Process calls ctx.task(externalTask)
  → SDK throws EffectRequestedError (journaled)
  → orchestrateIteration returns status="waiting"
  → run:iterate returns nextActions with the effect
  → Orchestrator resolves effect:
     CLI path: resolveAndPostEffect() in orchestration/index.ts
     Internal path: resolveEffect() in orchestration/effects.ts → invokePromptEffect()
  → Result posted back via task:post
  → Next iteration: process resumes with result

// In resolveEffect(), add external agent detection:
if (action.kind === "agent" && action.taskDef?.agent?.external) {
  return resolveExternalAgentEffect(action, args);
}

// packages/genty/platform/src/harness/internal/createRun/orchestration/externalAgentEffect.ts

async function resolveExternalAgentEffect(
  action: EffectAction,
  args: ResolveEffectArgs,
): Promise<EffectResult> {
  const agentDef = action.taskDef?.agent as AgentTaskOptions;
  const adapter = agentDef.adapter;
  const prompt = typeof agentDef.prompt === "string"
    ? agentDef.prompt
    : agentDef.prompt?.instructions?.join("\n") ?? action.taskDef?.title ?? "";

  // Check adapters availability
  const adapterClient = await getAmuxClient();
  if (!adapterClient) {
    if (agentDef.fallbackToInternal) {
      process.stderr.write(`[babysitter] adapters not available, falling back to internal for ${adapter}\n`);
      return resolveInternalAgentEffect(action, args);
    }
    return { status: "error", error: `adapters not available — cannot dispatch to ${adapter}` };
  }

  // Dispatch via adapterBridge (already exists)
  const result = await invokeViaAgentMux(adapterClient, adapter, {
    prompt,
    model: agentDef.model ?? args.model,
    workspace: args.workspace,
    timeout: agentDef.timeout ?? 300_000,
    approvalMode: agentDef.approvalMode ?? "yolo",
    maxTurns: agentDef.maxTurns ?? 10,
    nonInteractive: true,
  });

  // Journal cost event
  if (result.totalCost > 0) {
    await appendEvent({
      runDir: args.runDir,
      eventType: "COST",
      event: {
        source: `external-agent:${adapter}`,
        cost: result.totalCost,
        effectId: action.effectId,
      },
    });
  }

  return {
    status: result.success ? "ok" : "error",
    value: result.output ?? result.lastMessage,
    error: result.success ? undefined : result.lastMessage,
  };
}

if (action.kind === "agent" && action.taskDef?.agent?.external) {
  // Route through adapters instead of internal agent-core session
  const agentDef = action.taskDef.agent;
  const adapter = agentDef.adapter ?? agentDef.name;
  const prompt = typeof agentDef.prompt === "string" ? agentDef.prompt : /* ... */;

  // Use adapters launch CLI
  const launchResult = execFileSync("adapters", [
    "launch", adapter, agentDef.provider ?? "foundry",
    "--model", agentDef.model ?? model ?? "gpt-5.5",
    "--prompt", prompt,
    "--non-interactive",
    "--json",
    "--max-turns", String(agentDef.maxTurns ?? 10),
  ], { cwd: workspace, encoding: "utf8", timeout: agentDef.timeout ?? 300_000 });

  value = JSON.stringify(launchResult);
}