fix(ai): ignore unknown anthropic sse events

closes #3708

packages/ai/CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Fixed
 
+- Fixed Anthropic SSE parsing to ignore unknown proxy events such as OpenAI-style `done` terminators ([#3708](https://github.com/badlogic/pi-mono/issues/3708)).
 - Fixed OpenAI-compatible prompt cache tests to cover proxies that explicitly disable long cache retention.
 - Stopped sending `tools: []` on OpenAI-compatible, Anthropic, OpenAI Responses, OpenAI Codex Responses, and Azure OpenAI Responses requests when no tools are active (e.g. `pi --no-tools`). DashScope/Aliyun Qwen (OpenAI-compatible) rejects empty tools arrays with `"[] is too short - 'tools'"` (HTTP 400); the field is now omitted unless the conversation has tool history (the existing LiteLLM/Anthropic-proxy workaround).
 - Fixed `supportsXhigh()` to recognize DeepSeek V4 Pro, preserving `xhigh` reasoning requests so they map to DeepSeek's `max` effort ([#3662](https://github.com/badlogic/pi-mono/issues/3662))

packages/ai/src/providers/anthropic.ts

@@ -237,6 +237,15 @@ interface SseDecoderState {
 	raw: string[];
 }
 
+const ANTHROPIC_MESSAGE_EVENTS: ReadonlySet<string> = new Set([
+	"message_start",
+	"message_delta",
+	"message_stop",
+	"content_block_start",
+	"content_block_delta",
+	"content_block_stop",
+]);
+
 function flushSseEvent(state: SseDecoderState): ServerSentEvent | null {
 	if (!state.event && state.data.length === 0) {
 		return null;
@@ -376,14 +385,14 @@ async function* iterateAnthropicEvents(
 	}
 
 	for await (const sse of iterateSseMessages(response.body, signal)) {
-		if (!sse.event || sse.event === "ping") {
-			continue;
-		}
-
 		if (sse.event === "error") {
 			throw new Error(sse.data);
 		}
 
+		if (!ANTHROPIC_MESSAGE_EVENTS.has(sse.event ?? "")) {
+			continue;
+		}
+
 		try {
 			yield parseJsonWithRepair<RawMessageStreamEvent>(sse.data);
 		} catch (error) {

packages/ai/test/anthropic-sse-parsing.test.ts

@@ -13,6 +13,61 @@ function createSseResponse(events: Array<{ event: string; data: string }>): Resp
 	});
 }
 
+const minimalAnthropicEvents = [
+	{
+		event: "message_start",
+		data: JSON.stringify({
+			type: "message_start",
+			message: {
+				id: "msg_test",
+				usage: {
+					input_tokens: 12,
+					output_tokens: 0,
+					cache_read_input_tokens: 0,
+					cache_creation_input_tokens: 0,
+				},
+			},
+		}),
+	},
+	{
+		event: "content_block_start",
+		data: JSON.stringify({
+			type: "content_block_start",
+			index: 0,
+			content_block: { type: "text", text: "" },
+		}),
+	},
+	{
+		event: "content_block_delta",
+		data: JSON.stringify({
+			type: "content_block_delta",
+			index: 0,
+			delta: { type: "text_delta", text: "Hello" },
+		}),
+	},
+	{
+		event: "content_block_stop",
+		data: JSON.stringify({ type: "content_block_stop", index: 0 }),
+	},
+	{
+		event: "message_delta",
+		data: JSON.stringify({
+			type: "message_delta",
+			delta: { stop_reason: "end_turn" },
+			usage: {
+				input_tokens: 12,
+				output_tokens: 5,
+				cache_read_input_tokens: 0,
+				cache_creation_input_tokens: 0,
+			},
+		}),
+	},
+	{
+		event: "message_stop",
+		data: JSON.stringify({ type: "message_stop" }),
+	},
+];
+
 function createFakeAnthropicClient(response: Response): Anthropic {
 	return {
 		messages: {
@@ -110,4 +165,25 @@ describe("Anthropic raw SSE parsing", () => {
 			text: "col1\tcol2",
 		});
 	});
+
+	it("ignores unknown SSE events after message_stop", async () => {
+		const model = getModel("anthropic", "claude-haiku-4-5");
+		const context: Context = {
+			messages: [{ role: "user", content: "Say hello.", timestamp: Date.now() }],
+		};
+		const response = createSseResponse([
+			...minimalAnthropicEvents,
+			{ event: "done", data: "[DONE]" },
+			{ event: "proxy.stats", data: "not json" },
+		]);
+
+		const stream = streamAnthropic(model, context, {
+			client: createFakeAnthropicClient(response),
+		});
+		const result = await stream.result();
+
+		expect(result.stopReason).toBe("stop");
+		expect(result.errorMessage).toBeUndefined();
+		expect(result.content).toEqual([{ type: "text", text: "Hello" }]);
+	});
 });

packages/ai/test/anthropic-tool-name-normalization.test.ts

@@ -24,7 +24,7 @@ const oauthToken = await resolveApiKey("anthropic");
  * - Result: tool call has name "Glob" but no tool exists with that name
  */
 describe.skipIf(!oauthToken)("Anthropic OAuth tool name normalization", () => {
-	const model = getModel("anthropic", "claude-sonnet-4-20250514");
+	const model = getModel("anthropic", "claude-sonnet-4-6");
 
 	it("should normalize user-defined tool matching CC name (todowrite -> TodoWrite -> todowrite)", async () => {
 		// User defines a tool named "todowrite" (lowercase)

packages/ai/test/context-overflow.test.ts

@@ -113,7 +113,7 @@ describe("Context overflow error handling", () => {
 
 	describe.skipIf(!process.env.ANTHROPIC_OAUTH_TOKEN)("Anthropic (OAuth)", () => {
 		it("claude-sonnet-4 - should detect overflow via isContextOverflow", async () => {
-			const model = getModel("anthropic", "claude-sonnet-4-20250514");
+			const model = getModel("anthropic", "claude-sonnet-4-6");
 			const result = await testContextOverflow(model, process.env.ANTHROPIC_OAUTH_TOKEN!);
 			logResult(result);
 

packages/ai/test/google-shared-gemini3-unsigned-tool-call.test.ts

@@ -39,7 +39,7 @@ describe("google-shared convertMessages — Gemini 3 unsigned tool calls", () =>
 					],
 					api: "google-gemini-cli",
 					provider: "google-antigravity",
-					model: "claude-sonnet-4-20250514",
+					model: "claude-sonnet-4-6",
 					usage: {
 						input: 0,
 						output: 0,
@@ -146,7 +146,7 @@ describe("google-shared convertMessages — Gemini 3 unsigned tool calls", () =>
 					],
 					api: "google-gemini-cli",
 					provider: "google-antigravity",
-					model: "claude-sonnet-4-20250514",
+					model: "claude-sonnet-4-6",
 					usage: {
 						input: 0,
 						output: 0,

packages/ai/test/lazy-module-load.test.ts

@@ -72,7 +72,7 @@ describe("lazy provider module loading", () => {
 	it("loads only the Anthropic SDK when calling the root lazy wrapper", () => {
 		const result = runProbe(`
 			const model = {
-				id: "claude-sonnet-4-20250514",
+				id: "claude-sonnet-4-6",
 				name: "Claude Sonnet 4",
 				api: "anthropic-messages",
 				provider: "anthropic",
@@ -92,7 +92,7 @@ describe("lazy provider module loading", () => {
 
 	it("loads only the Anthropic SDK when dispatching through streamSimple", () => {
 		const result = runProbe(`
-			const model = mod.getModel("anthropic", "claude-sonnet-4-20250514");
+			const model = mod.getModel("anthropic", "claude-sonnet-4-6");
 			const context = { messages: [{ role: "user", content: "hi" }] };
 			await mod.streamSimple(model, context).result();
 		`);

packages/ai/test/stream.test.ts

@@ -879,8 +879,8 @@ describe("Generate E2E Tests", () => {
 	// Tokens are resolved at module level (see oauthTokens above)
 	// =========================================================================
 
-	describe("Anthropic OAuth Provider (claude-sonnet-4-20250514)", () => {
+	describe("Anthropic OAuth Provider (claude-sonnet-4-6)", () => {
-		const model = getModel("anthropic", "claude-sonnet-4-20250514");
+		const model = getModel("anthropic", "claude-sonnet-4-6");
 
 		it.skipIf(!anthropicOAuthToken)("should complete basic text generation", { retry: 3 }, async () => {
 			await basicTextGeneration(model, { apiKey: anthropicOAuthToken });

packages/ai/test/total-tokens.test.ts

@@ -132,7 +132,7 @@ describe("totalTokens field", () => {
 			"claude-sonnet-4 - should return totalTokens equal to sum of components",
 			{ retry: 3, timeout: 60000 },
 			async () => {
-				const llm = getModel("anthropic", "claude-sonnet-4-20250514");
+				const llm = getModel("anthropic", "claude-sonnet-4-6");
 
 				console.log(`\nAnthropic OAuth / ${llm.id}:`);
 				const { first, second } = await testTotalTokensWithCache(llm, { apiKey: anthropicOAuthToken });