Claude Code adds Mods plugin system for JavaScript and TypeScript extensions

On October 3, 2026, The Decoder reported that Anthropic has introduced a system called Mods for Claude Code, its command-line coding tool. According to the article, Mods is essentially middleware that runs directly inside the tool, giving developers a way to rewrite parts of it from the inside rather than bolting features on from outside.

The report says developers write their extensions in JavaScript or TypeScript. With those scripts, they can reshape both the interface and the behavior of Claude Code: adding custom panels, intercepting tool calls as they happen, or wiring up new commands the tool did not previously have. In The Decoder's framing, the point is that customization reaches past configuration files into how the tool operates while it is running.

The report does not give a version number for the Mods system, a release date, or a list of who can use it. It says nothing about pricing or supported platforms, and it does not indicate whether the feature is available to all Claude Code users or only a subset. No statement from Anthropic itself appears in the material, and no other outlet's coverage is included, so The Decoder's article is the only account that can be checked against.

That leaves the announcement at a fairly early and narrow stage as far as the available material goes: a middleware layer for Claude Code, written in JavaScript or TypeScript, that can add panels, intercept tool calls, and register new commands. How far that reaches in practice, and when developers outside the initial group will see it, is not something the material addresses.