fix(context): hide normalized resume manifests

src/domain/chat/context-manifest.ts

@@ -48,6 +48,8 @@ export interface UserMessageContextProjection {
   manifest: TurnContextManifest | null;
 }
 
+type UserMessageContentItem = { type: "text"; text: string } | { type: string };
+
 export function turnContextManifestText(manifest: TurnContextManifest): string {
   return `${TURN_CONTEXT_MANIFEST_PREFIX}${TURN_CONTEXT_MANIFEST_NOTICE}${JSON.stringify(manifest)}`;
 }
@@ -110,19 +112,21 @@ function turnContextManifestFromText(text: string): TurnContextManifest | null {
 }
 
 export function userMessageContextProjection(
-  content: readonly ({ type: "text"; text: string } | { type: string })[],
+  content: readonly UserMessageContentItem[],
   clientId: string | null,
 ): UserMessageContextProjection {
   let manifest: TurnContextManifest | null = null;
   const visibleText: string[] = [];
+  const lastTextIndex = lastTextItemIndex(content);
   for (const [index, item] of content.entries()) {
     if (item.type !== "text" || !("text" in item) || typeof item.text !== "string") continue;
-    const parsed =
-      index > 0 && index === content.length - 1 && item.text.startsWith(`\n${TURN_CONTEXT_MANIFEST_PREFIX}`)
-        ? turnContextManifestFromText(item.text)
-        : null;
+    const manifestPrefix = `\n${TURN_CONTEXT_MANIFEST_PREFIX}`;
+    const manifestStart = index === lastTextIndex ? item.text.lastIndexOf(manifestPrefix) : -1;
+    const isStandaloneManifest = manifestStart === 0 && index > 0 && index === content.length - 1;
+    const parsed = manifestStart > 0 || isStandaloneManifest ? turnContextManifestFromText(item.text.slice(manifestStart)) : null;
     if (parsed && manifestMatchesClientId(parsed, clientId)) {
       manifest = parsed;
+      if (manifestStart > 0) visibleText.push(item.text.slice(0, manifestStart));
       continue;
     }
     visibleText.push(item.text);
@@ -130,6 +134,13 @@ export function userMessageContextProjection(
   return { text: visibleText.join("\n"), manifest };
 }
 
+function lastTextItemIndex(content: readonly UserMessageContentItem[]): number {
+  for (let index = content.length - 1; index >= 0; index -= 1) {
+    if (content[index]?.type === "text") return index;
+  }
+  return -1;
+}
+
 export function turnContextSubmissionId(value: string): string {
   const safe = value.replace(/[^A-Za-z0-9_.-]/g, "_").slice(0, 120);
   return safe || "context";

tests/domain/chat/context-manifest.test.ts

@@ -205,6 +205,24 @@ describe("turn context manifest trust matching", () => {
     });
   });
 
+  it("hides a trusted manifest appended to visible text by resume normalization", () => {
+    expect(
+      userMessageContextProjection([{ type: "text", text: `visible request\n${turnContextManifestText(validManifest())}` }], SUBMISSION_ID),
+    ).toEqual({
+      text: "visible request",
+      manifest: validManifest(),
+    });
+  });
+
+  it("keeps an appended manifest-like suffix visible when its client ID is not trusted", () => {
+    const text = `visible request\n${turnContextManifestText(validManifest())}`;
+
+    expect(userMessageContextProjection([{ type: "text", text }], "foreign-client")).toEqual({
+      text,
+      manifest: null,
+    });
+  });
+
   it.each([
     ["submission mismatch", { submissionId: "local-user-2-seed-2-2" }],
     ["context mismatch", { contexts: [{ ...validManifest().contexts[0], id: `${SUBMISSION_ID}.99x` }] }],

tests/features/chat/app-server/mappers/thread-stream.test.ts

@@ -118,6 +118,33 @@ describe("turn item conversion preserves app-server semantics", () => {
     });
   });
 
+  it("restores v2 metadata when resume merges text before a non-text input", () => {
+    const clientId = "local-user-1-seed-1-1";
+    const prepared = appServerTurnInputFromCodexInput(
+      [
+        { type: "text", text: "Read [[Alpha]]." },
+        { type: "fileReference", name: "Alpha", path: "thoughts/Alpha.md" },
+        { type: "localImage", path: "/tmp/chart.png" },
+      ],
+      clientId,
+    );
+    const normalizedText = prepared.input.flatMap((item) => (item.type === "text" ? [item.text] : [])).join("");
+    const nonTextInput = prepared.input.filter((item) => item.type !== "text");
+
+    expect(
+      threadStreamItemFromTurnItem({
+        type: "userMessage",
+        id: "u1",
+        clientId,
+        content: [{ type: "text", text: normalizedText, text_elements: [] }, ...nonTextInput],
+      }),
+    ).toMatchObject({
+      text: "Read [[Alpha]].\n[local image] /tmp/chart.png",
+      copyText: "Read [[Alpha]].\n[local image] /tmp/chart.png",
+      referencedFiles: [{ name: "Alpha", path: "thoughts/Alpha.md" }],
+    });
+  });
+
   it("accepts a persisted attachment descriptor after an unpersisted reference context", () => {
     const clientId = "local-user-1-seed-1-1";
     const prepared = appServerTurnInputFromCodexInput(