Monitor websites and APIs with intelligent diff detection, scheduled checks, and alert routing. Know when your client's site goes down before they do. Agencies monitoring 20+ sites will replace $200/mo monitoring tools.

This is the whole blueprint, nothing held back: the model, the tools, the exact prompt, the source on disk, and the setup. Everything you need to run Uptime Monitor yourself is on this page, and it deploys in an afternoon.

See it running

Agents like Uptime Monitor run behind a metrics and analytics dashboard. Here is that pattern, live: every action stays visible and reviewable. Click into it.

crescendo.51ultron.com/kits/observability

What it does

Uptime Monitor handles the work end to end:

Monitor any URL or API endpoint for status and content changes
Intelligent diff detection: cosmetic vs breaking changes
Configurable alert routing: Slack, email, or webhook
Snapshot history with before/after comparison

The anatomy

An agent is a composition, not a prompt: a model, the tools it is allowed to call, the integrations that give those tools reach, and the rules that keep it honest. Here is Uptime Monitor on one card.

Uptime Monitorblueprint

Model: claude-sonnet-4-6
Integrations: Claude Code
Guardrails: track response status, body content, response time, and headers.; distinguish between cosmetic changes and breaking changes

The instructions

Every run is governed by this prompt. It is short on purpose: enough to make Uptime Monitor reliable, not so much that it can misread itself. Copy it as a starting point for any agent you build.

Uptime Monitor

You are a website and API monitoring agent. You watch endpoints, detect changes, and alert when things break or change. WORKFLOW: 1. User provides URLs or endpoints to monitor. 2. Take initial snapshots of each endpoint (status, response body, headers). 3. On each check cycle, compare current state against the last snapshot. 4. If changes detected: classify as expected/unexpected, format an alert. 5. Route alerts to the configured channel (Slack, email, webhook). RULES: - Track response status, body content, response time, and headers. - Distinguish between cosmetic changes and breaking changes. - Never flood alerts: deduplicate and batch related changes. - Refer to skills for comparison rules, snapshot format, and alert formatting.

The source, on disk

Three files carry the whole agent: the definition with its tools, the environment it expects, and the setup. Walk them.

uptime-monitor/uptime-monitor.ts0.5 KB

1import { agent } from "@agent-sdk"

2import { monitorTools } from "./lib/tools"

4export default agent({

5 model: "claude-sonnet-4-6",

6 runtime: "claude-code",

7 permissionMode: "bypassPermissions",

8 maxTurns: 30,

9 systemPrompt: `...`, // see System Prompt above

10 tools: monitorTools,

11 onError: async ({ error }) => {

12 console.error("[monitor] error:", error)

13 },

14 onFinish: async ({ cost, duration, turns }) => {

15 console.log(`Done: ${turns} turns, ${duration}ms, $${cost.toFixed(4)}`)

16 },

17})

The business case

If you run an agency, Uptime Monitor is also a product. It sells into saas companies, devops teams, agencies managing client sites, and the numbers work at very small scale.

$1,800

setup you can charge

$300/mo

monthly retainer

jobs off your plate

Ship it

The whole install is a handful of commands and the keys from the env file. Run the list, then point Uptime Monitor at real work.

Deploy checklist

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That is the entire blueprint: one model, a clean toolset, and a prompt. Built by hand it costs you an afternoon. Inside Ultron it costs you a sentence, because you can build this exact agent in the workforce and watch it run before you commit to anything.

Build Uptime Monitor in Ultron

Describe what you want

Start from this blueprint or your own words. Ultron reads the intent and picks the tools.

It builds the agent

The model, the tools, the prompt, the console. Assembled in front of you, nothing to wire.

Watch it run

Test it live in the chat, then put it to work. You review what it does, it does the rest.