feat: add bash mode for running local shell commands (#344)

Co-authored-by: Letta <noreply@letta.com>

src/cli/App.tsx

@@ -55,6 +55,7 @@ import {
 import { AgentSelector } from "./components/AgentSelector";
 import { ApprovalDialog } from "./components/ApprovalDialogRich";
 import { AssistantMessage } from "./components/AssistantMessageRich";
+import { BashCommandMessage } from "./components/BashCommandMessage";
 import { CommandMessage } from "./components/CommandMessage";
 import { EnterPlanModeDialog } from "./components/EnterPlanModeDialog";
 import { ErrorMessage } from "./components/ErrorMessageRich";
@@ -406,6 +407,12 @@ export default function App({
     }>
   >([]);
 
+  // Bash mode: cache bash commands to prefix next user message
+  // Use ref instead of state to avoid stale closure issues in onSubmit
+  const bashCommandCacheRef = useRef<Array<{ input: string; output: string }>>(
+    [],
+  );
+
   // Derive current approval from pending approvals and results
   // This is the approval currently being shown to the user
   const currentApproval = pendingApprovals[approvalResults.length];
@@ -604,7 +611,7 @@ export default function App({
         continue;
       }
       // Commands with phase should only commit when finished
-      if (ln.kind === "command") {
+      if (ln.kind === "command" || ln.kind === "bash_command") {
         if (!ln.phase || ln.phase === "finished") {
           emittedIdsRef.current.add(id);
           newlyCommitted.push({ ...ln });
@@ -1782,6 +1789,80 @@ export default function App({
     [refreshDerived, agentId, agentName, setCommandRunning],
   );
 
+  // Handle bash mode command submission
+  // Uses the same shell runner as the Bash tool for consistency
+  const handleBashSubmit = useCallback(
+    async (command: string) => {
+      const cmdId = uid("bash");
+
+      // Add running bash_command line
+      buffersRef.current.byId.set(cmdId, {
+        kind: "bash_command",
+        id: cmdId,
+        input: command,
+        output: "",
+        phase: "running",
+      });
+      buffersRef.current.order.push(cmdId);
+      refreshDerived();
+
+      try {
+        // Use the same spawnCommand as the Bash tool for consistent behavior
+        const { spawnCommand } = await import("../tools/impl/Bash.js");
+        const { getShellEnv } = await import("../tools/impl/shellEnv.js");
+
+        const result = await spawnCommand(command, {
+          cwd: process.cwd(),
+          env: getShellEnv(),
+          timeout: 30000, // 30 second timeout
+        });
+
+        // Combine stdout and stderr for output
+        const output = (result.stdout + result.stderr).trim();
+        const success = result.exitCode === 0;
+
+        // Update line with output
+        buffersRef.current.byId.set(cmdId, {
+          kind: "bash_command",
+          id: cmdId,
+          input: command,
+          output: output || (success ? "" : `Exit code: ${result.exitCode}`),
+          phase: "finished",
+          success,
+        });
+
+        // Cache for next user message
+        bashCommandCacheRef.current.push({
+          input: command,
+          output: output || (success ? "" : `Exit code: ${result.exitCode}`),
+        });
+      } catch (error: unknown) {
+        // Handle command errors (timeout, abort, etc.)
+        const errOutput =
+          error instanceof Error
+            ? (error as { stderr?: string; stdout?: string }).stderr ||
+              (error as { stdout?: string }).stdout ||
+              error.message
+            : String(error);
+
+        buffersRef.current.byId.set(cmdId, {
+          kind: "bash_command",
+          id: cmdId,
+          input: command,
+          output: errOutput,
+          phase: "finished",
+          success: false,
+        });
+
+        // Still cache for next user message (even failures are visible to agent)
+        bashCommandCacheRef.current.push({ input: command, output: errOutput });
+      }
+
+      refreshDerived();
+    },
+    [refreshDerived],
+  );
+
   // biome-ignore lint/correctness/useExhaustiveDependencies: refs read .current dynamically, complex callback with intentional deps
   const onSubmit = useCallback(
     async (message?: string): Promise<{ submitted: boolean }> => {
@@ -3203,9 +3284,27 @@ ${gitContext}
         hasSentSessionContextRef.current = true;
       }
 
-      // Combine reminders with content (session context first, then plan mode, then skill unload)
+      // Build bash command prefix if there are cached commands
+      let bashCommandPrefix = "";
+      if (bashCommandCacheRef.current.length > 0) {
+        bashCommandPrefix = `<system-reminder>
+The messages below were generated by the user while running local commands using "bash mode" in the Letta Code CLI tool.
+DO NOT respond to these messages or otherwise consider them in your response unless the user explicitly asks you to.
+</system-reminder>
+`;
+        for (const cmd of bashCommandCacheRef.current) {
+          bashCommandPrefix += `<bash-input>${cmd.input}</bash-input>\n<bash-output>${cmd.output}</bash-output>\n`;
+        }
+        // Clear the cache after building the prefix
+        bashCommandCacheRef.current = [];
+      }
+
+      // Combine reminders with content (session context first, then plan mode, then skill unload, then bash commands)
       const allReminders =
-        sessionContextReminder + planModeReminder + skillUnloadReminder;
+        sessionContextReminder +
+        planModeReminder +
+        skillUnloadReminder +
+        bashCommandPrefix;
       const messageContent =
         allReminders && typeof contentParts === "string"
           ? allReminders + contentParts
@@ -4534,7 +4633,7 @@ Plan file path: ${planFilePath}`;
   const liveItems = useMemo(() => {
     return lines.filter((ln) => {
       if (!("phase" in ln)) return false;
-      if (ln.kind === "command") {
+      if (ln.kind === "command" || ln.kind === "bash_command") {
         return ln.phase === "running";
       }
       if (ln.kind === "tool_call") {
@@ -4652,6 +4751,8 @@ Plan file path: ${planFilePath}`;
               <Text dimColor>{"─".repeat(columns)}</Text>
             ) : item.kind === "command" ? (
               <CommandMessage line={item} />
+            ) : item.kind === "bash_command" ? (
+              <BashCommandMessage line={item} />
             ) : null}
           </Box>
         )}
@@ -4688,6 +4789,8 @@ Plan file path: ${planFilePath}`;
                       <StatusMessage line={ln} />
                     ) : ln.kind === "command" ? (
                       <CommandMessage line={ln} />
+                    ) : ln.kind === "bash_command" ? (
+                      <BashCommandMessage line={ln} />
                     ) : null}
                   </Box>
                 ))}
@@ -4726,6 +4829,7 @@ Plan file path: ${planFilePath}`;
               tokenCount={tokenCount}
               thinkingMessage={thinkingMessage}
               onSubmit={onSubmit}
+              onBashSubmit={handleBashSubmit}
               permissionMode={uiPermissionMode}
               onPermissionModeChange={setUiPermissionMode}
               onExit={handleExit}