chuks-qua · Oct 21, 2026 · Oct 21, 2026 · Oct 21, 2026 · Oct 21, 2026 · Oct 21, 2026
@@ -377,7 +377,11 @@ describe("provider switch on send", () => {
     const request = lastRequest(claude);
     expect(request.codexFastMode).toBeUndefined();
     expect(request.reasoningLevel).toBeUndefined();
-    const audit = await container.resolve(HandoffStorage).readLatestHandoffAudit(threadId);
+    const audit = await vi.waitFor(async () => {
+      const written = await container.resolve(HandoffStorage).readLatestHandoffAudit(threadId);
+      if (written === null) throw new Error("The switch audit is not written yet");
+      return written;
+    });
     expect(audit).toContain("schemaVersion: 2");
     expect(audit).toContain("kind: switch");
     expect(audit).toContain('fromProvider: "codex"');
@@ -446,7 +450,10 @@ describe("provider switch on send", () => {
     expect(retry.message.match(/\[mcode-handoff:begin /g)).toHaveLength(1);
     expect(retry.message.match(/ancient question/g)).toHaveLength(1);
     expect(retry.message.endsWith("back on claude")).toBe(true);
-    expect(await container.resolve(HandoffStorage).readLatestHandoffAudit(threadId)).toContain("kind: switch");
+    // The switch writes its audit after it saves the provider, so the audit can trail the turn's settlement.
+    await vi.waitFor(async () => {
+      expect(await container.resolve(HandoffStorage).readLatestHandoffAudit(threadId)).toContain("kind: switch");
+    });
   });
 
   function notices(): string[] {

@@ -69,6 +69,14 @@ describe("HandoffStorage", () => {
     expect((await storage.readLatest("child"))?.meta).toMatchObject({ fromProvider: null, toProvider: "custom: provider\nname" });
   });
 
+  it("skips an audit whose write is still in progress", async () => {
+    await storage.writeHandoffAudit("child", audit);
+    const inProgress = NodePath.join(dir, "threads", "child", "handoffs", "ZZZ-in-progress");
+    await NodeFSPromises.mkdir(inProgress, { recursive: true });
+    await NodeFSPromises.writeFile(NodePath.join(inProgress, "handoff.md.partial"), "---\nschemaVersion: 2\n");
+    expect((await storage.readLatest("child"))?.meta.kind).toBe("switch");
+  });
+
   it("returns null for an absent thread and removes audits on thread deletion", async () => {
     expect(await storage.readLatest("absent")).toBeNull();
     await storage.writeHandoffAudit("child", audit);

@@ -42,6 +42,8 @@ export class HandoffStorage {
       const dir = NodePath.join(handoffsRoot, entry);
       // Pre-v2 artifacts have separate JSON metadata and must not enter the v2 wire contract.
       if (NodeFS.existsSync(NodePath.join(dir, "handoff.json"))) continue;
+      // An audit still being written has its directory but not yet its renamed handoff.md.
+      if (!NodeFS.existsSync(NodePath.join(dir, "handoff.md"))) continue;
       const markdown = await NodeFSPromises.readFile(NodePath.join(dir, "handoff.md"), "utf8");
       const meta = readAuditMetadata(markdown);
       if (meta) return { markdown, meta };
@@ -64,7 +66,10 @@ export class HandoffStorage {
       `budgetBytes: ${audit.budgetBytes}`,
       `droppedOptions: ${JSON.stringify(audit.droppedOptions)}`,
     ].join("\n");
-    await NodeFSPromises.writeFile(NodePath.join(handoffDir, "handoff.md"), `---\n${frontmatter}\n---\n\n${audit.history}\n`, "utf8");
+    // Readers must never see a half-written audit, so handoff.md appears only once it is complete.
+    const partialPath = NodePath.join(handoffDir, "handoff.md.partial");
+    await NodeFSPromises.writeFile(partialPath, `---\n${frontmatter}\n---\n\n${audit.history}\n`, "utf8");
+    await NodeFSPromises.rename(partialPath, NodePath.join(handoffDir, "handoff.md"));
     return ulid;
   }
 

@@ -31,6 +31,24 @@ describe("resolveUserMessagePreview", () => {
     );
   });
 
+  it.each([
+    ["call thread_target_list then delegate_task", "call thread_target_list then delegate_task"],
+    ["see `src/__tests__/a_b.ts`", "see src/__tests__/a_b.ts"],
+    ["open https://example.com/wiki/Foo_(bar)", "open https://example.com/wiki/Foo_(bar)"],
+    ["fix issue #2269 when a > b and [x] is set", "fix issue #2269 when a > b and [x] is set"],
+    ["2 * 3 * 4 = 24", "2 * 3 * 4 = 24"],
+  ])("keeps literal characters in %j", (content, expected) => {
+    expect(resolveUserMessagePreview(userMessage({ content }))).toBe(expected);
+  });
+
+  it.each([
+    ["## Plan\n> quoted _note_", "Plan quoted note"],
+    ["read [the docs](https://example.com/a_(b)) first", "read the docs first"],
+    ["__bold__ and ~~gone~~", "bold and gone"],
+  ])("drops markdown syntax in %j", (content, expected) => {
+    expect(resolveUserMessagePreview(userMessage({ content }))).toBe(expected);
+  });
+
   it("returns goal conditions for /goal set commands", () => {
     expect(resolveUserMessagePreview(userMessage({ content: "/goal ship sticky messages" }))).toBe(
       "ship sticky messages",

@@ -1,5 +1,6 @@
 import { PLAN_ANSWER_MESSAGE_PREFIX } from "@mcode/contracts";
 import { stripInjectedFiles } from "@/lib/file-tags";
+import { stripInlineMarkdown } from "@/lib/inline-markdown";
 import type { Message } from "@/transport";
 
 /**
@@ -16,16 +17,16 @@ function parseUserGoalCommand(content: string): { condition: string } | null {
   return { condition: arg };
 }
 
+const BLOCK_MARKER = /^[ \t]{0,3}(?:#{1,6}[ \t]+|(?:>[ \t]?)+)/gm;
+
 /** Collapses markdown noise so sticky previews stay readable in one or two lines. */
 function toPlainPreview(text: string): string {
   const codeBlocks = [...text.matchAll(/```[\w-]*\n?([\s\S]*?)```/g)]
     .map((match) => match[1]?.trim() ?? "")
     .filter(Boolean);
 
-  const plain = text
-    .replace(/```[\s\S]*?```/g, " ")
-    .replace(/`([^`]+)`/g, "$1")
-    .replace(/[#*_>~[\]()]/g, "")
+  const plain = stripInlineMarkdown(text.replace(/```[\s\S]*?```/g, " "))
+    .replace(BLOCK_MARKER, "")
     .replace(/\s+/g, " ")
     .trim();
 

@@ -1,3 +1,5 @@
+import { stripInlineMarkdown } from "@/lib/inline-markdown";
+
 /** Release notes reduced to plain text the update card can render safely. */
 export interface ParsedReleaseNotes {
   /** Up to {@link MAX_RELEASE_NOTE_ITEMS} list items, as plain text. */
@@ -16,8 +18,6 @@ const MARKDOWN_HEADING = /^\s{0,3}#{1,6}\s/;
 const EXECUTABLE_BLOCK = /<(script|style)\b[^>]*>[\s\S]*?(?:<\/\1\s*>|$)/gi;
 const HTML_HEADING_BLOCK = /<h[1-6]\b[^>]*>[\s\S]*?<\/h[1-6]\s*>/gi;
 const BLOCK_BOUNDARY = /<\/?(?:p|div|ul|ol|li|br|hr|h[1-6]|blockquote|pre|table|tr)\b[^>]*>/gi;
-// Link targets may hold one level of parentheses, as in javascript:alert(1).
-const MARKDOWN_LINK = /!?\[([^\]]*)\]\((?:[^()]|\([^()]*\))*\)/g;
 const ANY_TAG = /<\/?[a-z!][^>]*>/gi;
 
 const NAMED_ENTITIES: Readonly<Record<string, string>> = {
@@ -39,20 +39,10 @@ function decodeEntities(text: string): string {
   });
 }
 
-function stripMarkdown(text: string): string {
-  return text
-    .replace(MARKDOWN_LINK, "$1")
-    .replace(/\[([^\]]*)\]\[[^\]]*\]/g, "$1")
-    .replace(/`+([^`]*)`+/g, "$1")
-    .replace(/(\*\*|__)(.+?)\1/g, "$2")
-    .replace(/(^|[^\w*])[*_]([^*_]+)[*_](?=[^\w*]|$)/g, "$1$2")
-    .replace(/~~(.+?)~~/g, "$1");
-}
-
 /** Reduces one fragment of HTML or markdown to a single line of plain text. */
 function toPlainText(fragment: string): string {
   const withoutTags = fragment.replace(EXECUTABLE_BLOCK, " ").replace(BLOCK_BOUNDARY, " ").replace(ANY_TAG, "");
-  return decodeEntities(stripMarkdown(withoutTags)).replace(/\s+/g, " ").trim();
+  return decodeEntities(stripInlineMarkdown(withoutTags)).replace(/\s+/g, " ").trim();
 }
 
 function htmlListItems(notes: string): string[] {

@@ -0,0 +1,36 @@
+const CODE_SPAN = /(`+)([\s\S]*?)\1/g;
+const INLINE_LINK_ONE_PAREN_LEVEL = /!?\[([^\]]*)\]\((?:[^()]|\([^()]*\))*\)/g;
+const REFERENCE_LINK = /\[([^\]]*)\]\[[^\]]*\]/g;
+// Delimiters only count when they hug non-space text, so `2 * 3 * 4` keeps its stars.
+const STRONG_STARS = /\*\*(?=\S)([\s\S]*?\S)\*\*/g;
+const EMPHASIS_STAR = /\*(?=[^\s*])([^*]*?[^\s*])\*/g;
+// Underscores never open or close inside a word, so `snake_case` stays intact.
+const STRONG_UNDERSCORES = /(?<!\w)__(?=\S)([\s\S]*?\S)__(?!\w)/g;
+const EMPHASIS_UNDERSCORE = /(?<!\w)_(?=[^\s_])([^_]*?[^\s_])_(?!\w)/g;
+const STRIKETHROUGH = /~~(?=\S)([\s\S]*?\S)~~/g;
+
+function stripDelimiters(prose: string): string {
+  return prose
+    .replace(INLINE_LINK_ONE_PAREN_LEVEL, "$1")
+    .replace(REFERENCE_LINK, "$1")
+    .replace(STRONG_STARS, "$1")
+    .replace(STRONG_UNDERSCORES, "$1")
+    .replace(EMPHASIS_STAR, "$1")
+    .replace(EMPHASIS_UNDERSCORE, "$1")
+    .replace(STRIKETHROUGH, "$1");
+}
+
+/**
+ * Removes inline Markdown syntax (links, emphasis, strikethrough, code-span
+ * backticks) and keeps every other character. Code span contents are kept
+ * verbatim because their underscores and brackets are literal.
+ */
+export function stripInlineMarkdown(text: string): string {
+  let plain = "";
+  let proseStart = 0;
+  for (const match of text.matchAll(CODE_SPAN)) {
+    plain += stripDelimiters(text.slice(proseStart, match.index)) + (match[2] ?? "");
+    proseStart = match.index + match[0].length;
+  }
+  return plain + stripDelimiters(text.slice(proseStart));
+}