fix(tui): remove feature flag, fix stale suggestion, limit to 110 chars

- Remove OPENCODE_EXPERIMENTAL_NEXT_PROMPT gate so suggest always runs
- Use reconcile() in sync store to clear stale suggestion on status change
- Limit suggestion to 110 characters and instruct model to be concise
- Remove temporary debug sidebar panel and plumbing

packages/opencode/src/cli/cmd/tui/app.tsx

@@ -128,7 +128,6 @@ function rendererConfig(_config: TuiConfig.Info): CliRendererConfig {
   const mouseEnabled = !Flag.OPENCODE_DISABLE_MOUSE && (_config.mouse ?? true)
 
   return {
-    externalOutputMode: "passthrough",
     targetFps: 60,
     gatherStats: false,
     exitOnCtrlC: false,

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -841,8 +841,20 @@ export function Prompt(props: PromptProps) {
     return !!current
   })
 
+  const suggestion = createMemo(() => {
+    if (!props.sessionID) return
+    if (store.mode !== "normal") return
+    if (store.prompt.input) return
+    const current = status()
+    if (current.type !== "idle") return
+    const value = current.suggestion?.trim()
+    if (!value) return
+    return value
+  })
+
   const placeholderText = createMemo(() => {
     if (props.showPlaceholder === false) return undefined
+    if (suggestion()) return suggestion()
     if (store.mode === "shell") {
       if (!shell().length) return undefined
       const example = shell()[store.placeholder % shell().length]
@@ -933,6 +945,16 @@ export function Prompt(props: PromptProps) {
                   e.preventDefault()
                   return
                 }
+                if (!store.prompt.input && e.name === "right" && !e.ctrl && !e.meta && !e.shift && !e.super) {
+                  const value = suggestion()
+                  if (value) {
+                    input.setText(value)
+                    setStore("prompt", "input", value)
+                    input.gotoBufferEnd()
+                    e.preventDefault()
+                    return
+                  }
+                }
                 // Check clipboard for images before terminal-handled paste runs.
                 // This helps terminals that forward Ctrl+V to the app; Windows
                 // Terminal 1.25+ usually handles Ctrl+V before this path.

packages/opencode/src/cli/cmd/tui/context/sync.tsx

@@ -233,7 +233,7 @@ export const { use: useSync, provider: SyncProvider } = createSimpleContext({
         }
 
         case "session.status": {
-          setStore("session_status", event.properties.sessionID, event.properties.status)
+          setStore("session_status", event.properties.sessionID, reconcile(event.properties.status))
           break
         }
 

packages/opencode/src/flag/flag.ts

@@ -73,6 +73,7 @@ export namespace Flag {
   export const OPENCODE_EXPERIMENTAL_PLAN_MODE = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_PLAN_MODE")
   export const OPENCODE_EXPERIMENTAL_WORKSPACES = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_WORKSPACES")
   export const OPENCODE_EXPERIMENTAL_MARKDOWN = !falsy("OPENCODE_EXPERIMENTAL_MARKDOWN")
+  export const OPENCODE_EXPERIMENTAL_NEXT_PROMPT = truthy("OPENCODE_EXPERIMENTAL_NEXT_PROMPT")
   export const OPENCODE_MODELS_URL = process.env["OPENCODE_MODELS_URL"]
   export const OPENCODE_MODELS_PATH = process.env["OPENCODE_MODELS_PATH"]
   export const OPENCODE_DISABLE_EMBEDDED_WEB_UI = truthy("OPENCODE_DISABLE_EMBEDDED_WEB_UI")

packages/opencode/src/session/prompt.ts

@@ -20,6 +20,7 @@ import { Plugin } from "../plugin"
 import PROMPT_PLAN from "../session/prompt/plan.txt"
 import BUILD_SWITCH from "../session/prompt/build-switch.txt"
 import MAX_STEPS from "../session/prompt/max-steps.txt"
+import PROMPT_SUGGEST_NEXT from "../session/prompt/suggest-next.txt"
 import { ToolRegistry } from "../tool/registry"
 import { Runner } from "@/effect/runner"
 import { MCP } from "../mcp"
@@ -249,6 +250,80 @@ export namespace SessionPrompt {
           )
       })
 
+      const suggest = Effect.fn("SessionPrompt.suggest")(function* (input: {
+        session: Session.Info
+        sessionID: SessionID
+        message: MessageV2.WithParts
+      }) {
+        if (input.session.parentID) return
+        const message = input.message.info
+        if (message.role !== "assistant") return
+        if (message.error) return
+        if (!message.finish) return
+        if (["tool-calls", "unknown"].includes(message.finish)) return
+        if ((yield* status.get(input.sessionID)).type !== "idle") return
+
+        // Use the same model for prompt-cache hit on the conversation prefix
+        const model = yield* Effect.promise(async () =>
+          Provider.getModel(message.providerID, message.modelID).catch(() => undefined),
+        )
+        if (!model) return
+
+        const ag = yield* agents.get(message.agent ?? "code")
+        if (!ag) return
+
+        // Full message history so the cached KV from the main conversation is reused
+        const msgs = yield* MessageV2.filterCompactedEffect(input.sessionID)
+        const real = (item: MessageV2.WithParts) =>
+          item.info.role === "user" && !item.parts.every((part) => "synthetic" in part && part.synthetic)
+        const parent = msgs.find((item) => item.info.id === message.parentID)
+        const user = parent && real(parent) ? parent.info : msgs.findLast((item) => real(item))?.info
+        if (!user || user.role !== "user") return
+
+        // Rebuild system prompt identical to the main loop for cache hit
+        const skills = yield* Effect.promise(() => SystemPrompt.skills(ag))
+        const env = yield* Effect.promise(() => SystemPrompt.environment(model))
+        const instructions = yield* instruction.system().pipe(Effect.orDie)
+        const modelMsgs = yield* Effect.promise(() => MessageV2.toModelMessages(msgs, model))
+        const system = [...env, ...(skills ? [skills] : []), ...instructions]
+
+        const text = yield* Effect.promise(async (signal) => {
+          const result = await LLM.stream({
+            agent: ag,
+            user,
+            system,
+            small: false,
+            tools: {},
+            model,
+            abort: signal,
+            sessionID: input.sessionID,
+            retries: 1,
+            toolChoice: "none",
+            // Append suggestion instruction after the full conversation
+            messages: [...modelMsgs, { role: "user" as const, content: PROMPT_SUGGEST_NEXT }],
+          })
+          return result.text
+        })
+
+        const line = text
+          .replace(/<think>[\s\S]*?<\/think>\s*/g, "")
+          .split("\n")
+          .map((item) => item.trim())
+          .find((item) => item.length > 0)
+          ?.replace(/^["'`]+|["'`]+$/g, "")
+        if (!line) return
+
+        const tag = line
+          .toUpperCase()
+          .replace(/[\s-]+/g, "_")
+          .replace(/[^A-Z_]/g, "")
+        if (tag === "NO_SUGGESTION") return
+
+        const suggestion = line.length > 110 ? line.slice(0, 107) + "..." : line
+        if ((yield* status.get(input.sessionID)).type !== "idle") return
+        yield* status.suggest(input.sessionID, suggestion)
+      })
+
       const insertReminders = Effect.fn("SessionPrompt.insertReminders")(function* (input: {
         messages: MessageV2.WithParts[]
         agent: Agent.Info
@@ -1319,7 +1394,13 @@ NOTE: At any point in time through this workflow you should feel free to ask the
           }
 
           if (input.noReply === true) return message
-          return yield* loop({ sessionID: input.sessionID })
+          const result = yield* loop({ sessionID: input.sessionID })
+          yield* suggest({
+            session,
+            sessionID: input.sessionID,
+            message: result,
+          }).pipe(Effect.ignore, Effect.forkIn(scope))
+          return result
         },
       )
 

packages/opencode/src/session/prompt/suggest-next.txt

@@ -0,0 +1,21 @@
+You are generating a suggested next user message for the current conversation.
+
+Goal:
+- Suggest a useful next step that keeps momentum.
+
+Rules:
+- Output exactly one line, 110 characters max. Be concise.
+- Write as the user speaking to the assistant (for example: "Can you...", "Help me...", "Let's...").
+- Match the user's tone and language; keep it natural and human.
+- Prefer a concrete action over a broad question.
+- If the conversation is vague or small-talk, steer toward a practical starter request.
+- If there is no meaningful or appropriate next step to suggest, output exactly: NO_SUGGESTION
+- Avoid corporate or robotic phrasing.
+- Avoid asking multiple discovery questions in one sentence.
+- Do not include quotes, labels, markdown, or explanations.
+
+Examples:
+- Greeting context -> "Can you scan this repo and suggest the best first task to tackle?"
+- Bug-fix context -> "Can you reproduce this bug and propose the smallest safe fix?"
+- Feature context -> "Let's implement this incrementally; start with the MVP version first."
+- Conversation is complete -> "NO_SUGGESTION"

packages/opencode/src/session/status.ts

@@ -11,6 +11,7 @@ export namespace SessionStatus {
     .union([
       z.object({
         type: z.literal("idle"),
+        suggestion: z.string().optional(),
       }),
       z.object({
         type: z.literal("retry"),
@@ -48,6 +49,7 @@ export namespace SessionStatus {
     readonly get: (sessionID: SessionID) => Effect.Effect<Info>
     readonly list: () => Effect.Effect<Map<SessionID, Info>>
     readonly set: (sessionID: SessionID, status: Info) => Effect.Effect<void>
+    readonly suggest: (sessionID: SessionID, suggestion: string) => Effect.Effect<void>
   }
 
   export class Service extends ServiceMap.Service<Service, Interface>()("@opencode/SessionStatus") {}
@@ -81,7 +83,17 @@ export namespace SessionStatus {
         data.set(sessionID, status)
       })
 
-      return Service.of({ get, list, set })
+      const suggest = Effect.fn("SessionStatus.suggest")(function* (sessionID: SessionID, suggestion: string) {
+        const data = yield* InstanceState.get(state)
+        const current = data.get(sessionID)
+        if (current && current.type !== "idle") return
+        const status: Info = { type: "idle", suggestion }
+        // only publish Status so the TUI sees the suggestion;
+        // skip Event.Idle to avoid spurious plugin notifications
+        yield* bus.publish(Event.Status, { sessionID, status })
+      })
+
+      return Service.of({ get, list, set, suggest })
     }),
   )
 
@@ -99,4 +111,8 @@ export namespace SessionStatus {
   export async function set(sessionID: SessionID, status: Info) {
     return runPromise((svc) => svc.set(sessionID, status))
   }
+
+  export async function suggest(sessionID: SessionID, suggestion: string) {
+    return runPromise((svc) => svc.suggest(sessionID, suggestion))
+  }
 }

packages/sdk/js/src/v2/gen/types.gen.ts

@@ -126,6 +126,7 @@ export type EventPermissionReplied = {
 export type SessionStatus =
   | {
       type: "idle"
+      suggestion?: string
     }
   | {
       type: "retry"