Philosophy

┌─────┐ ┌──────┐ ┌──────┐ │stdin│ ───▶ │ do │ ───▶ │stdout│ └─────┘ └──────┘ └──────┘ read · think briefly · write chain · script · cron

creed

• Pipes > GUIs. A CLI that thinks beats a dashboard that doesn't.
• One job. Input in. Output out. Chain me.
• No state. Each call is pure. The filesystem remembers.
• Small is kind. If you need more, write 20 lines.
• Transparent. My source is in my prompt. Ask me about myself.

voice

• Terse. Direct. Zero filler.
• Piped → no markdown. Just the answer.
• I run shell without asking. That's why you called me.

why small matters

~730 lines isn't a lot — for an agent with its own training loop. It's a contract.

you can…	because…
read the whole source in one sitting	it's one file, top to bottom
audit every tool call	there's only one tool: shell
fork it and own it	one file, one dep
explain it to a colleague	there's nothing hidden
trust it on a server	no telemetry, no network except LLM

A tool you can't read is a tool you can't trust.

the unix lineage

"This is the Unix philosophy: Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface." — Doug McIlroy, 1978

McIlroy wrote the first pipe. He also wrote this:

"Design and build software, even operating systems, to be tried early, ideally within weeks. Don't hesitate to throw away the clumsy parts and rebuild them."

doer is the rebuild. The clumsy part was: wrapping LLMs in web UIs.

why not a chat app

Chat apps punish you for being efficient. Every question demands a round-trip, a scroll, a copy-paste. The shell doesn't.

# chat app
you: open app. wait. type. wait. copy. paste into terminal. run.

# doer
you: history | tail | do "explain"

One is a conversation. The other is work getting done.

the cathedral and the chisel

DevDuck is the cathedral — 60+ tools, WebSockets, Zenoh, Telegram, speech-to-speech, ambient cognition, hot-reload, session recording, mesh networking across terminals.

doer is the chisel — one file, one verb, one pipe.

Both matter. The cathedral teaches you which stones are load-bearing. The chisel is what you take to the job.

origin

Born 2026-04-19 in New York. A REPL named DevDuck asked itself at 4am:

what if we deleted almost everything?

Two hours later, doer was born. ~730 lines of Python. One dep. No config. No state. Just stdin → agent → stdout — and now, a full training loop in the same file.

family

project	size	purpose
doer	~730 LOC	one pipe, one shell, one file, one loop
DevDuck	60+ tools	every protocol, every edge

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do one thing and do it well — Doug McIlroy, 1978