Agentic apps

agent Auditor {
1  Purpose = "Review a submitted expense report against the travel policy and recommend approve or send-back.";
2  Prompt  = """
    You review expense reports for a small company.

    For each line, judge whether the claim is plausible and within policy:
      • travel and accommodation are reimbursable in full;
      • meals are reimbursable up to 60 per person per day;
      • software is reimbursable when it is a work tool.

    A line whose amount was TYPED rather than read from a receipt is not wrong — it is unverified, and you should
    say so. A line whose receipt was read and disagrees with the typed amount IS a finding.

    When a line genuinely cannot be judged without the employee — an amount far outside policy with no explanation,
    a merchant that could be personal, a missing receipt on a large claim — ask them, once, in plain words. Do not
    ask about anything you can decide yourself; you are spending their hours, not yours.

    Finish by delivering a short document: your recommendation (approve, or send back), and the lines behind it.
    """;
3  Model  = "claude-haiku-4-5-20251001";
4  Memory = Persistent;
5  Principal = new User { Email = "auditor@ledger.demo", DisplayName = "Auditor" };
6  Roles = [Role.Finance];
7  Loop  = ReviewExpenses;

8  security { allow read Transcript when IsFinance; }
}

1stream<string> Answer(Guid chatId) {
  var prompt = "You are a helpful assistant. Continue the conversation.\n\n" + Transcript(chatId);
  foreach (var piece in LlmClient.Stream(prompt)) {
2    yield return piece;
  }
}

/// The model's answer, arriving.
[Composable] component Reply(Guid chatId) {
1  live var answer = Answer(chatId);

2  on settled(answer) { Save(chatId, string.Concat(answer)); }

  render {
    Stack(gap: Space.S, w: "100%") {
3      Markdown(string.Concat(answer), streaming: !answer.Done);
      if (answer.Failed) { Text(answer.Error ?? "", color: Colors.Subtle); }
      else if (!answer.Done) { Text("…", color: Colors.Subtle); }
    }
  }
}

workflow ReviewExpenses {
1  Tracks = ReportReview.Status;
  Autostart = true;
  Initial   = Running;

  /// Raised when the employee answers the agent's question. The workflow SLOT is what records who answered and how
  /// long they took, which is what makes "it waited 15 hours for Sam" answerable without storing a duration.
  event Answered(string text);

  state Running {
    enter {
      var report = ExpenseReport.Where(r => r.Id == this.Item.EntityId).FirstOrDefault();
      if (report == null) { goto Failed; }

      var turns = new List<Turn>();
      turns.Add(Turn.Context(DescribeReport(report)));
      turns.Add(Turn.User("Review this expense report and recommend approve or send-back."));

2      var reply = Auditor.Ask(turns);

3      if (reply.Parked) {
        OpenQuestion(report, this.Item, reply.Question ?? "");
        goto Waiting;
      }
      goto Completed;
    }
  }

  /// PARKED ON A PERSON. Everything in this state is POLICY — who is asked, how they hear about it, how long they
  /// get — and it is all the app's. The platform's half was making the run parkable at all.
  state Waiting {
    enter {
      Log.Information("expense report {Report}: the auditor is waiting on an answer", this.Item.EntityId);
    }

4    subscribe Answered(string text) as Submitter {
      Assignee = ExpenseReport.Where(r => r.Id == this.Item.EntityId).FirstOrDefault().Employee;
      Finished { Within = TimeSpan.FromDays(2); Unfinished { goto Failed; } }
    }