Keep multi-turn conversations linked to their card

The first pass read the name from the last user turn and the token from
the last assistant turn. Both are wrong once a conversation continues.

Only sucker's *first* reply carries a conversation token — later ones say
"Character updated" or "unchanged" with no token in them — so reading the
last assistant turn lost the link three turns in and would have created a
duplicate card on every message. tokenCandidates() now searches the whole
conversation, still preferring whatever the user just typed, since pasting
a token is deliberate.

The name is the first user turn after the greeting, not the last one. That
is what the old code read at messages[3], and unlike the last turn it stays
put as messages are appended.

Tests cover a three-turn conversation for both.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NX2SsmUqQftWTZAY4BDuFa

src/app/api/proxy/route.ts

@@ -1,6 +1,10 @@
 import { NextResponse } from "next/server";
 import type { NextRequest } from "next/server";
-import { selectMessageSlots, type Message } from "@/lib/messages";
+import {
+  selectMessageSlots,
+  tokenCandidates,
+  type Message,
+} from "@/lib/messages";
 
 interface CardVersion {
   version: number;
@@ -115,7 +119,7 @@ function removePersonaTags(content: string): string {
 }
 
 function extractCardData(messages: Message[]): ExtractedCard {
-  const { system, greeting, lastUser } = selectMessageSlots(messages);
+  const { system, greeting, nameSlot } = selectMessageSlots(messages);
 
   if (!system?.content) {
     throw new Error("No system message: this request carries no character card.");
@@ -126,7 +130,7 @@ function extractCardData(messages: Message[]): ExtractedCard {
 
   const first_mes = greeting.content.replace(/{user}/g, "{{user}}");
 
-  const nameContent = lastUser?.content ?? "";
+  const nameContent = nameSlot?.content ?? "";
   // If the name slot is actually a token, ignore it for naming purposes
   const tokenInNameSlot = parseConversationToken(nameContent);
   const lastColonIndex = nameContent.lastIndexOf(": ");
@@ -346,16 +350,14 @@ export async function POST(request: NextRequest) {
       );
     }
 
-    // The token is either in what the user just typed, or in sucker's own
+    // The token may be in what the user just typed, or in sucker's own first
-    // previous reply. Both are found by role, so a missing "." turn or a
+    // reply from earlier in the conversation. Search every message rather than
-    // longer conversation cannot shift them out from under us.
+    // a fixed pair of slots: only the first reply carries a token, so a long
-    const tokenSlots = selectMessageSlots(body.messages);
+    // chat would otherwise lose the link and duplicate the card.
-    const tokenCandidateUser: string | undefined = tokenSlots.lastUser?.content;
-    const tokenCandidateAssistant: string | undefined =
-      tokenSlots.lastAssistant?.content;
     const providedConversationId =
-      parseConversationToken(tokenCandidateUser || undefined) ||
+      tokenCandidates(body.messages)
-      parseConversationToken(tokenCandidateAssistant || undefined);
+        .map((c) => parseConversationToken(c))
+        .find((id): id is string => Boolean(id)) ?? null;
 
     let existingCard: StoredCard | null = null;
     let linkedByToken = false;

src/lib/messages.ts

@@ -8,13 +8,14 @@
  * TypeError that reached the user as the "you dingus" message, blaming them
  * for something they had no control over.
  *
- * So nothing here depends on a position. What is actually stable:
+ * So nothing here depends on a position. What is actually stable, in both
+ * shapes and however long the conversation runs:
  *
  *   - the card is the system turn;
  *   - the greeting is the FIRST assistant turn;
- *   - whatever the user just typed is the LAST user turn;
+ *   - the name is the first user turn AFTER the greeting — the one the user
- *   - sucker's own previous reply, which carries the conversation token, is
+ *     typed to start, which stays put as more turns are appended;
- *     the LAST assistant turn.
+ *   - what the user typed most recently is the LAST user turn.
  *
  * If JanitorAI changes the shape again, this is the only file that should
  * need to know.
@@ -30,23 +31,47 @@ export interface MessageSlots {
   system: Message | undefined;
   /** The character's opening message. */
   greeting: Message | undefined;
-  /** What the user typed most recently — the name, or a conversation token. */
+  /** The name — or conversation token — the user typed to start the chat. */
+  nameSlot: Message | undefined;
+  /** Whatever the user typed most recently. */
   lastUser: Message | undefined;
-  /** Sucker's own most recent reply, when there is one. */
-  lastAssistant: Message | undefined;
 }
 
-export function selectMessageSlots(messages: Message[] | undefined): MessageSlots {
+export function selectMessageSlots(
+  messages: Message[] | undefined
+): MessageSlots {
   const list = Array.isArray(messages) ? messages : [];
-  const assistants = list.filter((m) => m?.role === "assistant");
+  const greetingIndex = list.findIndex((m) => m?.role === "assistant");
   const users = list.filter((m) => m?.role === "user");
 
   return {
     // Falling back to the first message keeps working if a client ever omits
     // the role on the card, which is where it has always been.
     system: list.find((m) => m?.role === "system") ?? list[0],
-    greeting: assistants[0],
+    greeting: greetingIndex === -1 ? undefined : list[greetingIndex],
+    nameSlot:
+      greetingIndex === -1
+        ? undefined
+        : list.slice(greetingIndex + 1).find((m) => m?.role === "user"),
     lastUser: users[users.length - 1],
-    lastAssistant: assistants[assistants.length - 1],
   };
 }
+
+/**
+ * Message contents to search for a conversation token, most promising first.
+ *
+ * Only sucker's *first* reply carries a token — every later reply says
+ * "Character updated" or "unchanged" with no token in it. So a long
+ * conversation has to be searched all the way back rather than at its tail,
+ * or the link to the existing card is lost and a duplicate gets created.
+ * What the user just typed still wins, since pasting a token is deliberate.
+ */
+export function tokenCandidates(messages: Message[] | undefined): string[] {
+  const list = Array.isArray(messages) ? messages : [];
+  const users = list.filter((m) => m?.role === "user");
+  const mostRecentUser = users[users.length - 1];
+
+  return [mostRecentUser, ...list.filter((m) => m !== mostRecentUser)]
+    .map((m) => m?.content)
+    .filter((c): c is string => typeof c === "string" && c.length > 0);
+}

tests/messages.test.ts

@@ -1,18 +1,19 @@
 /**
- * Both request shapes JanitorAI sends, and a continued conversation.
+ * Both request shapes JanitorAI sends, and conversations that keep going.
  * Run with `npm test` — no test framework, just node's built-in runner.
  */
 import { test } from "node:test";
 import assert from "node:assert/strict";
-import { selectMessageSlots } from "../src/lib/messages.ts";
+import { selectMessageSlots, tokenCandidates } from "../src/lib/messages.ts";
 
 const CARD =
   "<.>\n<Gaius's Persona>a tired innkeeper</Gaius's Persona><UserPersona>.</UserPersona>";
 const GREETING = "The clink of bottles is the only greeting you get.";
 const NAME = "{{user}}: Gaius";
+const TOKEN = "[sucker:conv=abc123]";
 
 /** What most clients send: a throwaway "." user turn before the greeting. */
-const withProbe = [
+const withProbe: { role: string; content: string }[] = [
   { role: "system", content: CARD },
   { role: "user", content: "." },
   { role: "assistant", content: GREETING },
@@ -20,12 +21,21 @@ const withProbe = [
 ];
 
 /** What some clients send: no "." turn, so every index shifts by one. */
-const withoutProbe = [
+const withoutProbe: { role: string; content: string }[] = [
   { role: "system", content: CARD },
   { role: "assistant", content: GREETING },
   { role: "user", content: NAME },
 ];
 
+/** Three turns in. Only sucker's FIRST reply carries the token. */
+const continued = [
+  ...withProbe,
+  { role: "assistant", content: `New character "Gaius" created (v1). ${TOKEN}` },
+  { role: "user", content: "{{user}}: keep going" },
+  { role: "assistant", content: "Character data unchanged (v1, message 2)." },
+  { role: "user", content: "{{user}}: and again" },
+];
+
 test("both shapes resolve to the same slots", () => {
   for (const [label, messages] of [
     ["with probe", withProbe],
@@ -34,21 +44,31 @@ test("both shapes resolve to the same slots", () => {
     const slots = selectMessageSlots(messages);
     assert.equal(slots.system?.content, CARD, `${label}: card`);
     assert.equal(slots.greeting?.content, GREETING, `${label}: greeting`);
-    assert.equal(slots.lastUser?.content, NAME, `${label}: name slot`);
+    assert.equal(slots.nameSlot?.content, NAME, `${label}: name`);
   }
 });
 
-test("the greeting stays the first assistant turn as a chat continues", () => {
+test("the greeting and the name stay put as a conversation grows", () => {
-  const continued = [
-    ...withProbe,
-    { role: "assistant", content: "Character updated (v2)." },
-    { role: "user", content: "{{user}}: [sucker:conv=abc123]" },
-  ];
   const slots = selectMessageSlots(continued);
   assert.equal(slots.greeting?.content, GREETING);
-  // Sucker's own reply, where a conversation token would be found.
+  // Not "keep going" or "and again": the name is what started the chat.
-  assert.equal(slots.lastAssistant?.content, "Character updated (v2).");
+  assert.equal(slots.nameSlot?.content, NAME);
-  assert.equal(slots.lastUser?.content, "{{user}}: [sucker:conv=abc123]");
+  assert.equal(slots.lastUser?.content, "{{user}}: and again");
+});
+
+test("the token is still found once later replies stop carrying it", () => {
+  const found = tokenCandidates(continued).find((c) => c.includes("sucker:conv="));
+  assert.ok(found, "a token must still be discoverable three turns in");
+  assert.match(found!, /\[sucker:conv=abc123\]/);
+});
+
+test("a token the user just pasted outranks an older one", () => {
+  const candidates = tokenCandidates([
+    ...withProbe,
+    { role: "assistant", content: `created (v1). ${TOKEN}` },
+    { role: "user", content: "{{user}}: [sucker:conv=zzz999]" },
+  ]);
+  assert.match(candidates[0], /zzz999/);
 });
 
 test("a card with no role on the system turn still resolves", () => {
@@ -63,6 +83,8 @@ test("a card with no role on the system turn still resolves", () => {
 test("nothing throws on empty or malformed input", () => {
   for (const input of [[], undefined, [{}, { role: "user" }]]) {
     assert.doesNotThrow(() => selectMessageSlots(input as never));
+    assert.doesNotThrow(() => tokenCandidates(input as never));
   }
   assert.equal(selectMessageSlots([]).greeting, undefined);
+  assert.deepEqual(tokenCandidates(undefined), []);
 });