fix: stabilize flaky tests and sanitize directive-only chat tags

src/utils/directive-tags.test.ts

@@ -1,5 +1,8 @@
 import { describe, expect, test } from "vitest";
-import { stripInlineDirectiveTagsForDisplay } from "./directive-tags.js";
+import {
+  stripInlineDirectiveTagsForDisplay,
+  stripInlineDirectiveTagsFromMessageForDisplay,
+} from "./directive-tags.js";
 
 describe("stripInlineDirectiveTagsForDisplay", () => {
   test("removes reply and audio directives", () => {
@@ -23,3 +26,34 @@ describe("stripInlineDirectiveTagsForDisplay", () => {
     expect(result.text).toBe(input);
   });
 });
+
+describe("stripInlineDirectiveTagsFromMessageForDisplay", () => {
+  test("strips inline directives from text content blocks", () => {
+    const input = {
+      role: "assistant",
+      content: [{ type: "text", text: "hello [[reply_to_current]] world [[audio_as_voice]]" }],
+    };
+    const result = stripInlineDirectiveTagsFromMessageForDisplay(input);
+    expect(result).toBeDefined();
+    expect(result?.content).toEqual([{ type: "text", text: "hello  world " }]);
+  });
+
+  test("preserves empty-string text when directives are entire content", () => {
+    const input = {
+      role: "assistant",
+      content: [{ type: "text", text: "[[reply_to_current]]" }],
+    };
+    const result = stripInlineDirectiveTagsFromMessageForDisplay(input);
+    expect(result).toBeDefined();
+    expect(result?.content).toEqual([{ type: "text", text: "" }]);
+  });
+
+  test("returns original message when content is not an array", () => {
+    const input = {
+      role: "assistant",
+      content: "plain text",
+    };
+    const result = stripInlineDirectiveTagsFromMessageForDisplay(input);
+    expect(result).toEqual(input);
+  });
+});

src/utils/directive-tags.ts

@@ -29,6 +29,17 @@ type StripInlineDirectiveTagsResult = {
   changed: boolean;
 };
 
+type MessageTextPart = {
+  type: "text";
+  text: string;
+} & Record<string, unknown>;
+
+type MessagePart = Record<string, unknown> | null | undefined;
+
+export type DisplayMessageWithContent = {
+  content?: unknown;
+} & Record<string, unknown>;
+
 export function stripInlineDirectiveTagsForDisplay(text: string): StripInlineDirectiveTagsResult {
   if (!text) {
     return { text, changed: false };
@@ -41,6 +52,36 @@ export function stripInlineDirectiveTagsForDisplay(text: string): StripInlineDir
   };
 }
 
+function isMessageTextPart(part: MessagePart): part is MessageTextPart {
+  return Boolean(part) && part?.type === "text" && typeof part.text === "string";
+}
+
+/**
+ * Strips inline directive tags from message text blocks while preserving message shape.
+ * Empty post-strip text stays empty-string to preserve caller semantics.
+ */
+export function stripInlineDirectiveTagsFromMessageForDisplay(
+  message: DisplayMessageWithContent | undefined,
+): DisplayMessageWithContent | undefined {
+  if (!message) {
+    return message;
+  }
+  if (!Array.isArray(message.content)) {
+    return message;
+  }
+  const cleaned = message.content.map((part) => {
+    if (!part || typeof part !== "object") {
+      return part;
+    }
+    const record = part as MessagePart;
+    if (!isMessageTextPart(record)) {
+      return part;
+    }
+    return { ...record, text: stripInlineDirectiveTagsForDisplay(record.text).text };
+  });
+  return { ...message, content: cleaned };
+}
+
 export function parseInlineDirectives(
   text?: string,
   options: InlineDirectiveParseOptions = {},