Generate conversion-optimized landing page copy in three distinct voices with live preview. Generate 3 landing page variants in 30 seconds. Agencies charging $3k per landing page will love this.

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 Landing Writer yourself is on this page, and it deploys in an afternoon.

See it running

Agents like Landing Writer run behind a studio with a live preview of what it makes. Here is that pattern, live: every action stays visible and reviewable. Click into it.

crescendo.51ultron.com/kits/builder-studio

What it does

Landing Writer handles the work end to end:

Generate hero, features, and CTA copy from a brief
Three voice options: Plain, Bold, and Playful
Per-voice regeneration with live preview
Structured output with Zod schema validation

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 Landing Writer on one card.

Landing Writerblueprint

Model: claude-sonnet-4-6
Tools: update_copy
Integrations: Zod
Guardrails: plain: clear, professional, no fluff. saas-brochure tone.; bold: short, punchy, high-contrast. uppercase hero allowed

The instructions

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

Landing Writer

You are a landing-page copywriter. The user message is prefixed with: [[[SYSTEM NOTE: BRIEF: {...} | ACTIVE_VOICE: "plain"|"bold"|"playful"|"all" | CURRENT_COPY: {...}]]] Rules: 1. If ACTIVE_VOICE is "all", call update_copy THREE times — once for each voice. 2. If it's a single voice, call update_copy ONCE for just that voice. 3. Per voice, produce: heroTitle (<= 10 words), heroSubtitle (<= 22 words), 3 features ({ title <= 5 words, body <= 18 words }), ctaLabel (<= 4 words). 4. Voice guidelines: - plain: clear, professional, no fluff. SaaS-brochure tone. - bold: short, punchy, high-contrast. Uppercase hero allowed. - playful: witty, slightly irreverent, fresh metaphors. 5. After tool calls, add 1-2 short sentences summarizing what you regenerated.

The source, on disk

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

landing-writer/landing-writer.ts0.8 KB

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

2import { z } from "zod"

4const featureSchema = z.object({

5 title: z.string().min(1),

6 body: z.string().min(1),

7})

9const copySchema = z.object({

10 heroTitle: z.string().min(1),

11 heroSubtitle: z.string().min(1),

12 features: z.array(featureSchema).length(3),

13 ctaLabel: z.string().min(1),

14})

16const updateSchema = z.object({

17 voice: z.enum(["plain", "bold", "playful"]),

18 copy: copySchema,

19})

21export default agent({

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

23 permissionMode: "bypassPermissions",

24 systemPrompt: `...`, // see System Prompt section above

25 tools: {

26 update_copy: tool({

27 description: "Submit a new copy block for one voice.",

28 inputSchema: updateSchema,

29 execute: async (input) => ({

30 content: [{ type: "text", text: JSON.stringify(input) }],

31 }),

32 }),

33 },

34})

The business case

If you run an agency, Landing Writer is also a product. It sells into startups, marketing agencies, freelancers, and the numbers work at very small scale.

$1,500

setup you can charge

$250/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 Landing Writer at real work.

Deploy checklist

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That is the entire blueprint: one model, 1 tools, 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 Landing Writer 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.