feat: subagent prompting and /finished command

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

@@ -258,6 +258,7 @@ export function Autocomplete(props: {
     const results: AutocompleteOption[] = []
     const s = session()
     for (const command of sync.data.command) {
+      if (command.name === "finished") continue
       results.push({
         display: "/" + command.name + (command.mcp ? " (MCP)" : ""),
         description: command.description,
@@ -271,6 +272,13 @@ export function Autocomplete(props: {
       })
     }
     if (s) {
+      if (s.parentID) {
+        results.push({
+          display: "/finished",
+          description: "summarize work and return to parent session",
+          onSelect: () => command.trigger("session.finished"),
+        })
+      }
       results.push(
         {
           display: "/undo",

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -69,6 +69,7 @@ import { Filesystem } from "@/util/filesystem"
 import { PermissionPrompt } from "./permission"
 import { DialogExportOptions } from "../../ui/dialog-export-options"
 import { formatTranscript } from "../../util/transcript"
+import { Identifier } from "@/id/id"
 
 addDefaultParsers(parsers.parsers)
 
@@ -357,6 +358,58 @@ export function Session() {
         dialog.clear()
       },
     },
+    {
+      title: "Finish subtask",
+      value: "session.finished",
+      category: "Session",
+      onSelect: (dialog) => {
+        const selectedModel = local.model.current()
+        if (!selectedModel) {
+          toast.show({
+            variant: "warning",
+            message: "Connect a provider to finish this session",
+            duration: 3000,
+          })
+          return
+        }
+        sdk.client.session.command({
+          sessionID: route.sessionID,
+          command: "finished",
+          arguments: "",
+          agent: local.agent.current().name,
+          model: `${selectedModel.providerID}/${selectedModel.modelID}`,
+          messageID: Identifier.ascending("message"),
+          variant: local.model.variant.current(),
+        })
+        dialog.clear()
+      },
+    },
+    {
+      title: "Finish subtask",
+      value: "session.finished",
+      category: "Session",
+      onSelect: (dialog) => {
+        const selectedModel = local.model.current()
+        if (!selectedModel) {
+          toast.show({
+            variant: "warning",
+            message: "Connect a provider to finish this session",
+            duration: 3000,
+          })
+          return
+        }
+        sdk.client.session.command({
+          sessionID: route.sessionID,
+          command: "finished",
+          arguments: "",
+          agent: local.agent.current().name,
+          model: `${selectedModel.providerID}/${selectedModel.modelID}`,
+          messageID: Identifier.ascending("message"),
+          variant: local.model.variant.current(),
+        })
+        dialog.clear()
+      },
+    },
     {
       title: "Unshare session",
       value: "session.unshare",
@@ -1025,7 +1078,7 @@ export function Session() {
                 <PermissionPrompt request={permissions()[0]} />
               </Show>
               <Prompt
-                visible={!session().parentID && permissions().length === 0}
+                visible={permissions().length === 0}
                 ref={(r) => {
                   prompt = r
                   promptRef.set(r)

packages/opencode/src/command/index.ts

@@ -53,6 +53,7 @@ export namespace Command {
   export const Default = {
     INIT: "init",
     REVIEW: "review",
+    FINISHED: "finished",
   } as const
 
   const state = Instance.state(async () => {
@@ -76,6 +77,12 @@ export namespace Command {
         subtask: true,
         hints: hints(PROMPT_REVIEW),
       },
+      [Default.FINISHED]: {
+        name: Default.FINISHED,
+        description: "summarize work and return to parent session",
+        template: "Summarize the work done in this session so far and finish the task.",
+        hints: [],
+      },
     }
 
     for (const [name, command] of Object.entries(cfg.command ?? {})) {

packages/opencode/src/session/prompt.ts

@@ -1466,6 +1466,22 @@ export namespace SessionPrompt {
       variant: input.variant,
     })) as MessageV2.WithParts
 
+    if (input.command === "finished") {
+      const session = await Session.get(input.sessionID)
+      if (session.parentID) {
+        const text = result.parts.findLast((x) => x.type === "text")?.text ?? ""
+        await prompt({
+          sessionID: session.parentID,
+          parts: [
+            {
+              type: "text",
+              text: `Subtask finished with the following summary:\n\n${text}\n\nSession: ${session.id}`,
+            },
+          ],
+        })
+      }
+    }
+
     Bus.publish(Command.Event.Executed, {
       name: input.command,
       sessionID: input.sessionID,