fix(agent): fallback to fresh start when resume args fail

When a resumed agent exits with a non-zero code and the output indicates
a resume-args failure (e.g. Claude's \"No conversation found to continue\"),
automatically restart the agent without resume args instead of leaving it
in an exited state.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: 2 people

src/components/TaskAITerminal.tsx

@@ -30,7 +30,7 @@ import { createHighlightedMarkdown } from '../lib/marked-shiki';
 import type { Task } from '../store/types';
 import type { AgentDef } from '../ipc/types';
 import type { PromptInputHandle } from './PromptInput';
-import { buildTaskAgentArgs } from '../lib/agent-args';
+import { buildTaskAgentArgs, isResumeArgsFailure } from '../lib/agent-args';
 
 function aiTerminalPanelId(agentId: string): string {
   return `ai-terminal:${agentId}`;
@@ -614,7 +614,19 @@ function AgentTerminalPane(props: {
                 }
                 attachExisting={a().attachExisting}
                 preserveSessionOnCleanup
-                onExit={(code) => markAgentExited(a().id, code)}
+                onExit={(code) => {
+                  if (
+                    a().resumed &&
+                    code.exit_code !== 0 &&
+                    isResumeArgsFailure(a().def.command, code.last_output)
+                  ) {
+                    // Resume args failed (e.g. Claude's "No conversation to continue");
+                    // fall back to a fresh start with normal args.
+                    restartAgent(a().id, false);
+                    return;
+                  }
+                  markAgentExited(a().id, code);
+                }}
                 onData={(data) => markAgentOutput(a().id, data, props.task.id)}
                 onFileLink={props.onFileLink}
                 onPromptDetected={(text) => setLastPrompt(props.task.id, text)}

src/lib/agent-args.ts

@@ -9,6 +9,18 @@ function isAntigravityCommand(command: string): boolean {
   return command.split('/').pop() === 'agy';
 }
 
+const RESUME_FAILURE_PATTERNS: Record<string, string[]> = {
+  claude: ['No conversation found to continue'],
+};
+
+export function isResumeArgsFailure(command: string, lastOutput: string[]): boolean {
+  const base = command.split('/').pop() ?? command;
+  const patterns = RESUME_FAILURE_PATTERNS[base];
+  if (!patterns || lastOutput.length === 0) return false;
+  const text = lastOutput.join('\n');
+  return patterns.some((pattern) => text.includes(pattern));
+}
+
 function legacyMcpConfigArgs(command: string, mcpConfigPath: string | undefined): string[] {
   // Codex and Antigravity have no `--mcp-config` flag; passing it would break launch.
   if (!mcpConfigPath || isCodexCommand(command) || isAntigravityCommand(command)) return [];