fix(session): use index-based message ordering and harden prompt loop exit

packages/app/src/components/session/session-context-tab.tsx

@@ -3,6 +3,7 @@ import type { JSX } from "solid-js"
 import { useSync } from "@/context/sync"
 import { checksum } from "@opencode-ai/util/encode"
 import { findLast } from "@opencode-ai/util/array"
+import { sortMessages } from "@opencode-ai/util/message"
 import { same } from "@/utils/same"
 import { Icon } from "@opencode-ai/ui/icon"
 import { Accordion } from "@opencode-ai/ui/accordion"
@@ -100,7 +101,7 @@ export function SessionContextTab() {
     () => {
       const id = params.id
       if (!id) return emptyMessages
-      return (sync.data.message[id] ?? []) as Message[]
+      return sortMessages((sync.data.message[id] ?? []) as Message[])
     },
     emptyMessages,
     { equals: same },

packages/app/src/pages/session.tsx

@@ -411,7 +411,8 @@ export default function Page() {
     () => {
       const revert = revertMessageID()
       if (!revert) return userMessages()
-      return userMessages().filter((m) => m.id < revert)
+      const idx = userMessages().findIndex((m) => m.id === revert)
+      return idx >= 0 ? userMessages().slice(0, idx) : userMessages()
     },
     emptyUserMessages,
     {
@@ -569,7 +570,7 @@ export default function Page() {
       )
       return
     }
-    const at = list.findIndex((item) => item.id > next.id)
+    const at = list.findIndex((item) => item.id.localeCompare(next.id) > 0)
     if (at >= 0) {
       globalSync.set("project", [...list.slice(0, at), next, ...list.slice(at)])
       return
@@ -1245,7 +1246,8 @@ export default function Page() {
     const sessionID = params.id
     if (!sessionID || ui.restoring) return
 
-    const next = userMessages().find((item) => item.id > id)
+    const idx = userMessages().findIndex((m) => m.id === id)
+    const next = idx >= 0 ? userMessages()[idx + 1] : undefined
     setUi("restoring", id)
 
     const task = !next
@@ -1273,9 +1275,8 @@ export default function Page() {
   const rolled = createMemo(() => {
     const id = revertMessageID()
     if (!id) return []
-    return userMessages()
-      .filter((item) => item.id >= id)
-      .map((item) => ({ id: item.id, text: line(item.id) }))
+    const idx = userMessages().findIndex((m) => m.id === id)
+    return (idx >= 0 ? userMessages().slice(idx) : []).map((item) => ({ id: item.id, text: line(item.id) }))
   })
 
   const actions = { fork, revert }

packages/app/src/pages/session/message-timeline.tsx

@@ -13,7 +13,7 @@ import { SessionTurn } from "@opencode-ai/ui/session-turn"
 import { ScrollView } from "@opencode-ai/ui/scroll-view"
 import type { AssistantMessage, Message as MessageType, Part, TextPart, UserMessage } from "@opencode-ai/sdk/v2"
 import { showToast } from "@opencode-ai/ui/toast"
-import { Binary } from "@opencode-ai/util/binary"
+import { sortMessages } from "@opencode-ai/util/message"
 import { getFilename } from "@opencode-ai/util/path"
 import { shouldMarkBoundaryGesture, normalizeWheelDelta } from "@/pages/session/message-gesture"
 import { SessionContextUsage } from "@/components/session-context-usage"
@@ -227,7 +227,7 @@ export function MessageTimeline(props: {
   const sessionMessages = createMemo(() => {
     const id = sessionID()
     if (!id) return emptyMessages
-    return sync.data.message[id] ?? emptyMessages
+    return sortMessages(sync.data.message[id] ?? emptyMessages)
   })
   const pending = createMemo(() =>
     sessionMessages().findLast(
@@ -277,8 +277,7 @@ export function MessageTimeline(props: {
     const parentID = pending()?.parentID
     if (parentID) {
       const messages = sessionMessages()
-      const result = Binary.search(messages, parentID, (message) => message.id)
-      const message = result.found ? messages[result.index] : messages.find((item) => item.id === parentID)
+      const message = messages.find((item) => item.id === parentID)
       if (message && message.role === "user") return message.id
     }
 
@@ -755,8 +754,11 @@ export function MessageTimeline(props: {
                   const queued = createMemo(() => {
                     if (active()) return false
                     const activeID = activeMessageID()
-                    if (activeID) return messageID > activeID
-                    return false
+                    if (!activeID) return false
+                    const ids = rendered()
+                    const activeIdx = ids.indexOf(activeID)
+                    if (activeIdx === -1) return false
+                    return ids.indexOf(messageID) > activeIdx
                   })
                   const comments = createMemo(() => messageComments(sync.data.part[messageID] ?? []), [], {
                     equals: (a, b) => JSON.stringify(a) === JSON.stringify(b),

packages/app/src/pages/session/use-session-commands.tsx

@@ -18,6 +18,7 @@ import { DialogSelectMcp } from "@/components/dialog-select-mcp"
 import { DialogFork } from "@/components/dialog-fork"
 import { showToast } from "@opencode-ai/ui/toast"
 import { findLast } from "@opencode-ai/util/array"
+import { sortMessages } from "@opencode-ai/util/message"
 import { extractPromptFromParts } from "@/utils/prompt"
 import { UserMessage } from "@opencode-ai/sdk/v2"
 import { useSessionLayout } from "@/pages/session/session-layout"
@@ -54,7 +55,7 @@ export const useSessionCommands = (actions: SessionCommandContext) => {
 
   const idle = { type: "idle" as const }
   const status = createMemo(() => sync.data.session_status[params.id ?? ""] ?? idle)
-  const messages = createMemo(() => (params.id ? (sync.data.message[params.id] ?? []) : []))
+  const messages = createMemo(() => sortMessages(params.id ? (sync.data.message[params.id] ?? []) : []))
   const userMessages = createMemo(() => messages().filter((m) => m.role === "user") as UserMessage[])
   const visibleUserMessages = createMemo(() => {
     const revert = info()?.revert?.messageID

packages/opencode/src/session/index.ts

@@ -252,9 +252,11 @@ export namespace Session {
       })
       const msgs = await messages({ sessionID: input.sessionID })
       const idMap = new Map<string, MessageID>()
+      const cutoff = input.messageID ? msgs.findIndex((msg) => msg.info.id === input.messageID) : -1
 
-      for (const msg of msgs) {
-        if (input.messageID && msg.info.id >= input.messageID) break
+      for (let i = 0; i < msgs.length; i++) {
+        if (cutoff >= 0 && i >= cutoff) break
+        const msg = msgs[i]
         const newID = MessageID.ascending()
         idMap.set(msg.info.id, newID)
 

packages/opencode/src/session/message-v2.ts

@@ -616,6 +616,14 @@ export namespace MessageV2 {
         ) {
           continue
         }
+        // Skip incomplete assistant messages (no finish, no error, and no meaningful parts)
+        if (
+          !msg.info.finish &&
+          !msg.info.error &&
+          !msg.parts.some((part) => part.type !== "step-start")
+        ) {
+          continue
+        }
         const assistantMessage: UIMessage = {
           id: msg.info.id,
           role: "assistant",

packages/opencode/src/session/prompt.ts

@@ -300,15 +300,16 @@ export namespace SessionPrompt {
       let msgs = await MessageV2.filterCompacted(MessageV2.stream(sessionID))
 
       let lastUser: MessageV2.User | undefined
-      let lastAssistant: MessageV2.Assistant | undefined
       let lastFinished: MessageV2.Assistant | undefined
+      let finishedIdx = -1
       let tasks: (MessageV2.CompactionPart | MessageV2.SubtaskPart)[] = []
       for (let i = msgs.length - 1; i >= 0; i--) {
         const msg = msgs[i]
         if (!lastUser && msg.info.role === "user") lastUser = msg.info as MessageV2.User
-        if (!lastAssistant && msg.info.role === "assistant") lastAssistant = msg.info as MessageV2.Assistant
-        if (!lastFinished && msg.info.role === "assistant" && msg.info.finish)
+        if (!lastFinished && msg.info.role === "assistant" && msg.info.finish) {
           lastFinished = msg.info as MessageV2.Assistant
+          finishedIdx = i
+        }
         if (lastUser && lastFinished) break
         const task = msg.parts.filter((part) => part.type === "compaction" || part.type === "subtask")
         if (task && !lastFinished) {
@@ -317,11 +318,7 @@ export namespace SessionPrompt {
       }
 
       if (!lastUser) throw new Error("No user message found in stream. This should never happen.")
-      if (
-        lastAssistant?.finish &&
-        !["tool-calls", "unknown"].includes(lastAssistant.finish) &&
-        lastUser.id < lastAssistant.id
-      ) {
+      if (shouldExitLoop(lastUser, lastFinished)) {
         log.info("exiting loop", { sessionID })
         break
       }
@@ -631,8 +628,9 @@ export namespace SessionPrompt {
 
       // Ephemerally wrap queued user messages with a reminder to stay on track
       if (step > 1 && lastFinished) {
-        for (const msg of msgs) {
-          if (msg.info.role !== "user" || msg.info.id <= lastFinished.id) continue
+        for (let i = 0; i < msgs.length; i++) {
+          const msg = msgs[i]
+          if (!shouldWrapSystemReminder(msg.info, i, lastFinished, finishedIdx)) continue
           for (const part of msg.parts) {
             if (part.type !== "text" || part.ignored || part.synthetic) continue
             if (!part.text.trim()) continue
@@ -1966,4 +1964,26 @@ NOTE: At any point in time through this workflow you should feel free to ask the
       return Session.setTitle({ sessionID: input.session.id, title })
     }
   }
+
+  export function shouldExitLoop(
+    lastUser: MessageV2.User | undefined,
+    lastAssistant: MessageV2.Assistant | undefined,
+  ): boolean {
+    if (!lastUser) return false
+    if (!lastAssistant?.finish) return false
+    if (["tool-calls", "unknown"].includes(lastAssistant.finish)) return false
+    if (!lastAssistant.parentID) return true
+    return lastAssistant.parentID === lastUser.id
+  }
+
+  export function shouldWrapSystemReminder(
+    msg: MessageV2.User | MessageV2.Assistant,
+    idx: number,
+    lastFinished: MessageV2.Assistant | undefined,
+    finishedIdx: number,
+  ): boolean {
+    if (msg.role !== "user") return false
+    if (!lastFinished) return false
+    return idx > finishedIdx
+  }
 }

packages/opencode/src/session/revert.ts

@@ -59,7 +59,8 @@ export namespace SessionRevert {
       revert.snapshot = session.revert?.snapshot ?? (await Snapshot.track())
       await Snapshot.revert(patches)
       if (revert.snapshot) revert.diff = await Snapshot.diff(revert.snapshot)
-      const rangeMessages = all.filter((msg) => msg.info.id >= revert!.messageID)
+      const idx = all.findIndex((msg) => msg.info.id === revert!.messageID)
+      const rangeMessages = idx >= 0 ? all.slice(idx) : all
       const diffs = await SessionSummary.computeDiff({ messages: rangeMessages })
       await Storage.write(["session_diff", input.sessionID], diffs)
       Bus.publish(Session.Event.Diff, {
@@ -96,21 +97,27 @@ export namespace SessionRevert {
     const preserve = [] as MessageV2.WithParts[]
     const remove = [] as MessageV2.WithParts[]
     let target: MessageV2.WithParts | undefined
-    for (const msg of msgs) {
-      if (msg.info.id < messageID) {
-        preserve.push(msg)
-        continue
-      }
-      if (msg.info.id > messageID) {
+    const idx = msgs.findIndex((msg) => msg.info.id === messageID)
+    if (idx < 0) {
+      preserve.push(...msgs)
+    } else {
+      for (let i = 0; i < msgs.length; i++) {
+        const msg = msgs[i]!
+        if (i < idx) {
+          preserve.push(msg)
+          continue
+        }
+        if (i > idx) {
+          remove.push(msg)
+          continue
+        }
+        if (session.revert.partID) {
+          preserve.push(msg)
+          target = msg
+          continue
+        }
         remove.push(msg)
-        continue
-      }
-      if (session.revert.partID) {
-        preserve.push(msg)
-        target = msg
-        continue
       }
-      remove.push(msg)
     }
     for (const msg of remove) {
       Database.use((db) => db.delete(MessageTable).where(eq(MessageTable.id, msg.info.id)).run())

packages/opencode/test/session/fixtures/skewed-messages.ts

@@ -0,0 +1,84 @@
+import { Identifier } from "../../../src/id/id"
+import { MessageV2 } from "../../../src/session/message-v2"
+import { MessageID, SessionID } from "../../../src/session/schema"
+import { ModelID, ProviderID } from "../../../src/provider/schema"
+
+export function makeUser(
+  id: MessageID,
+  opts?: Partial<MessageV2.User>,
+): MessageV2.User {
+  return {
+    id,
+    sessionID: SessionID.make("test-session"),
+    role: "user",
+    time: { created: Date.now() },
+    agent: "default",
+    model: {
+      providerID: ProviderID.openai,
+      modelID: ModelID.make("gpt-4"),
+    },
+    ...opts,
+  }
+}
+
+export function makeAssistant(
+  id: MessageID,
+  parentID: MessageID,
+  opts?: Partial<MessageV2.Assistant>,
+): MessageV2.Assistant {
+  return {
+    id,
+    sessionID: SessionID.make("test-session"),
+    role: "assistant",
+    parentID,
+    time: { created: Date.now() },
+    modelID: ModelID.make("gpt-4"),
+    providerID: ProviderID.openai,
+    mode: "default",
+    agent: "default",
+    path: {
+      cwd: "/tmp",
+      root: "/tmp",
+    },
+    cost: 0,
+    tokens: {
+      input: 0,
+      output: 0,
+      reasoning: 0,
+      cache: {
+        read: 0,
+        write: 0,
+      },
+    },
+    finish: "stop",
+    ...opts,
+  }
+}
+
+export function aheadPair(): {
+  user: MessageV2.User
+  assistant: MessageV2.Assistant
+} {
+  const now = Date.now()
+  const userID = MessageID.make(Identifier.create("message", false, now + 60_000))
+  const assistantID = MessageID.make(Identifier.create("message", false, now))
+
+  return {
+    user: makeUser(userID),
+    assistant: makeAssistant(assistantID, userID),
+  }
+}
+
+export function behindPair(): {
+  user: MessageV2.User
+  assistant: MessageV2.Assistant
+} {
+  const now = Date.now()
+  const userID = MessageID.make(Identifier.create("message", false, now - 60_000))
+  const assistantID = MessageID.make(Identifier.create("message", false, now))
+
+  return {
+    user: makeUser(userID),
+    assistant: makeAssistant(assistantID, userID),
+  }
+}