feat: add isContextOnly flag to extraction messages to prevent repeated extraction

- buildExtractionMessages marks messages with isContextOnly (seq < startIdx)
- formatExtractionTranscript inserts section dividers for mixed context/target
- extractor.js Layer 1 prompt splits context review vs extraction target with guidance
- Add tests/extraction-context-only-flag.mjs (7 test cases)

tests/extraction-context-only-flag.mjs

@@ -0,0 +1,140 @@
+import assert from "node:assert/strict";
+import {
+  buildExtractionMessages,
+} from "../maintenance/chat-history.js";
+import {
+  buildExtractionInputContext,
+  formatExtractionTranscript,
+} from "../maintenance/extraction-context.js";
+
+// ─── buildExtractionMessages: isContextOnly flag ───
+
+const chat = [
+  { is_user: false, is_system: true, mes: "greeting" },
+  { is_user: true, is_system: false, mes: "user-1" },
+  { is_user: false, is_system: false, mes: "assistant-1" },
+  { is_user: true, is_system: false, mes: "user-2" },
+  { is_user: false, is_system: false, mes: "assistant-2" },
+  { is_user: true, is_system: false, mes: "user-3" },
+  { is_user: false, is_system: false, mes: "assistant-3" },
+];
+
+{
+  const messages = buildExtractionMessages(chat, 4, 6, {
+    extractContextTurns: 2,
+  });
+  const contextOnly = messages.filter((m) => m.isContextOnly);
+  const target = messages.filter((m) => !m.isContextOnly);
+
+  assert.ok(
+    contextOnly.length > 0,
+    "should have context-only messages when extractContextTurns > 0",
+  );
+  assert.ok(
+    target.length > 0,
+    "should have extraction target messages",
+  );
+  assert.ok(
+    contextOnly.every((m) => m.seq < 4),
+    "context-only messages should have seq < startIdx",
+  );
+  assert.ok(
+    target.every((m) => m.seq >= 4),
+    "target messages should have seq >= startIdx",
+  );
+  console.log("  ✓ buildExtractionMessages: isContextOnly flag marks context vs target");
+}
+
+{
+  const messages = buildExtractionMessages(chat, 2, 6, {
+    extractContextTurns: 0,
+  });
+  const contextOnly = messages.filter((m) => m.isContextOnly);
+  assert.equal(
+    contextOnly.length,
+    0,
+    "no context-only messages when extractContextTurns=0 and startIdx=2",
+  );
+  console.log("  ✓ buildExtractionMessages: no context-only when contextTurns=0");
+}
+
+{
+  const messages = buildExtractionMessages(chat, 1, 6, {
+    extractContextTurns: 2,
+  });
+  const contextOnly = messages.filter((m) => m.isContextOnly);
+  assert.equal(
+    contextOnly.length,
+    0,
+    "no context-only when startIdx is already at the beginning",
+  );
+  console.log("  ✓ buildExtractionMessages: no context-only when startIdx at beginning");
+}
+
+// ─── formatExtractionTranscript: section dividers ───
+
+{
+  const mixed = [
+    { seq: 1, role: "user", content: "context user", speaker: "A", isContextOnly: true },
+    { seq: 2, role: "assistant", content: "context ai", speaker: "B", isContextOnly: true },
+    { seq: 3, role: "user", content: "target user", speaker: "A", isContextOnly: false },
+    { seq: 4, role: "assistant", content: "target ai", speaker: "B", isContextOnly: false },
+  ];
+  const transcript = formatExtractionTranscript(mixed);
+  assert.match(transcript, /已提取过/, "transcript should contain context review header");
+  assert.match(transcript, /本次需要提取/, "transcript should contain extraction target header");
+  assert.ok(
+    transcript.indexOf("已提取过") < transcript.indexOf("本次需要提取"),
+    "context header should appear before target header",
+  );
+  assert.match(transcript, /#1.*context user/, "context message should appear");
+  assert.match(transcript, /#3.*target user/, "target message should appear");
+  console.log("  ✓ formatExtractionTranscript: section dividers for mixed context/target");
+}
+
+{
+  const allTarget = [
+    { seq: 3, role: "user", content: "user msg", speaker: "A", isContextOnly: false },
+    { seq: 4, role: "assistant", content: "ai msg", speaker: "B", isContextOnly: false },
+  ];
+  const transcript = formatExtractionTranscript(allTarget);
+  assert.doesNotMatch(transcript, /已提取过/, "no context header when all are target");
+  assert.doesNotMatch(transcript, /本次需要提取/, "no target header when all are target");
+  console.log("  ✓ formatExtractionTranscript: no dividers when all messages are targets");
+}
+
+{
+  const allContext = [
+    { seq: 1, role: "user", content: "user msg", speaker: "A", isContextOnly: true },
+    { seq: 2, role: "assistant", content: "ai msg", speaker: "B", isContextOnly: true },
+  ];
+  const transcript = formatExtractionTranscript(allContext);
+  assert.doesNotMatch(transcript, /已提取过/, "no dividers when all are context-only");
+  assert.doesNotMatch(transcript, /本次需要提取/, "no dividers when all are context-only");
+  console.log("  ✓ formatExtractionTranscript: no dividers when all messages are context-only");
+}
+
+// ─── buildExtractionInputContext: isContextOnly propagation ───
+
+{
+  const inputMessages = [
+    { seq: 1, role: "user", content: "old question", name: "A", speaker: "A", isContextOnly: true },
+    { seq: 2, role: "assistant", content: "old answer", name: "B", speaker: "B", isContextOnly: true },
+    { seq: 3, role: "user", content: "new question", name: "A", speaker: "A", isContextOnly: false },
+    { seq: 4, role: "assistant", content: "new answer", name: "B", speaker: "B", isContextOnly: false },
+  ];
+  const result = buildExtractionInputContext(inputMessages, {
+    settings: {},
+    userName: "A",
+    charName: "B",
+  });
+  const contextFiltered = result.filteredMessages.filter((m) => m.isContextOnly);
+  const targetFiltered = result.filteredMessages.filter((m) => !m.isContextOnly);
+  assert.equal(contextFiltered.length, 2, "context messages propagated through filtering");
+  assert.equal(targetFiltered.length, 2, "target messages propagated through filtering");
+  assert.match(result.filteredTranscript, /已提取过/, "transcript includes context header");
+  assert.match(result.filteredTranscript, /本次需要提取/, "transcript includes target header");
+  console.log("  ✓ buildExtractionInputContext: isContextOnly propagated to filteredMessages and transcript");
+}
+
+console.log("extraction-context-only-flag tests passed");