A note from Sebastian

Kostya — this is the upgrade.

You already build beautiful things in the Claude app. This page is the case for the next floor: running Claude — and Codex — straight from your terminal, where it stops being a chat window and starts being a machine that does the work. Read it top to bottom, then paste the prompt at the end into a fresh session and let it study your setup for you.

Why I dragged you into this

The chat window is a demo. The CLI is the workshop.

Last night I did a garbage job explaining this, so here's the clean version. In the desktop app you describe an app and Claude builds you something gorgeous — you've been doing exactly that, and it shows. But every one of those apps lives in a sandbox you have to copy things out of. You're the courier between the AI and your real files, your real projects, your real business.

The command-line version deletes the courier. It runs in your actual folders. It edits real files, runs real commands, spins up background agents, and connects the apps you already built to each other through code. Same Claude brain — but now it has hands, and the hands are in your workshop instead of behind glass.

The one-line pitch

Desktop Claude answers you. CLI Claude works for you. Once you're past the first hour, you stop asking it for code and start handing it jobs.

Read this first

“Is it safe to let this thing into my computer?”

Fair question — and the honest answer is: only if you set it up so it can't surprise you. Here's exactly how the trust works, so you're never handing over blind control.

It asks before it acts

Out of the box, the CLI requests permission before it runs a command, edits a file, or touches anything outside the current folder. You approve each kind of action once. Nothing happens silently. You can also run it in a read-only / “plan” mode where it looks and proposes but changes nothing until you say go.

You start it where you want it

It only sees the folder you launch it in. Open it inside one project directory and that project is its whole world — it can't wander into the rest of your machine unless you point it there.

The real risk: a poisoned installer

The one thing worth being paranoid about isn't the tool — it's fake copies of the tool. So verify what you're installing. Two rules make it safe:

  • Only install from the official domainsclaude.ai / code.claude.com for Claude Code, chatgpt.com / openai.com for Codex. Not a random GitHub mirror, not a link someone DMs you.
  • Verify the signature. Anthropic signs every release with a GPG key. You can confirm the download is genuinely theirs and untampered before you trust it. Steps are in the install section below — do them once and you're certain.

Bottom line: the CLI is more auditable than the app, not less — you can see every command it wants to run and veto it. The skepticism is correct; it just points at the installer, not the tool.

Pick your fighter — or both

Install the CLIs

You liked the idea of flipping to another Warp tab and working in Codex — so here's both. Run Claude Code in one tab, Codex in another, and you've got two AI coworkers side by side. Every command below is copied verbatim from the official docs (verified 2026-07-23).

Claude Code (Anthropic) — my daily driver

# official native installer — macOS / Linux
curl -fsSL https://claude.ai/install.sh | bash

Prefer Homebrew? brew install --cask claude-code. Prefer npm (needs Node 22+)? npm install -g @anthropic-ai/claude-code. Then start it by running claude inside any project folder. Needs a Claude Pro/Max account to sign in.

Codex (OpenAI) — the other tab

# official — via npm
npm install -g @openai/codex

# or Homebrew
brew install --cask codex

# or standalone installer
curl -fsSL https://chatgpt.com/codex/install.sh | sh

Start it with codex, then choose Sign in with ChatGPT. Same move as Claude — launch it inside the folder you want it to work in.

The verify-it's-genuine step (do once)

This is the safety check from above, made concrete. It confirms Anthropic really signed the release you downloaded:

# import Anthropic's public signing key + show its fingerprint
curl -fsSL https://downloads.claude.ai/keys/claude-code.asc | gpg --import
gpg --fingerprint security@anthropic.com

# the fingerprint MUST read exactly:
# 31DD DE24 DDFA B679 F42D  7BD2 BAA9 29FF 1A7E CACE

If that fingerprint matches, the key is authentic — and anything it verifies is genuinely Anthropic's. (Full binary-checksum steps live in the official setup docs.)

Watch it once

Your first five minutes

This is the whole on-ramp — open Warp, and step through it. Nothing here changes a file without your yes.

Notice the shape: it explains, it asks, then it acts. That “Allow?” prompt is the safety model from earlier, live.

The map — what to actually look into

Four things that make it a machine

These are the four capabilities that took me from “nice code helper” to “this runs part of my business.” Open each one. The prompt at the bottom of this page will go research all of them against your own setup — but skim them first so you know what you're aiming at.

01Skills & slash commands

What it is: reusable instructions you save once and fire with a /name. I've got dozens — /morning, /save, one that drafts client emails in my exact voice. The /caveman one I mentioned just makes Claude answer in compressed shorthand so you spend fewer tokens per task.

Why you'd care: every repetitive thing you do — a show recap, a booking confirmation, prepping a gig sheet — becomes one word.

# try this inside Claude Code:
Create a skill called /gig-sheet that turns a booking
email into a one-page run sheet: date, venue, load-in
time, audience, tech notes, and my set list.
02The Agent SDK — connect the apps you already build

What it is: the headline. The SDK lets you put Claude inside the apps you build — so instead of a pretty front-end that just sits there, the app itself can reason, draft, decide, and act. The same engine that runs the CLI, callable from your own code.

Why you'd care: that gorgeous booking app you built? Wire the SDK in and it can read an inquiry, draft the reply in your voice, and slot the date — instead of you doing it by hand behind the nice UI.

# try this — point it at something you built:
Take one app I've already built. Show me the smallest
change that uses the Claude Agent SDK to make it act on
its own data instead of just displaying it.
03MCP servers — give it your tools

What it is: a standard way to plug Claude into your stuff — your calendar, a database, Slack, a payment system, a Google Drive. Once connected, it can read and act on that thing directly, no copy-paste.

Why you'd care: “What shows do I have this month, and draft confirmation texts for the two that haven't paid deposits.” It pulls the calendar, checks the payments, writes the texts — because those tools are wired in.

# try this:
What MCP servers exist for the tools I use — calendar,
email, database, Slack? Show me how to connect one, and
explain exactly what it can and can't touch.
04Hooks, cron & subagents — it runs without you

What it is: automation. Hooks fire on events (something happens → Claude does a thing). Cron / scheduled agents run on a clock (every morning at 6, do X). Subagents let it split a big job across several workers in parallel.

Why you'd care: a 6am agent that reads overnight booking inquiries and drafts replies to your inbox before you're awake. You review, you send. The business moves while you sleep.

# try this:
Give me one realistic morning scheduled-agent for my
business — does something useful with my real data and
leaves the result for me to approve, sends nothing itself.
Straight talk

Desktop app vs. the CLI

I'm not going to pretend the app is bad — it's where you'll still prototype UIs. But as a daily driver, this is the honest comparison:

What each one is actually for.
Desktop app The CLI
Where it works Its own sandbox — you copy results out Your real folders & files, in place
Can it run commands? Limited, inside the sandbox Yes — with your per-action approval
Connect your tools A few, curated Anything, via MCP
Automate / schedule No Yes — hooks, cron, agents
Build it into your apps No Yes — the Agent SDK
Two AIs at once One window Claude in one tab, Codex in the next
Best at Fast UI prototypes, casual chat Doing the actual work, repeatedly
The whole point of this page

Now let it study your setup

Here's the payoff. Open a fresh Claude Code session inside your main projects folder and paste this. It researches everything above, then looks at your actual machine — safely, read-only, asking before anything — and hands you a personal report of where the CLI and SDK would save you the most time. It ends by offering to build one small starter so you learn by running something real.

Paste this into a fresh Claude Code session  ·  your CLI launchpad
You are my onboarding guide to Claude Code and the Claude Agent
SDK. I'm brand new to the CLI but I build apps in the Claude
desktop app and I run a live-magic / mentalism business. Work in
phases and DO NOT change, create, or delete any file, and DO NOT
run any command that modifies anything, without stopping to
explain it and getting my explicit yes first. Start read-only.

PHASE 1 — RESEARCH (no file access needed): In plain language,
teach me the four capabilities that make the CLI more than a chat
window: (1) Skills & slash commands, (2) the Claude Agent SDK,
(3) MCP servers, (4) hooks / scheduled agents / subagents. For
each: what it is, one concrete example for a magic-performance
business, and where the official docs are.

PHASE 2 — DISCOVER MY SETUP (read-only): With my permission for
each step, look through this folder and my projects to figure out
what I actually have — languages, frameworks, the apps I've built,
databases, calendars, services. Don't open anything sensitive
without asking. Summarize my stack back so I can confirm it.

PHASE 3 — ANALYZE: Give me a prioritized list of where moving to
the CLI + Agent SDK would help me most. For each: what it is,
which capability it uses, rough effort, and the concrete payoff
for my business. Be honest about where the desktop app still wins.

PHASE 4 — BUILD A STARTER (only after I pick one): Let me choose
one item. Scaffold the smallest working version — a simple skill
or a small MCP/SDK hookup — explaining each step, asking before
you create or run anything, so I understand what we built.

Throughout: explain like I'm sharp but new to this, keep the
safety rails visible, never take an action I haven't approved.

The copy button grabs the full prompt (it's a bit longer than what's shown). Paste, hit enter, and go make coffee.

One more thing I showed you

Run your own private AI at home

Remember the “Spark boxes” I mentioned setting up at the office? That's the other half of this. A Spark box is just a dedicated, always-on machine running an AI model locally — your own private ChatGPT that never phones home. I reach mine from anywhere over a private mesh. You can build the exact same thing, and for a mentalist it's genuinely valuable: your client data, your booking info, and — the big one — your methods and routine ideas never leave your house or land in some vendor's logs.

Where local wins vs. where the cloud still wins
Keep both. Use each for what it's good at.
Your local box wins Cloud (Claude / GPT) still wins
Privacy — methods & client data never leave home Peak quality — best reasoning & writing
Free & unlimited after the hardware Huge context — whole books at once
Works offline — green room, plane, venue The hardest coding & agent work
An always-on assistant over your own files Zero maintenance — nothing to run

The one thing not to buy

There's an NVIDIA product literally called the “DGX Spark.” Don't reflexively buy it just because it shares the name with my boxes — mine is just a nickname for the setup, not that hardware. The DGX Spark is real (~$4,699) but it's genuinely slow for the back-and-forth chat you'd actually do (it's built for a different job). If you're on a Mac, you already own the better path.

Your hardware options, honestly

Memory size decides how big a model fits; memory speed decides how fast it talks.
Path Cost Good for
A Mac you already own (16 GB+) $0 Start here this weekend — runs solid 8–14B models
Mac Mini M4 Pro, 64 GB ~$2,000 The real always-on “Spark box.” Quiet, sips power, runs 30B models easily + a big 70B. My pick for you.
Gaming PC w/ RTX 5090 (32 GB) ~$3–4k Fastest per-word, but loud/hot — only if you want a PC
NVIDIA DGX Spark ~$4,699 Skip for chat — it's a fine-tuning dev kit, not this

Do it this weekend — free, on the Mac you have

This is the whole pattern — a private model with a real API — in about fifteen minutes and zero dollars. Each command is safe and reversible.

# 1. install Ollama (the easiest local-AI runner)
brew install ollama

# 2. pull a great small model. On 32GB+ RAM, try qwen3:32b instead
ollama pull qwen3:8b

# 3. chat with it — fully private, offline-capable
ollama run qwen3:8b

# 4. prove it's a real API your own apps can call
curl http://localhost:11434/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{"model":"qwen3:8b","messages":[{"role":"user","content":"Say hi"}]}'

Want to reach it from your laptop at a gig? Install Tailscale on the home Mac and your laptop, sign into both with the same account, and they join one private network — no router settings, nothing exposed to the internet. That's the “from anywhere” part of my setup, and it's another fifteen minutes.

Where it earns its keep for you

Or just let your CLI set it up with you

Same idea as the big prompt above — paste this into Claude Code and it walks you through the whole thing, asking before every step:

I want to run a private local LLM on this Mac — my own
always-on AI that keeps my data at home. I'm new to this and
cautious about what gets installed, so explain each step and
ask before installing or running anything. Walk me through:
checking this Mac's memory and which model fits, installing
Ollama and pulling the right model, confirming it works + how
to call its local API from my apps, and optionally Tailscale
so I can reach it from my laptop at a gig without exposing
anything. Then suggest a few ways a mentalist could use it.