fix(council-archive): handle literal tag mentions inside response content

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/council-archive/council-response-extractor.ts

@@ -10,22 +10,104 @@ export interface CouncilResponseExtraction {
 }
 
 export function extractCouncilResponse(fullText: string): CouncilResponseExtraction {
-  const lastOpenIdx = fullText.lastIndexOf(OPENING_TAG)
-  if (lastOpenIdx === -1) {
-    return { has_response: false, response_complete: false, result: null }
-  }
+  const lastCloseIdx = findLastStructuralClose(fullText)
 
-  const contentStart = lastOpenIdx + OPENING_TAG.length
-  const closingAfterLastOpen = fullText.indexOf(CLOSING_TAG, contentStart)
-
-  if (closingAfterLastOpen === -1) {
-    const partial = fullText.slice(contentStart).trim()
+  if (lastCloseIdx === -1) {
+    const lastOpenIdx = findLastStructuralOpen(fullText)
+    if (lastOpenIdx === -1) {
+      return { has_response: false, response_complete: false, result: null }
+    }
+    const partial = fullText.slice(lastOpenIdx + OPENING_TAG.length).trim()
     return { has_response: true, response_complete: false, result: partial || null }
   }
 
-  const content = fullText.slice(contentStart, closingAfterLastOpen).trim()
+  const openAfterLastClose = findFirstStructuralOpenAfter(fullText, lastCloseIdx + CLOSING_TAG.length)
+  if (openAfterLastClose !== -1) {
+    const partial = fullText.slice(openAfterLastClose + OPENING_TAG.length).trim()
+    return { has_response: true, response_complete: false, result: partial || null }
+  }
+
+  const matchingOpenIdx = findLastStructuralOpenBefore(fullText, lastCloseIdx)
+  if (matchingOpenIdx === -1) {
+    return { has_response: false, response_complete: false, result: null }
+  }
+
+  const content = fullText.slice(matchingOpenIdx + OPENING_TAG.length, lastCloseIdx).trim()
   if (content.length < MIN_RESPONSE_LENGTH) {
     return { has_response: false, response_complete: true, result: content }
   }
   return { has_response: true, response_complete: true, result: content }
 }
+
+function isStructuralOpen(text: string, idx: number): boolean {
+  return idx === 0 || text[idx - 1] === "\n"
+}
+
+function isStructuralClose(text: string, idx: number): boolean {
+  const afterIdx = idx + CLOSING_TAG.length
+  return afterIdx === text.length || text[afterIdx] === "\n"
+}
+
+function findLastStructuralClose(text: string): number {
+  let searchFrom = text.length
+  while (searchFrom >= 0) {
+    const idx = text.lastIndexOf(CLOSING_TAG, searchFrom - 1)
+    if (idx === -1) return -1
+    if (isStructuralClose(text, idx)) return idx
+    searchFrom = idx
+  }
+  return -1
+}
+
+function findLastStructuralOpen(text: string): number {
+  let searchFrom = text.length
+  while (searchFrom >= 0) {
+    const idx = text.lastIndexOf(OPENING_TAG, searchFrom - 1)
+    if (idx === -1) return -1
+    if (isStructuralOpen(text, idx)) return idx
+    searchFrom = idx
+  }
+  return -1
+}
+
+function findFirstStructuralOpenAfter(text: string, fromIdx: number): number {
+  let searchFrom = fromIdx
+  while (searchFrom < text.length) {
+    const idx = text.indexOf(OPENING_TAG, searchFrom)
+    if (idx === -1) return -1
+    if (isStructuralOpen(text, idx)) return idx
+    searchFrom = idx + OPENING_TAG.length
+  }
+  return -1
+}
+
+function findLastStructuralOpenBefore(text: string, beforeIdx: number): number {
+  let searchFrom = beforeIdx
+  let nestedCloseCount = 0
+
+  while (searchFrom > 0) {
+    const openIdx = text.lastIndexOf(OPENING_TAG, searchFrom - 1)
+    const closeIdx = text.lastIndexOf(CLOSING_TAG, searchFrom - 1)
+
+    if (openIdx === -1 && closeIdx === -1) return -1
+
+    if (closeIdx > openIdx) {
+      if (isStructuralClose(text, closeIdx)) {
+        nestedCloseCount += 1
+      }
+      searchFrom = closeIdx
+      continue
+    }
+
+    if (!isStructuralOpen(text, openIdx)) {
+      searchFrom = openIdx
+      continue
+    }
+
+    if (nestedCloseCount === 0) return openIdx
+    nestedCloseCount -= 1
+    searchFrom = openIdx
+  }
+
+  return -1
+}