fix(hooks): improve thinking block order recovery with error-based index targeting

- Add findMessageByIndexNeedingThinking for precise message targeting
- Detect "expected X found Y" error pattern for thinking block order
- Remove isLastMessage skip - recovery now handles final assistant messages
- Simplify orphan detection: any non-thinking first part is orphan

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/session-recovery/index.ts

@@ -3,6 +3,7 @@ import type { createOpencodeClient } from "@opencode-ai/sdk"
 import {
   findEmptyMessages,
   findEmptyMessageByIndex,
+  findMessageByIndexNeedingThinking,
   findMessagesWithOrphanThinking,
   findMessagesWithThinkingBlocks,
   injectTextPart,
@@ -70,7 +71,10 @@ function detectErrorType(error: unknown): RecoveryErrorType {
 
   if (
     message.includes("thinking") &&
-    (message.includes("first block") || message.includes("must start with") || message.includes("preceeding"))
+    (message.includes("first block") ||
+      message.includes("must start with") ||
+      message.includes("preceeding") ||
+      (message.includes("expected") && message.includes("found")))
   ) {
     return "thinking_block_order"
   }
@@ -125,8 +129,17 @@ async function recoverThinkingBlockOrder(
   _client: Client,
   sessionID: string,
   _failedAssistantMsg: MessageData,
-  _directory: string
+  _directory: string,
+  error: unknown
 ): Promise<boolean> {
+  const targetIndex = extractMessageIndex(error)
+  if (targetIndex !== null) {
+    const targetMessageID = findMessageByIndexNeedingThinking(sessionID, targetIndex)
+    if (targetMessageID) {
+      return prependThinkingPart(sessionID, targetMessageID)
+    }
+  }
+
   const orphanMessages = findMessagesWithOrphanThinking(sessionID)
 
   if (orphanMessages.length === 0) {
@@ -275,7 +288,7 @@ export function createSessionRecoveryHook(ctx: PluginInput) {
       if (errorType === "tool_result_missing") {
         success = await recoverToolResultMissing(ctx.client, sessionID, failedMsg)
       } else if (errorType === "thinking_block_order") {
-        success = await recoverThinkingBlockOrder(ctx.client, sessionID, failedMsg, ctx.directory)
+        success = await recoverThinkingBlockOrder(ctx.client, sessionID, failedMsg, ctx.directory, info.error)
       } else if (errorType === "thinking_disabled_violation") {
         success = await recoverThinkingDisabledViolation(ctx.client, sessionID, failedMsg)
       } else if (errorType === "empty_content_message") {

src/hooks/session-recovery/storage.ts

@@ -154,13 +154,9 @@ export function findMessagesWithThinkingBlocks(sessionID: string): string[] {
   const messages = readMessages(sessionID)
   const result: string[] = []
 
-  for (let i = 0; i < messages.length; i++) {
+  for (const msg of messages) {
-    const msg = messages[i]
     if (msg.role !== "assistant") continue
 
-    const isLastMessage = i === messages.length - 1
-    if (isLastMessage) continue
-
     const parts = readParts(msg.id)
     const hasThinking = parts.some((p) => THINKING_TYPES.has(p.type))
     if (hasThinking) {
@@ -179,8 +175,8 @@ export function findMessagesWithOrphanThinking(sessionID: string): string[] {
     const msg = messages[i]
     if (msg.role !== "assistant") continue
 
-    const isLastMessage = i === messages.length - 1
+    // NOTE: Removed isLastMessage skip - recovery needs to fix last message too
-    if (isLastMessage) continue
+    // when "thinking must start with" errors occur on final assistant message
 
     const parts = readParts(msg.id)
     if (parts.length === 0) continue
@@ -188,10 +184,11 @@ export function findMessagesWithOrphanThinking(sessionID: string): string[] {
     const sortedParts = [...parts].sort((a, b) => a.id.localeCompare(b.id))
     const firstPart = sortedParts[0]
 
-    const hasThinking = parts.some((p) => THINKING_TYPES.has(p.type))
     const firstIsThinking = THINKING_TYPES.has(firstPart.type)
 
-    if (hasThinking && !firstIsThinking) {
+    // NOTE: Changed condition - if first part is not thinking, it's orphan
+    // regardless of whether thinking blocks exist elsewhere in the message
+    if (!firstIsThinking) {
       result.push(msg.id)
     }
   }
@@ -246,3 +243,25 @@ export function stripThinkingParts(messageID: string): boolean {
 
   return anyRemoved
 }
+
+export function findMessageByIndexNeedingThinking(sessionID: string, targetIndex: number): string | null {
+  const messages = readMessages(sessionID)
+
+  if (targetIndex < 0 || targetIndex >= messages.length) return null
+
+  const targetMsg = messages[targetIndex]
+  if (targetMsg.role !== "assistant") return null
+
+  const parts = readParts(targetMsg.id)
+  if (parts.length === 0) return null
+
+  const sortedParts = [...parts].sort((a, b) => a.id.localeCompare(b.id))
+  const firstPart = sortedParts[0]
+  const firstIsThinking = THINKING_TYPES.has(firstPart.type)
+
+  if (!firstIsThinking) {
+    return targetMsg.id
+  }
+
+  return null
+}