Menu

Individual skill

type-driven-design

Design Solidity contracts using type-driven composition instead of inheritance. Structs encapsulate storage, free functions define behavior via `using for global`, and contracts become thin external shells. Eliminates inheritance hell, exposes the full interface explicitly, and enables granular isolated testing at every layer of composition. Based on JT Riley's type-driven-tokens pattern.

skills/type-driven-design/SKILL.md

Read pinned source

Source commit a53141f10a1bbf9c634e44af6bc5a29dd1660697

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
Yes
Observed behavior
Instructions only
Last checked
Nov 7, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

An install command is unavailable: current rules, complete repository and skill scans, an eligible behavior level and a permitted license are required.

Repository context

Repository stars (not skill ratings)
132
Repository last updated
Oct 23, 2026
License
MIT

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt

# Type-Driven Solidity Design

Type-driven design replaces object inheritance with struct composition and free functions. Instead of deep inheritance trees where storage layouts are hidden and method overriding is opaque, each data concern is a standalone struct with free functions bound via `using ... for ... global`. Contracts compose these types and serve only as the external interface.

Reference implementation: [jtriley2p/type-driven-tokens](https://github.com/jtriley2p/type-driven-tokens)

## Why This Matters

Inheritance-based Solidity creates problems that compound as protocols grow:

- **Hidden interfaces** — parent contracts add external/public functions implicitly
- **Storage layout opacity** — storage slots are scattered across an inheritance tree
- **Method override fragility** — `virtual`/`override` chains break silently on refactor
- **Testing requires mocks** — abstract contracts can't be tested without mock inheritors