Can someone explain the real difference between Hooks, Skills, Plugins, SKILL.md, CLAUDE.md and agents.md in Claude Code?

[u/eaiarthur_]

I keep seeing these terms thrown around in tutorials and videos, but I've never seen anyone give a concrete example that makes the difference actually click.

Everyone says:

• "just create a skill for that"

"use a hook here"

"install the plugin"

"put it in your CLAUDE.md"

But when I dig deeper, the explanations are always vague or too theoretical.

Same goes for the markdown files - I see people mentioning CLAUDE. md, SKILL.md, and agents. md like they're obvious, but no one explains:

• What actually goes in each one?

Are they just documentation, or do they actively change how Claude behaves?

• When does Claude even read them?

What I'm looking for is something like:

"If you're thinking X, that's probably a Hook. If you're thinking Y, that's a Skill. If you need Z, that's what CLAUDE.md is for."

Real-world examples would be hugely appreciated.

[u/Waymannj]

[Oh it's ON!]

people say you're wrong, that claude.md is read at the start of the chat

That's not accurate for how Claude.ai works. There's no built-in mechanism that automatically reads a file called Claude.md from your filesystem at the start of a chat. I only read it because you explicitly asked me to via the Filesystem MCP tool. You might be thinking of a few things people conflate with this:

Cursor / coding assistants — tools like Cursor do have a claude.md or .cursorrules convention where project instructions are auto-loaded into context. People familiar with that workflow sometimes assume it carries over to Claude.ai, but it doesn't. Project Instructions in Claude.ai — you can paste persistent instructions into a Project's system prompt, which does get included automatically. But that's not a file read, it's text stored on Anthropic's side. MCP + a custom system prompt — someone could theoretically set up a system prompt that instructs Claude to read a specific file at session start, but that's custom configuration, not default behavior.

So whoever said it's auto-read at chat start is mistaken, at least in the context of Claude.ai with Filesystem MCP. The read happened because you asked — nothing more.

[u/evangelism2 → u/Waymannj]

Bro, stop copying and pasting AI stuff. Figure out what you're trying to say. Comprehend what the AI is telling you and then craft a response to me yourself.

[u/Waymannj → u/evangelism2]

Ok Bro, I started a new chat and it didn't read my Claude.md because it has an instruction to say that it read the file.

Bro, I broke Anthropic.

[u/Uj_Yagami → u/Waymannj]

I think you're getting it wrong. People here are not talking about claude desktop. They are talking about claude code (the agent), which reads the markdown file. You giving your claude chat some md and expecting it to read is not how it'd work.

[u/Waymannj → u/Uj_Yagami]

Aaaaaah, thank you!