Septim AI — Vibe-Coding Scaffolds
Build Your AI Tool.
A Next.js starter wired to the Anthropic Claude API with streaming output, a centralized prompt library, and 4 agents for prompt engineering, error handling, cost monitoring, and output validation. Ship your first AI-powered tool in an afternoon.
$99
Pay once · You keep it · No subscription
What's inside
The wiring that takes two days to figure out — already done.
Streaming API calls, prompt centralization, error handling, cost awareness. The starter runs immediately. The agents handle the hard problems that come up when you start building on top of it.
package.json ← Next.js + Anthropic SDK
CLAUDE.md ← project rules for Claude Code
app/
page.tsx ← form + streaming output UI
api/generate/ ← Claude API route, streaming
lib/
anthropic.ts ← client singleton
prompts.ts ← ALL prompts live here
prompt-engineer.md
error-handler.md
cost-monitor.md
output-validator.md
4 agents
The problems that show up after the first demo.
01
Prompt Engineer
Writes, tests, and iterates on system prompts. Produces a draft, test inputs with expected outputs, known failure modes, and the condition that would trigger the next iteration. Treats prompts as code — versioned, tested, documented.
02
Error Handler
Diagnoses and fixes Claude API errors: 401 auth failures, 429 rate limits, streaming cutoffs, and malformed response parsing. Reads the actual error message before suggesting a fix.
03
Cost Monitor
Estimates monthly API cost at your expected usage level and adds per-IP rate limiting to prevent a single script from burning your Anthropic budget before you launch.
04
Output Validator
Adds structured output validation to the API route — checks that Claude's response matches the expected format before it reaches the user, with a one-retry fallback and a user-friendly error on second failure.
Who buys this
The non-developer with an AI idea and Claude Code.
This scaffold is for the person who has an idea for an AI-powered tool — a writing assistant, a scoring tool, a GPT wrapper for a specific industry use case — and is using Claude Code to build it without writing code themselves. The biggest time sinks for this buyer are: figuring out how to get Claude's API response to show up on screen, keeping prompts organized, and understanding why the output is wrong. The scaffold wires the first problem; the four agents handle the other two.
How it works
From idea to live tool in one afternoon.
01 — Buy
Get the scaffold
You'll receive a zip with the starter directory and 4 agent files. Get an Anthropic API key from console.anthropic.com. Add it to a .env.local file. Run npm install && npm run dev — the example tool runs immediately.
02 — Write
Replace the example prompt
Open lib/prompts.ts in Claude Code. Tell the prompt-engineer agent what your tool does and what the output should look like. It writes a tested prompt with failure modes documented. Paste it in.
03 — Ship
Update the UI and deploy
Change the title and placeholder text in app/page.tsx to match your tool. Push to GitHub, connect to Vercel, add your API key as an env var. Live in 90 seconds.
FAQ
Straight answers.
Does this use Claude or GPT?
Claude (Anthropic). The scaffold uses the Anthropic SDK and defaults to claude-3-5-sonnet. The prompt-engineer agent is written to work with Claude's instruction-following behavior. If you want to use OpenAI instead, the scaffold's API route can be rewritten — but the agents won't be calibrated for it.
How much does the Anthropic API cost?
For a new tool with under 100 daily users, typically under $10/month. The cost-monitor agent calculates this precisely for your specific prompt length and usage volume before you launch, so there are no surprises on the bill.
Can I add a paywall to the tool later?
Yes — the SaaS scaffold handles payments. If you start with this scaffold and want to add Stripe + auth later, email Ethan@septimlabs.com. Buyers of both scaffolds get a combined discount.
What's the refund policy?
14-day refund if the scaffold doesn't work for your use case. Email Ethan@septimlabs.com — no form, no hoops.
Ready to build
The API connection is already wired. Your prompt is next.
Streaming output, prompt library, cost monitoring, output validation. Pay once, keep the files.
Pay once · You keep it · No subscription · Ethan@septimlabs.com