run: add shell mode to prompt (#28315)

Press `!` on an empty prompt to enter shell mode and run a command
through session.shell instead of sending a message

packages/opencode/src/cli/cmd/run/stream.transport.ts

@@ -132,6 +132,8 @@ function sid(event: Event): string | undefined {
   }
 
   if (
+    event.type === "session.next.shell.started" ||
+    event.type === "session.next.shell.ended" ||
     event.type === "permission.asked" ||
     event.type === "permission.replied" ||
     event.type === "question.asked" ||
@@ -513,6 +515,22 @@ function createLayer(input: StreamInput) {
           state.footerView = current
         }
 
+        const resolveShellAgent = Effect.fn("RunStreamTransport.resolveShellAgent")(function* (agent: string | undefined) {
+          if (agent) {
+            return agent
+          }
+
+          const list = yield* Effect.promise(() =>
+            input.sdk.app.agents(input.directory ? { directory: input.directory } : undefined, { throwOnError: true }),
+          ).pipe(Effect.map((item) => item.data ?? []), Effect.orElseSucceed(() => []))
+          const next = list.find((item) => item.mode !== "subagent" && item.hidden !== true)?.name
+          if (next) {
+            return next
+          }
+
+          return yield* Effect.fail(new Error("no primary agent available for shell mode"))
+        })
+
         const recoverQuestion = Effect.fn("RunStreamTransport.recoverQuestion")(function* (partID: string) {
           if (recovering.has(partID)) {
             return
@@ -1005,7 +1023,46 @@ function createLayer(input: StreamInput) {
             ],
           }
           const command = next.prompt.command
-          const send = command
+          const send = next.prompt.mode === "shell"
+            ? Effect.sync(() => {
+                input.trace?.write("send.shell", {
+                  sessionID: input.sessionID,
+                  command: next.prompt.text,
+                })
+              }).pipe(
+                Effect.andThen(
+                  resolveShellAgent(next.agent).pipe(
+                    Effect.flatMap((agent) =>
+                      Effect.promise(() =>
+                        input.sdk.session.shell(
+                          {
+                            sessionID: input.sessionID,
+                            agent,
+                            model: next.model,
+                            command: next.prompt.text,
+                          },
+                          { signal: turn.signal, throwOnError: true },
+                        ),
+                      ),
+                    ),
+                  ).pipe(
+                    Effect.tap(() =>
+                      Effect.sync(() => {
+                        input.trace?.write("send.shell.ok", {
+                          sessionID: input.sessionID,
+                        })
+                        item.armed = true
+                        item.live = true
+                      }),
+                    ),
+                    Effect.flatMap(() => Deferred.succeed(item.done, undefined).pipe(Effect.ignore)),
+                    Effect.catch((error) => Deferred.fail(item.done, error).pipe(Effect.ignore)),
+                    Effect.forkIn(scope, { startImmediately: true }),
+                    Effect.asVoid,
+                  ),
+                ),
+              )
+            : command
             ? Effect.sync(() => {
                 input.trace?.write("send.command", { sessionID: input.sessionID, command: command.name })
               }).pipe(