745,7 +752,7 @@ function convertMessages(
 				break;
 			}
 			default:
-				throw new Error("Unknown message role");
+				continue;
 		}
 	}
 

packages/ai/test/bedrock-convert-messages.test.ts

@@ -0,0 +1,159 @@
+import { describe, expect, it, vi } from "vitest";
+
+const bedrockMock = vi.hoisted(() => ({
+	constructorCalls: [] as Array<Record<string, unknown>>,
+}));
+
+vi.mock("@aws-sdk/client-bedrock-runtime", () => {
+	class BedrockRuntimeServiceException extends Error {}
+
+	class BedrockRuntimeClient {
+		constructor(config: Record<string, unknown>) {
+			bedrockMock.constructorCalls.push(config);
+		}
+
+		send(): Promise<never> {
+			return Promise.reject(new Error("mock send"));
+		}
+	}
+
+	class ConverseStreamCommand {
+		readonly input: unknown;
+
+		constructor(input: unknown) {
+			this.input = input;
+		}
+	}
+
+	return {
+		BedrockRuntimeClient,
+		BedrockRuntimeServiceException,
+		ConverseStreamCommand,
+		StopReason: {
+			END_TURN: "end_turn",
+			STOP_SEQUENCE: "stop_sequence",
+			MAX_TOKENS: "max_tokens",
+			MODEL_CONTEXT_WINDOW_EXCEEDED: "model_context_window_exceeded",
+			TOOL_USE: "tool_use",
+		},
+		CachePointType: { DEFAULT: "default" },
+		CacheTTL: { ONE_HOUR: "ONE_HOUR" },
+		ConversationRole: { ASSISTANT: "assistant", USER: "user" },
+		ImageFormat: { JPEG: "jpeg", PNG: "png", GIF: "gif", WEBP: "webp" },
+		ToolResultStatus: { ERROR: "error", SUCCESS: "success" },
+	};
+});
+
+import { getModel } from "../src/models.js";
+import { streamBedrock } from "../src/providers/amazon-bedrock.js";
+import type { Context, Message } from "../src/types.js";
+
+const baseModel = getModel("amazon-bedrock", "us.anthropic.claude-sonnet-4-5-20250929-v1:0");
+
+async function capturePayload(context: Context): Promise<unknown> {
+	let capturedPayload: unknown;
+	const s = streamBedrock(baseModel, context, {
+		cacheRetention: "none",
+		signal: AbortSignal.abort(),
+		onPayload: (payload) => {
+			capturedPayload = payload;
+			return payload;
+		},
+	});
+	for await (const event of s) {
+		if (event.type === "error") break;
+	}
+	return capturedPayload;
+}
+
+describe("bedrock convertMessages skips unknown content types", () => {
+	it("skips unknown user content blocks instead of throwing", async () => {
+		const messages: Message[] = [
+			{
+				role: "user",
+				content: [
+					{ type: "text", text: "hello" },
+					{ type: "unknown", data: "foo" },
+				] as any,
+				timestamp: Date.now(),
+			},
+		];
+		const payload = await capturePayload({ messages });
+		expect(payload).toBeDefined();
+		const p = payload as { messages: Array<{ role: string; content: unknown[] }> };
+		expect(p.messages).toHaveLength(1);
+		expect(p.messages[0].content).toHaveLength(1);
+		expect(p.messages[0].content[0]).toEqual({ text: "hello" });
+	});
+
+	it("skips unknown assistant content blocks instead of throwing", async () => {
+		const messages: Message[] = [
+			{
+				role: "assistant",
+				content: [
+					{ type: "text", text: "hello" },
+					{ type: "unknown", data: "foo" },
+				] as any,
+				api: "bedrock-converse-stream",
+				provider: "amazon-bedrock",
+				model: baseModel.id,
+				usage: {
+					input: 0,
+					output: 0,
+					cacheRead: 0,
+					cacheWrite: 0,
+					totalTokens: 0,
+					cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+				},
+				stopReason: "stop",
+				timestamp: Date.now(),
+			},
+		];
+		const payload = await capturePayload({ messages });
+		expect(payload).toBeDefined();
+		const p = payload as { messages: Array<{ role: string; content: unknown[] }> };
+		expect(p.messages).toHaveLength(1);
+		expect(p.messages[0].content).toHaveLength(1);
+		expect(p.messages[0].content[0]).toEqual({ text: "hello" });
+	});
+
+	it("skips user messages with only unknown content blocks", async () => {
+		const messages: Message[] = [
+			{
+				role: "user",
+				content: [{ type: "unknown", data: "foo" }] as any,
+				timestamp: Date.now(),
+			},
+		];
+		const payload = await capturePayload({ messages });
+		expect(payload).toBeDefined();
+		const p = payload as { messages: Array<{ role: string; content: unknown[] }> };
+		expect(p.messages).toHaveLength(0);
+	});
+
+	it("skips assistant messages with only unknown content blocks", async () => {
+		const messages: Message[] = [
+			{
+				role: "assistant",
+				content: [{ type: "unknown", data: "foo" }] as any,
+				api: "bedrock-converse-stream",
+				provider: "amazon-bedrock",
+				model: baseModel.id,
+				usage: {
+					input: 0,
+					output: 0,
+					cacheRead: 0,
+					cacheWrite: 0,
+					totalTokens: 0,
+					cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+				},
+				stopReason: "stop",
+				timestamp: Date.now(),
+			},
+		];
+		const payload = await capturePayload({ messages });
+		expect(payload).toBeDefined();
+		const p = payload as { messages: Array<{ role: string; content: unknown[] }> };
+		expect(p.messages).toHaveLength(0);
+	});
+});