Jan 10, 2026
Claude Code has been shipping at a blistering pace. But buried in the recent 2.1.x releases is a fundamental shift in how the tool thinks about extensibility. The changes to skills, slash commands, and subagents might look incremental, but they’re pointing toward something bigger: these three abstractions are merging into one.
Let me explain what’s happening and where I think this is headed.
The Three Abstractions (And Why They Exist)
Claude Code currently has three different ways to extend its capabilities. Each came about at different times, solving different problems.
Slash Commands are the simplest. You have a prompt you use often. Instead of typing it every time, you save it to a file and invoke it with /command-name. That’s it. A saved prompt with a shortcut.
Skills evolved from slash commands. The key difference: a skill isn’t just a markdown file—it’s a folder. That folder contains your prompt (skill.md) plus supporting resources: code snippets, HTML templates, whatever the skill needs. This lets you build capabilities that go beyond text, like parsing PDFs or generating Word documents.
Subagents do two things. First, they let you define a persona: “You are an expert code reviewer. Here’s how you do reviews.” Second—and this is the important part—they run in their own context window. They don’t fill up your main conversation.
Here’s how invocation used to work:
- Slash commands: Explicit. You type
/commandand it runs. - Skills: Auto-discovered. The model sees your intent, checks its skills folder, and pulls in relevant ones. Only the name and description load initially—the full skill loads on-demand.
- Subagents: Run in their own context window, spawned when needed.
But reading the above you can probably already see the cracks appearing. Even though each abstraction had a good reason to exist at the time it was introduced, now that you have all three it makes choosing one not entirely straightforward. If you want to give the model a new capability there is a fair bit of head-scratching involved. Which abstraction best fits what I want to do? They all overlap with each other to some extent.
What Changed
The recent releases blur all these lines.
Skills can be invoked as slash commands. Skills now appear in the / menu. You can explicitly invoke them. They still auto-discover, but explicit invocation is now an option. The physical difference in how skills and commands were invoked is now gone.
Skills can run in their own context. A new front matter field, context: fork, lets a skill run as a subagent—in its own context window. This was subagents’ whole reason for existing.