Framework

STACK

STACK is a five-layer architecture for repositories where humans and agents share work: Structure, Toolchain, Agent configuration, Connection, Knowledge and quality. The agent OS is versioned like the app.

When to use it

Use STACK when agents demo well and then rot the repo: rules in five tools, MCP without contracts, skills nobody owns. The disease is agentic repo debt, not a weak model.

The moves

  1. 1

    Structure

    Layout, entry points, workspaces, and boundaries an agent can navigate on its first minute in the repo.

  2. 2

    Toolchain

    The shells, commands, and CLI contracts an agent is allowed to run, written down instead of remembered.

  3. 3

    Agent configuration

    AGENTS.md, CLAUDE.md, rules, skills, and subagent charters as versioned standing context.

  4. 4

    Connection

    MCP servers, tool contracts, hooks, and guardrails with least privilege and a real failure story.

  5. 5

    Knowledge and quality

    Memory tiers, context budgets, evals, and CI, so a model upgrade does not silently lower the bar.

The book

Available now

The Agentic Codebase

The Five-Layer Architecture That Makes Agent Work Survive Production
The article The series

Related frameworks

CHORUS

The Multi-Agent Organization

CHORUS is a six-skill coordination protocol for teams of 2 to 15 people who share work with specialised AI workers: Charter, Handoff, Orchestrate, Review, Update, Sync. Org charts name reporting lines. CHORUS names coordination lines.

 SENSE

AI Agents for Startup Strategy

SENSE is a five-move strategic intelligence layer: Scan, Evaluate, Navigate, Simulate, Execute. It turns agent work from a productivity shortcut into a sourced claim that changes a watchlist, an assumption register, or a Monday decision.

 BooksOS

The Agentic Author

BooksOS is a gated production system for serious nonfiction: Brief, Bible, Map, Draft, Edit, Package, Launch. Agents do specialist work inside the gates. Judgment, voice, and accountability stay human.

STACK is the five-layer model in The Agentic Codebase. It is not a generic "AI stack" diagram and not a vendor product line.

Citation

STACK (The Agentic Codebase). Len P. van der Hof, Systems for the Strategic Self. https://lenvanderhof.com/frameworks/stack/