Add files, list directories, invoke tools — all without leaving your prompt.

From: x.com/adocomplete

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Introduction

Every second you spend navigating file trees, copying paths, or explaining context to your AI assistant is a second you’re not coding. And those seconds add up fast.

What if I told you there’s a two-character shortcut that eliminates most of that friction? Meet the @ mention — Claude Code’s universal context injection system. It’s deceptively simple: type @, and suddenly you have instant access to files, folders, MCP servers, and subagents.

I’ll be honest: when I first saw @ mentions, I thought "neat feature." After a week of using them, I think they might be overpowered. They’ve fundamentally changed how I interact with Claude, turning what used to be multi-step context-gathering into single, fluid prompts.

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The Problem

Context is everything in AI-assisted development. Claude can write amazing code — but only if it knows what it’s writing code for. The classic workflow looks something like this:

1. You need Claude to modify a file
2. You open the file in your editor
3. You copy the relevant sections
4. You paste them into the chat
5. You explain what file they came from
6. Claude finally has enough context to help

Now multiply that by every file, every function, every piece of documentation you need Claude to understand. It’s exhausting. It breaks your flow. And it makes complex, multi-file tasks feel like herding cats.

The underlying problem? There’s too much friction between "I need Claude to know about this" and "Claude knows about this."

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The Solution

@ mentions collapse that entire workflow into a single gesture. Type @, start typing a filename, and watch as Claude instantly ingests the entire file into its context.

How to Use It

Adding files to context:

@src/components/Button.tsx — can you add hover states to this component?

That’s it. No copying, no pasting, no explaining. Claude now has the full file and can work with it directly.

Adding multiple files:

@src/api/users.ts @src/models/User.ts @tests/users.test.ts

These three files define our user system. The API is returning 500 errors — help me debug.

Listing directories:

@src/components/ — what components do we have for form handling?

Claude will list the directory contents, giving you a quick overview without leaving the conversation.

Invoking MCP servers:

@postgres — run a query to find all users created in the last 24 hours

Enabling subagents:

@researcher — find best practices for implementing rate limiting in Node.js

The beauty is in the consistency. Whether you’re adding files, exploring folders, or invoking tools, the pattern is always the same: @ + name.

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Pro Tips

⌨️ Tab completion is your friend: Type @ and a few characters, then hit Tab. Claude Code will autocomplete file paths, saving you keystrokes and typos.

📁 Glob patterns work: Need all your test files? Try @tests/**/*.test.ts. Claude will add matching files to context.

🔄 Refresh on the fly: If a file changes during your session, just @ mention it again. Claude will reload the latest version.

🎯 Be strategic with context: While @ makes it easy to add files, remember that context has limits. Add what’s relevant, not everything.

💡 Combine with questions: The most powerful pattern is @file + specific question:

@src/utils/cache.ts — is this cache implementation thread-safe?

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Real-World Use Case

Scenario: You’re debugging a complex data pipeline that spans multiple services.

Traditional approach:

1. Open the API controller file, copy relevant code
2. Open the service layer, copy relevant code
3. Open the data model, copy relevant code
4. Open the config file, copy database settings
5. Paste everything into Claude with extensive explanation
6. Realize you forgot the error logs
7. Go get the error logs
8. Finally start debugging

With @ mentions:

I'm seeing data corruption in our pipeline. Here's everything relevant:

@src/api/DataController.ts
@src/services/DataProcessor.ts
@src/models/DataRecord.ts
@config/database.yml
@logs/error.log

The corruption happens after step 3 in the pipeline. What's going wrong?

Time saved: About 5-10 minutes per debugging session. Multiply by dozens of sessions per week, and you’ve reclaimed hours of productive time.

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The Power of Instant Context

What makes @ mentions genuinely game-changing isn’t just the time savings — it’s how they change your thinking. When context injection is frictionless, you start thinking in terms of "what does Claude need to know?" rather than "is it worth the effort to show Claude this?"

That shift leads to better prompts, more comprehensive context, and ultimately better AI assistance. You stop rationing information and start providing Claude with everything it needs to give you the best possible answer.

It’s a small UX improvement that cascades into significantly better outcomes.

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Conclusion

The @ mention might be the highest ROI feature in Claude Code. Two characters that eliminate minutes of friction, repeated hundreds of times per day. It’s not flashy. It’s not complicated. It just works — and it works so well that going back to manual context management feels almost painful.

The fastest path from "I need context" to "Claude has context" is literally just @. Start using it liberally, and watch your AI-assisted development speed transform.

Coming up on Day 18: We’ll explore prompt suggestions — Claude’s ability to predict what you’ll ask next. Because the only thing faster than @ mentions is not having to type at all.

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This article is part of the "31 Days of Claude Code Features" series. Follow along to discover one powerful feature each day.