fix: parse last_error as structured ChatError object (#36)

Author: mafredri

dist/index.js

@@ -441,9 +441,9 @@ describe("CoderAgentChatAction", () => {
 			expect(out.baseBranch).toBe("main");
 		});
 
-		test("converts null pull_request_title to undefined", () => {
-			// pull_request_title is .nullable().optional(); explicit null
-			// from the API maps to undefined so the output is unset.
+		test("converts empty pull_request_title to empty string", () => {
+			// pull_request_title is always a string from the API;
+			// an empty string passes through as-is.
 			const inputs = createMockInputs();
 			const action = new CoderAgentChatAction(
 				coderClient,
@@ -454,18 +454,18 @@ describe("CoderAgentChatAction", () => {
 			if (!diff) {
 				throw new Error("mockChatWithDiff must have diff_status set");
 			}
-			const chatWithNullTitle: typeof mockChatWithDiff = {
+			const chatWithEmptyTitle: typeof mockChatWithDiff = {
 				...mockChatWithDiff,
-				diff_status: { ...diff, pull_request_title: null },
+				diff_status: { ...diff, pull_request_title: "" },
 			};
 
 			const out = action.buildOutputs(
 				mockUser.username,
-				chatWithNullTitle,
+				chatWithEmptyTitle,
 				false,
 			);
 
-			expect(out.pullRequestTitle).toBeUndefined();
+			expect(out.pullRequestTitle).toBe("");
 		});
 
 		test("emits zero numerics when a PR exists", () => {
@@ -570,7 +570,7 @@ describe("CoderAgentChatAction", () => {
 			const chatWithError: typeof mockChat = {
 				...mockChat,
 				status: "error",
-				last_error: "spend cap reached",
+				last_error: { message: "spend cap reached", retryable: false },
 			};
 
 			const out = action.buildOutputs(mockUser.username, chatWithError, true);
@@ -919,7 +919,7 @@ describe("CoderAgentChatAction", () => {
 				.mockResolvedValueOnce({
 					...mockChat,
 					status: "error",
-					last_error: "Anthropic 429 rate limit",
+					last_error: { message: "Anthropic 429 rate limit", retryable: true },
 				});
 
 			const inputs = createMockInputs({
@@ -1413,7 +1413,7 @@ describe("CoderAgentChatAction", () => {
 				.mockResolvedValueOnce({
 					...mockChat,
 					status: "error",
-					last_error: "agent crashed",
+					last_error: { message: "agent crashed", retryable: false },
 				});
 
 			const existingChatId = "990e8400-e29b-41d4-a716-446655440000";

src/action.test.ts

@@ -218,7 +218,7 @@ export class CoderAgentChatAction {
 			changedFiles: hasPR ? diff?.changed_files : undefined,
 			headBranch: diff?.head_branch ?? undefined,
 			baseBranch: diff?.base_branch ?? undefined,
-			chatErrorMessage: chat.last_error ?? undefined,
+			chatErrorMessage: chat.last_error?.message ?? undefined,
 		};
 	}
 
@@ -337,7 +337,7 @@ export class CoderAgentChatAction {
 	 */
 	private throwOnChatError(chat: CoderChat): CoderChat {
 		if (chat.status === "error") {
-			const message = chat.last_error || "Chat ended in error state";
+			const message = chat.last_error?.message || "Chat ended in error state";
 			throw new ActionFailureError("api_error", message, chat);
 		}
 		return chat;

src/action.ts

@@ -199,6 +199,7 @@ export const ChatStatusSchema = z.enum([
 	"paused",
 	"completed",
 	"error",
+	"requires_action",
 ]);
 export type ChatStatus = z.infer<typeof ChatStatusSchema>;
 
@@ -207,7 +208,7 @@ export const ChatDiffStatusSchema = z.object({
 	chat_id: z.uuid(),
 	url: z.string().nullable().optional(),
 	pull_request_state: z.string().nullable().optional(),
-	pull_request_title: z.string().nullable().optional(),
+	pull_request_title: z.string(),
 	pull_request_draft: z.boolean().default(false),
 	changes_requested: z.boolean().default(false),
 	additions: z.number().default(0),
@@ -226,21 +227,32 @@ export const ChatDiffStatusSchema = z.object({
 });
 export type ChatDiffStatus = z.infer<typeof ChatDiffStatusSchema>;
 
+// Structured error returned by the Coder API when a chat fails.
+export const ChatErrorSchema = z.object({
+	message: z.string(),
+	detail: z.string().optional(),
+	kind: z.string().optional(),
+	provider: z.string().optional(),
+	retryable: z.boolean(),
+	status_code: z.number().optional(),
+});
+export type ChatError = z.infer<typeof ChatErrorSchema>;
+
 // Chat schema describes the full chat object returned by the API.
 export const CoderChatSchema = z.object({
 	id: ChatIdSchema,
 	owner_id: z.uuid(),
 	workspace_id: z.uuid().nullable().optional(),
 	parent_chat_id: z.uuid().nullable().optional(),
 	root_chat_id: z.uuid().nullable().optional(),
-	last_model_config_id: z.uuid().nullable().optional(),
+	last_model_config_id: z.uuid(),
 	title: z.string(),
 	status: ChatStatusSchema,
-	last_error: z.string().nullable().optional(),
+	last_error: ChatErrorSchema.nullable().optional(),
 	diff_status: ChatDiffStatusSchema.nullable().optional(),
 	created_at: z.string(),
 	updated_at: z.string(),
-	archived: z.boolean().nullable().optional(),
+	archived: z.boolean(),
 });
 export type CoderChat = z.infer<typeof CoderChatSchema>;
 

src/coder-client.ts

@@ -341,8 +341,8 @@ describe("CoderChatSchema", () => {
 		const result = CoderChatSchema.parse({
 			...mockChat,
 			status: "error",
-			last_error: "spend cap reached",
+			last_error: { message: "spend cap reached", retryable: false },
 		});
-		expect(result.last_error).toBe("spend cap reached");
+		expect(result.last_error?.message).toBe("spend cap reached");
 	});
 });