tui: improve agent selection and prompt editing experience

- Filter out built-in agents from autocomplete to show only custom agents
- Add proper agent part handling when selecting agents from autocomplete
- Fix cursor positioning and part management when editing prompts with agents

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

@@ -105,17 +105,28 @@ export function Autocomplete(props: {
   const agents = createMemo(() => {
     if (store.index !== 0) return []
     const agents = sync.data.agent
-    return agents.map(
-      (agent): AutocompleteOption => ({
-        display: "@" + agent.name,
-        onSelect: () => {
-          props.setPrompt((draft) => {
-            const append = "@" + agent.name + " "
-            draft.input = append
-          })
-        },
-      }),
-    )
+    return agents
+      .filter((agent) => !agent.builtIn && agent.mode !== "primary")
+      .map(
+        (agent): AutocompleteOption => ({
+          display: "@" + agent.name,
+          onSelect: () => {
+            props.setPrompt((draft) => {
+              const append = "@" + agent.name + " "
+              draft.input = append
+              draft.parts.push({
+                type: "agent",
+                source: {
+                  start: store.index,
+                  end: store.index + agent.name.length + 1,
+                  value: "@" + agent.name,
+                },
+                name: agent.name,
+              })
+            })
+          },
+        }),
+      )
   })
 
   const session = createMemo(() => (props.sessionID ? sync.session.get(props.sessionID) : undefined))

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

@@ -5,11 +5,11 @@ import { createStore, produce } from "solid-js/store"
 import { clone } from "remeda"
 import { createSimpleContext } from "../../context/helper"
 import { appendFile } from "fs/promises"
-import type { FilePart } from "@opencode-ai/sdk"
+import type { AgentPart, FilePart } from "@opencode-ai/sdk"
 
 export type PromptInfo = {
   input: string
-  parts: Omit<FilePart, "id" | "messageID" | "sessionID">[]
+  parts: (Omit<FilePart, "id" | "messageID" | "sessionID"> | Omit<AgentPart, "id" | "messageID" | "sessionID">)[]
 }
 
 export const { use: usePromptHistory, provider: PromptHistoryProvider } = createSimpleContext({

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

@@ -12,6 +12,7 @@ import { useKeybind } from "@tui/context/keybind"
 import { Clipboard } from "@/util/clipboard"
 import { usePromptHistory, type PromptInfo } from "./history"
 import { type AutocompleteRef, Autocomplete } from "./autocomplete"
+import { iife } from "@/util/iife"
 
 export type PromptProps = {
   sessionID?: string
@@ -113,17 +114,17 @@ export function Prompt(props: PromptProps) {
                     for (let i = 0; i < draft.parts.length; i++) {
                       const part = draft.parts[i]
                       if (!part.source) continue
-                      if (part.source.text.start >= input.cursorPosition) {
-                        part.source.text.start += diff
-                        part.source.text.end += diff
+                      const source = part.type === "agent" ? part.source : part.source.text
+                      if (source.start >= input.cursorPosition) {
+                        source.start += diff
+                        source.end += diff
                       }
-                      const sliced = draft.input.slice(part.source.text.start, part.source.text.end)
-                      if (sliced != part.source.text.value && diff < 0) {
-                        diff -= part.source.text.value.length
-                        draft.input =
-                          draft.input.slice(0, part.source.text.start) + draft.input.slice(part.source.text.end)
+                      const sliced = draft.input.slice(source.start, source.end)
+                      if (sliced != source.value && diff < 0) {
+                        diff -= source.value.length
+                        draft.input = draft.input.slice(0, source.start) + draft.input.slice(source.end)
                         draft.parts.splice(i, 1)
-                        input.cursorPosition = Math.max(0, part.source.text.start - 1)
+                        input.cursorPosition = Math.max(0, source.start - 1)
                         i--
                       }
                     }
@@ -160,13 +161,18 @@ export function Prompt(props: PromptProps) {
                   const position = input.cursorPosition
                   const direction = Math.sign(old - position)
                   for (const part of store.parts) {
-                    if (part.source && part.source.type === "file") {
-                      if (position >= part.source.text.start && position < part.source.text.end) {
+                    const source = iife(() => {
+                      if (part.type === "agent") return part.source
+                      if (part.type === "file") return part.source?.text
+                      return
+                    })
+                    if (source) {
+                      if (position >= source.start && position < source.end) {
                         if (direction === 1) {
-                          input.cursorPosition = Math.max(0, part.source.text.start - 1)
+                          input.cursorPosition = Math.max(0, source.start - 1)
                         }
                         if (direction === -1) {
-                          input.cursorPosition = part.source.text.end
+                          input.cursorPosition = source.end
                         }
                       }
                     }