Probe for @ mentions in TUI append to prompt command

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

@@ -92,7 +92,33 @@ export function Prompt(props: PromptProps) {
   let promptPartTypeId: number
 
   sdk.event.on(TuiEvent.PromptAppend.type, (evt) => {
+    const oldLength = input.plainText.length
     input.insertText(evt.properties.text)
+
+    if (evt.properties.parts.length > 0) {
+      for (const part of evt.properties.parts) {
+        const extmarkId =
+          part.source &&
+          input.extmarks.create({
+            start: oldLength + (part.type === "file" ? part.source.text.start : part.source.start),
+            end: oldLength + (part.type === "file" ? part.source.text.end : part.source.end),
+            virtual: true,
+            styleId: part.type === "agent" ? agentStyleId : fileStyleId,
+            typeId: promptPartTypeId,
+          })
+
+        setStore(
+          produce((draft) => {
+            const partIndex = draft.prompt.parts.length
+            draft.prompt.parts.push(part)
+            if (extmarkId !== undefined) {
+              draft.extmarkToPartIndex.set(extmarkId, partIndex)
+            }
+          }),
+        )
+      }
+    }
+
     setTimeout(() => {
       input.getLayoutNode().markDirty()
       input.gotoBufferEnd()

packages/opencode/src/cli/cmd/tui/event.ts

@@ -1,9 +1,21 @@
 import { BusEvent } from "@/bus/bus-event"
 import { Bus } from "@/bus"
+import { MessageV2 } from "@/session/message-v2"
 import z from "zod"
 
 export const TuiEvent = {
-  PromptAppend: BusEvent.define("tui.prompt.append", z.object({ text: z.string() })),
+  PromptAppend: BusEvent.define(
+    "tui.prompt.append",
+    z.object({
+      text: z.string(),
+      parts: z.array(
+        z.union([
+          MessageV2.AgentPart.omit({ id: true, sessionID: true, messageID: true }),
+          MessageV2.FilePart.omit({ id: true, sessionID: true, messageID: true }),
+        ]),
+      ),
+    }),
+  ),
   CommandExecute: BusEvent.define(
     "tui.command.execute",
     z.object({

packages/opencode/src/server/server.ts

@@ -2442,10 +2442,25 @@ export namespace Server {
             ...errors(400),
           },
         }),
-        validator("json", TuiEvent.PromptAppend.properties),
+        validator("json", z.object({ text: z.string() })),
         async (c) => {
-          await Bus.publish(TuiEvent.PromptAppend, c.req.valid("json"))
-          return c.json(true)
+          const { text } = c.req.valid("json")
+
+          try {
+            await Bus.publish(TuiEvent.PromptAppend, {
+              text,
+              parts: (await SessionPrompt.resolvePromptParts(text)).filter(
+                (part) => part.type === "agent" || part.type === "file",
+              ),
+            })
+            return c.json(true)
+          } catch (error) {
+            log.error("Failed to process prompt append", {
+              text,
+              error: error instanceof Error ? error.message : String(error),
+            })
+            return c.json(false)
+          }
         },
       )
       .post(

packages/opencode/src/session/prompt.ts

@@ -185,6 +185,7 @@ export namespace SessionPrompt {
         text: template,
       },
     ]
+
     const files = ConfigMarkdown.files(template)
     const seen = new Set<string>()
     await Promise.all(
@@ -201,28 +202,32 @@ export namespace SessionPrompt {
           const agent = await Agent.get(name)
           if (agent) {
             parts.push({
-              type: "agent",
+              type: "agent" as const,
               name: agent.name,
+              source: {
+                start: match.index!,
+                end: match.index! + match[0].length,
+                value: match[0],
+              },
             })
           }
           return
         }
 
-        if (stats.isDirectory()) {
-          parts.push({
-            type: "file",
-            url: `file://${filepath}`,
-            filename: name,
-            mime: "application/x-directory",
-          })
-          return
-        }
-
         parts.push({
-          type: "file",
-          url: `file://${filepath}`,
+          type: "file" as const,
+          mime: stats.isDirectory() ? "application/x-directory" : "text/plain",
           filename: name,
-          mime: "text/plain",
+          url: `file://${filepath}`,
+          source: {
+            type: "file" as const,
+            path: name,
+            text: {
+              start: match.index!,
+              end: match.index! + match[0].length,
+              value: match[0],
+            },
+          },
         })
       }),
     )

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

@@ -615,6 +615,24 @@ export type EventTuiPromptAppend = {
   type: "tui.prompt.append"
   properties: {
     text: string
+    parts: Array<
+      | {
+          type: "agent"
+          name: string
+          source?: {
+            value: string
+            start: number
+            end: number
+          }
+        }
+      | {
+          type: "file"
+          mime: string
+          filename?: string
+          url: string
+          source?: FilePartSource
+        }
+    >
   }
 }