Monitoring Agents

use std.fs
use std.log

type PayError = Declined | Denied(reason: String)

capability Payments {
    fn refund(order: Int, amount: Int) ! PayError
}

type Bank: Payments {
    fn refund(self, order: Int, amount: Int) ! PayError {
    }
}

type RefundIssued: LogEvent {
    order: Int
    amount: Int
}

type RefundBlocked: LogEvent {
    order: Int
    reason: String
}

agent Refunder {
    settings AgentSettings(audit: Audit())
    can Payments.refund

    limit Payments.refund {
        amount <= 500
    }

    on refund(order: Int, amount: Int) ! PayError {
        Payments.refund(order, amount) catch e => {
            log.warn(RefundBlocked(order: order, reason: "{e}"))
            fail e
        }
        log.info(RefundIssued(order: order, amount: amount))
    }
}

fn main() ! Error {
    const bot = Refunder.start(Payments: Bank())
    bot.refund(1, 400) catch _ => {}
    bot.refund(2, 900) catch _ => {}
    print("-- the audit log --")
    for line in try fs.lines("agents/Refunder/audit.log") {
        print(line.split("Z ").last() ?? line)
    }
}

[log]
level = "info"
file = "logs/agents.log"      # also kept on disk, a new file every 10 MB

[log.otlp]
endpoint = "http://localhost:4318"   # OTLP over HTTP
service = "refunds"

use std.fs

type Verdict {
    /// true if the customer is unhappy
    complaint: Bool
}

type PayError = Declined | Denied(reason: String)

capability Payments {
    fn refund(order: Int, amount: Int) ! PayError
}

type Bank: Payments {
    fn refund(self, order: Int, amount: Int) ! PayError {
        print("refunded {amount} on order {order}")
    }
}

agent Support {
    model Model(name: "claude-haiku-5-5", thinking: false)
    settings AgentSettings(audit: Audit(format: AuditFormat.JsonLines))
    can Ai, Payments.refund

    limit Payments.refund {
        amount <= 500
    }

    on handle(order: Int, amount: Int, note: String) ! Error {
        const v = try ask<Verdict>("Is this a complaint? {note}")
        if v.complaint {
            try Payments.refund(order, amount)
        }
    }
}

fn main() ! Error {
    const bot = Support.start(Payments: Bank())
    try bot.handle(7, 40, "My order never came.")
    bot.handle(8, 900, "It broke on day one.") catch e => print("refused: {e}")
    for line in try fs.lines("agents/Support/audit.log") {
        // The time changes every run, so it is cut out here.
        print("{line.slice(0, 9)}…{line.slice(29, line.len())}")
    }
}

settings AgentSettings(audit: Audit(otlp: true))

[log.otlp]
endpoint = "http://localhost:4318"

agent Support {
    settings AgentSettings(audit: Audit(otlp: true))
    can Console

    on note(text: String) {
        print(text)
    }
}

fn main() {
    Support.start().note("never runs")
}