PTENES
MODULE 3.2

🧰 Choosing tools and models

The blueprint says what build. Now you choose with what: n8n, Make, or code as the foundation; which LLM for each task; when RAG, MCP, APIs, webhooks, and databases come in. Each choice involves tradeoffs — the goal is to choose based on sound criteria, not trends.

6
Topics
~60
Minutes
Intermediate.
Level
Theory
Type
1

⚖️ n8n vs. Make vs. code

A base that orchestrates your workflow determines your flexibility ceiling and your maintenance floor. There are three paths: n8n (low-code, self-hosted, highly flexible), Make (visual, SaaS, quick to get started) and code (full control, full maintenance).

Make visual · SaaS · fast n8n low-code · self-host Code full control ↑ more control and flexibility · ↓ faster to get started

✓ Start simple when

  • ✓The workflow fits the tool’s built-in connectors.
  • ✓You want to validate the idea quickly, without infrastructure.
  • ✓The logic is straightforward, with no exotic transformations.

✗ Move to code when

  • ✗You hit SaaS execution or licensing limits.
  • ✗A connector is missing, and the glue becomes too fragile.
  • ✗The logic turns into a tangle of nodes that’s impossible to maintain.
Make

Fast, SaaS, visual.

n8n

Flexible, self-hosted.

Code

Maximum control and maintenance.

Migration

The wrong choice costs you later.

2

🧠 When to use an LLM and which model

First: the task needs from an LLM? If a rule, regex, or IF can solve it, use those—they’re cheaper and deterministic. If it requires language interpretation, choose the model based on the cost × capacity: small and inexpensive for classification, large and expensive for complex reasoning.

$

Small / inexpensive model

Classify, extract fields, answer yes/no, label sentiment. Narrow, high-volume tasks where every cent per call matters.

$$

Medium model

Summarize, draft replies, follow multi-step instructions. The default balance for most automations.

$$$

Large / expensive model

Complex reasoning, analysis of long documents, high-stakes decisions. Use it only where the extra capability is worth the cost.

💡 Practical tip

Start with the the cheapest model that works and scale up only if the quality doesn’t meet the metric. The opposite—starting at the top "to be safe"—burns through your budget and hides how much capacity you really need.

Need it?

Can a rule solve this without an LLM?

Cost × cap.

Match the task to the model.

Volume

Cost per token × scale.

Upload

Only if the metric requires it.

3

📚 RAG: your own knowledge in context

The model only knows what it saw during training. When the automation depends on information that only exists in your company — policies, catalog, customer history—you use RAG: retrieves the relevant excerpts from your knowledge base and injects them into the prompt, grounding the AI in your source of truth instead of letting it make things up.

question semantic searchembeddings 📚 your own knowledge base prompt + snippetsinjected context response grounded in your truth illustrative — recover before generating

📐 When RAG Is Worth It (and When It Isn’t)

  • •Applies: your own knowledge, changes frequently, too large to fit in the prompt.
  • •Doesn’t count: the information fits directly in the prompt, or the model already knows it (general knowledge).
  • •RAG adds infrastructure (vector + search) — only take on that cost when it solves a real problem.
Recover

Search before generating.

Embeddings

Search by meaning.

Anchor

Reduces hallucinations.

Only when

There is proprietary knowledge.

4

🔌 MCP and tool integration

When AI needs to act — read a file, query a database, call an API— the MCP (Model Context Protocol) offers a standardized way to connect AI to these tools, without writing different glue code for each one. It's what turns the model from "responds with text" into "uses tools."

🔧 What MCP standardizes

  • •How AI discovers which tools are available and what each one does.
  • •How it invokes a tool and gets the result back.
  • •Reuse: the same MCP server works for any compatible client.

💡 Practical tip

Not every automation needs MCP. If the workflow already orchestrates the steps (n8n determines the order), you can call APIs directly. MCP shines when it’s the AI itself that determines which tool to use and when — that's when standardizing access pays off.

Protocol

Standardized access.

Tools

AI that acts, not just talks.

Reuse

One server, many clients.

When

AI chooses the tool.

5

🔗 APIs, webhooks, and databases

The plumbing of automation. API: you request data when you want it. Webhook: the system notifies you when something happens. Database: you store and look up state between executions. Supabase is a practical example that combines a database + API + authentication in one package.

✓ Use webhook when

  • ✓You want to react as soon as something happens.
  • ✓The event is unpredictable (a client submits a form).
  • ✓Asking “any updates yet?” would be a waste.

✓ Use API/polling when

  • ✓You need to fetch data on demand.
  • ✓The source system doesn't offer a webhook.
  • ✓A fixed check schedule does the job.

🗄️ When you need a database

  • •The automation needs to remember something between executions (state, history).
  • •You need to avoid processing the same item twice (duplicate control).
  • •Supabase provides a Postgres database + REST API + auth with minimal setup.
API

Pull: you request it.

Webhook

Push: it notifies you.

Database

Stores state.

Supabase

Database + API + auth.

6

🎚️ Decision criteria and trade-offs

Every stack choice replaces one thing with another. An explicit set of criteria — cost, delivery speed, maintenance, control, scale, vendor dependence — forces you to justify each decision instead of following trends or habits. And it gives you a good argument in front of the client.

🧾 Trade-Off Matrix (Template)

# rate each option from 1 to 5
criterion | Make | n8n | code
initial cost |  5   |  4  |  3
delivery speed |  5   |  4  |  2
flexibility |  2   |  4  |  5
maintenance (lower=+)|  4   |  4  |  2
scale / limits |  2   |  4  |  5
# weigh what matters in THIS project

⚠️ Attention

Watch out for lock-in: choosing a tool that locks in your data and workflows makes it harder to leave later. And remember that the newest model or the hottest tool is rarely the right choice — simple wins when it's a tie.

No free work

Every choice involves a trade-off.

Criterion

Explicit and weighted.

Lock-in

Think about the cost of leaving.

Simple

Wins in a tie.

🧰 Module Summary

✓
Flow foundation — Make (fast), n8n (flexible), code (full control).
✓
The right model — match the task to cost × capability; not everything needs an LLM.
✓
RAG — only when you have proprietary knowledge to anchor the AI.
✓
MCP and plumbing — APIs (pull), webhooks (push), databases (state), Supabase as a shortcut.
✓
Explicit trade-offs — weighted criteria; when tied, the simpler option wins.

Next Module:

3.3 · Prompt and decision logic design — the brain of the automation.