Field Notes
Production notes on AI agents, DeFi safety, and hardening your systems — each one carved from a real guide, not filler.
Every AI agent — including the coding agents you use daily — runs the same four-step loop. Here it is in 40 lines of runnable Python, with the design decisions that keep it from melting down.
Your agent forgets everything when the program exits. Here's the memory ladder: in-context history, a JSON file that persists between runs, and a save_memory tool so the agent decides what's worth keeping.
Phishing, malicious approvals, seed theft, rug pulls, fake airdrops — the five attacks that actually drain DeFi wallets, and the checklist that blocks every one.
Your DNS queries travel in plain text — readable by your ISP and anyone on the network. Encrypt them with DNS-over-TLS on Ubuntu using systemd-resolved, in five minutes.
A default SSH install accepts passwords — and the internet never stops guessing them. Three moves make it near-impenetrable: Ed25519 keys, a hardened sshd_config, and fail2ban.
Every on-chain transaction is public — if you know how to read it. How to decode a transaction on Etherscan and run the five-step contract check before you interact with any DeFi protocol.