Claude Cowork for Beginners: Build Your Own Jarvis

TL;DR

Build a personal AI assistant using Claude's file-reading system with markdown instruction files, persistent memory, and layered workstations to automate tasks like emails, finances, and projects.

Key Points

• 1.The entire system runs on two simple text files. A `claude.md` instruction file and a `memory.md` notepad file form the root of the workspace — no coding required, just plain text rules Claude reads at session start.
• 2.The architecture mirrors a constitutional hierarchy. Root `claude.md` acts like a constitution applying to all tasks; individual workstations (Email HQ, Personal Finances) have their own `claude.md` files whose rules stack on top, similar to state laws layering under federal law.
• 3.Persistent memory is enabled by two simple rules. Claude reads `memory.md` before every session and writes to it whenever told to 'remember this,' giving it continuity across separate conversations without any external database.
• 4.A voice principles file makes Claude write in your style. Claude analyzes your last 30 sent Gmail emails (or 5 pasted writing samples) to extract tone patterns — the creator's own file exceeded 150 lines of extracted preferences.
• 5.Universal workstations (e.g. Email HQ) vs. dedicated workstations (e.g. Personal Finances) serve different scopes. Email HQ layers email-specific rules like greetings and inbox-zero workflows on top of root voice principles; Personal Finances built a master spending tracker spreadsheet from 12 months of credit card statements.
• 6.Three tactics keep token usage and costs low. Keep root `claude.md` under 300 lines, never repeat the same rule across multiple files, and default to Sonnet model (1/5th the cost of Opus) — only switching to Opus for tasks with three or more interdependent steps.
• 7.A '/session audit' skill captures unsaved preferences automatically. Running it at session end triggers Claude to scan the conversation for any principles or preferences not yet saved to memory, ensuring nothing is lost between sessions.