# mycl

> connect your code — a capability/registry system for TypeScript.
> Errors resolve at https://mycl.dev/errors/<code>. Full docs text: https://mycl.dev/llms-full.txt

## Getting Started

- [Introduction](https://mycl.dev/getting-started/introduction/): What mycl is, what it is not, and who reaches for it.
- [Installation](https://mycl.dev/getting-started/installation/): Install mycl in an app or a library, mint your channel, and set up the ./capabilities convention.
- [Quick Start](https://mycl.dev/getting-started/quick-start/): Mint a channel, define a capability, override it per scope, and hand out instances from a factory, all in about a minute.

## Guide

- [Channels](https://mycl.dev/guide/channels/): A channel is a private capability namespace with its own scope context: mint one kernel per app or library, and nothing outside it can see in.
- [Capabilities](https://mycl.dev/guide/capabilities/): A capability is one function that is three things at once, a callable default, a typed contract, and a registry key.
- [Scopes](https://mycl.dev/guide/scopes/): A capability dispatches through the active scope; scope() binds a function to one, and calling a capability with no scope throws loud.
- [Registries & Layers](https://mycl.dev/guide/registries-and-layers/): A registry is an immutable collection of bindings: layer to add them, compose by passing several, and swap I/O in tests without a mock library.
- [Factories](https://mycl.dev/guide/factories/): mycl(make, ...registries) returns a frozen factory: registries resolve once at creation, the builder runs per call and its result comes back verbatim.
- [Augmentation](https://mycl.dev/guide/augmentation/): .augment(cap, wrapper) composes around whatever a capability resolves to, so you can observe, transform, or recover from it without replacing the implementation.
- [Layer Strategies](https://mycl.dev/guide/layer-strategies/): Attach a LayerStrategy to a capability: a left fold over its layers (accumulate a list, concatenate strings) instead of the default last-binding-wins.
- [Snapshots & Async](https://mycl.dev/guide/snapshots-and-async/): A scope lives on the synchronous stack, so async callbacks escape it, and snapshot(fn) pins the active scope into a function you can call later while, on Node, alsContext does it automatically.

## Advanced

- [The Core Substrate](https://mycl.dev/advanced/core-substrate/): Why @mycl/core splits into a main entry (the everyday kernel) and substrate subpaths (/helpers, /context, /factory, /introspect), and how to read a registry at runtime.
- [Building a Kernel](https://mycl.dev/advanced/building-a-kernel/): Write a connector (a fresh context plus a kernel builder), stand a channel up with createChannel(name, connector), and swap the context later with setChannelContext (AsyncLocalStorage).
- [Type Guarantees](https://mycl.dev/advanced/type-guarantees/): How mycl's types enforce contracts at the layer boundary: the Capability discriminant, AnyCapability, requires provider-completeness, and reading a registry's type-level layers.
- [Duplicate Detection](https://mycl.dev/advanced/duplicate-detection/): Why duplicate copies coexist harmlessly by construction, the one real hazard (cross-copy token mixing), the duplicate-identifier guard (error 13), and a self-report recipe for libraries that want startup detection.
- [Prior Art](https://mycl.dev/advanced/concepts/): The established ideas mycl draws on (effects and handlers, the expression problem, microkernels, information hiding, and aspects), each mapped to the part of mycl it informs.

## Reference

- [@mycl/core](https://mycl.dev/reference/core/): Complete API reference for @mycl/core, covering every exported function and type across its five entry points, with signatures, error codes, and minimal examples.
- [Glossary](https://mycl.dev/reference/glossary/): Every mycl term, defined once.
- [Changelog](https://mycl.dev/reference/changelog/): Release history for @mycl/core, one section per published version.

## For Agents

- [Using mycl (for agents)](https://mycl.dev/agents/using-mycl/): Terse operating manual for AI agents reading, writing, and extending mycl code, covering invariants, conventions, recipes, and a drop-in AGENTS.md block.