Command vs. Sub-agent in Claude Code: A Guide on When to Use Each
Hey everyone, if you've been diving into the world of AI-powered development, you've probably come across Claude Code. It's a pretty incredible tool from Anthropic that's changing the way a lot of us write, debug, & ship code. It’s like having a coding partner right in your terminal, ready to jump in & help with everything from refactoring a tricky function to writing documentation.
But as you get more comfortable with Claude Code, you'll start to notice there are a couple of different ways to get things done: using commands & using sub-agents. At first, they might seem a little similar, but it turns out they're designed for VERY different things. Honestly, figuring out when to use a command versus when to spin up a sub-agent is one of those "aha!" moments that can seriously level up your workflow.
So, I wanted to break it all down. Think of this as your friendly guide to understanding the core differences, the specific use cases for each, & how to combine them to create a seriously efficient & powerful development process. Let's get into it.
First Off, What Exactly Are Commands in Claude Code?
Alright, let's start with the basics. Commands in Claude Code are essentially direct instructions you give to the AI. They are the most straightforward way to interact with the tool & are perfect for those "in the moment" tasks where you want to maintain a high degree of control. Think of it as a "human in the loop" approach. You're telling Claude exactly what to do, & it does it.
You've probably already used some of the built-in slash commands. If you type
in your terminal within a Claude Code session, you'll see a list of them. These are your go-to tools for a lot of common development tasks:
- : To run your test suite.
- : To execute a specific script or command.
- : To make changes to a file.
- : To commit changes to your git repository.
- : To clear the current context & start fresh.
These are just a few examples, but they all share a common trait: they are immediate & task-oriented. You have a specific thing you want to do, you issue the command, & Claude gets to work.
Beyond the built-in commands, you can also create your own custom slash commands. This is a super powerful feature that a lot of people overlook. You can create a markdown file in your
directory, & just like that, you have a custom, reusable prompt. For example, you could create a
command that scaffolds out a new React component with your preferred file structure & boilerplate. It's a fantastic way to automate those small, repetitive tasks that eat up your day.
So, When Should You Be Using Commands?
This is the million-dollar question, right? Here’s my take on it, based on my own experience & what I’ve seen in the community. Commands are your best friend in a few key scenarios:
1. For Quick, One-Off Tasks: This is the most common use case. Need to quickly refactor a single function? Use the
command. Want to run your linter on a specific file?
is your go-to. Commands are perfect for these kinds of "one & done" operations where you don't need a lot of complex, multi-step logic.
2. When You Need to Be Highly Interactive: Debugging is a perfect example of this. When you're trying to squash a bug, you're often in a back-&-forth process of inspecting code, running tests, & making small changes. Commands are ideal for this because they allow you to stay in control every step of the way. You can ask Claude to read a file, then run a test, then suggest a fix, all as separate, discrete steps.
3. When You Want to Maintain Full Control: Sometimes, you don't want the AI to go off & do its own thing. You want to be the one calling the shots. With commands, you're the pilot. Claude is your very capable co-pilot, but you're the one giving the orders. This is especially important when you're working on critical parts of your codebase or when you're just not ready to hand over the reins completely.
4. For Simple, Repetitive Prompts: As I mentioned earlier, custom slash commands are a game-changer for this. If you find yourself typing the same prompt over & over again, turn it into a command! It's a simple way to streamline your workflow without the overhead of creating a full-blown sub-agent.
Now, Let's Talk About Sub-Agents: Your Specialized AI Team
Okay, so if commands are for direct, human-in-the-loop tasks, what are sub-agents for? Well, if commands make you the pilot, sub-agents are like hiring a team of specialists. A sub-agent is essentially a pre-configured, specialized instance of Claude Code that you can delegate complex tasks to.
Here's what makes sub-agents so powerful:
- They Have Their Own Context: This is HUGE. Each sub-agent operates in its own isolated context window. This means it can focus on a specific task without getting "polluted" by the main conversation. You can have a sub-agent working on a complex feature in the background while you continue to work on other things in your main chat.
- They Have Custom System Prompts: You can give each sub-agent a detailed system prompt that defines its role, its personality, & its specific instructions. For example, you could create a "senior_developer" sub-agent that's an expert in your specific tech stack, or a "code_reviewer" sub-agent that's a stickler for your team's coding standards.
- They Have Their Own Tool Permissions: You can decide exactly which tools each sub-agent is allowed to use. This is great for security & for ensuring that sub-agents don't accidentally do something they're not supposed to. For example, you might give your "database_manager" sub-agent access to your database tools, but not your "documentation_writer" sub-agent.
Creating a sub-agent is surprisingly easy. You can use the
command in Claude Code to create & manage them. You'll give it a name, a detailed prompt, & a list of tools it can use.
When Should You Reach for a Sub-Agent?
Sub-agents really shine when you're dealing with more complex, multi-step, or repeatable workflows. Here are some of the best times to use them:
1. For Complex, Multi-Step Tasks: Imagine you need to add a new feature to your application. This might involve creating new files, writing code, adding tests, & updating documentation. This is a perfect job for a sub-agent. You can create a "feature_implementer" sub-agent, give it a detailed plan, & let it go to work. It will handle all the individual steps, keeping track of its progress along the way.
2. For Repeatable, Standardized Workflows: Do you have a standard process for releasing new code? Maybe it involves running a series of tests, creating a new git tag, & deploying to a staging environment. You can create a "release_manager" sub-agent to handle this entire process for you. This ensures that your releases are consistent & that no steps get missed.
3. For Delegating Specialized Work: This is where sub-agents REALLY start to feel like having a team of AI developers. You can create sub-agents for all sorts of specialized tasks:
- A "Code Reviewer" that checks for common errors, style guide violations, & potential bugs.
- A "Test Writer" that can look at your code & generate a comprehensive suite of tests.
- A "Documentation Writer" that can generate user-friendly documentation for your new features.
- A "Refactoring Expert" that can analyze your codebase & suggest improvements for performance & readability.
The possibilities are pretty much endless here. If you can define a role & a set of tasks, you can probably create a sub-agent for it.
4. When You Want to Scale Your Efforts: As your projects get bigger & more complex, a single AI assistant can start to struggle. Sub-agents allow you to scale your development efforts by delegating tasks to specialized workers. This keeps your main conversation focused on high-level strategy, while the sub-agents handle the nitty-gritty implementation details.
A Quick Detour: AI for Customer-Facing Interactions
It’s pretty cool to think about how we can build these specialized AI assistants for our own development workflows. And it gets you thinking about where else this kind of technology can be applied. For a lot of businesses, the next logical step is to use this same concept of specialized AI to interact with customers.
This is where a platform like Arsturn comes in. While Claude Code is all about our internal development, Arsturn helps businesses build their own custom AI chatbots for their websites. These aren't your old-school, clunky chatbots that can only answer a few pre-programmed questions. With Arsturn, you can create a no-code AI chatbot that's trained on your own business data.
This means it can provide instant, personalized customer support, answer detailed questions about your products or services, & even help with lead generation, 24/7. It’s a lot like creating a sub-agent for your customer service team. You give it a specific role, train it on the right information, & let it go to work engaging with your website visitors. It's a great example of how this kind of conversational AI is being used to build meaningful connections with an audience.
Head-to-Head: Command vs. Sub-Agent
So, to wrap my head around it, I find it helpful to just put them side-by-side. Here’s a quick breakdown of the key differences:
| Feature | Commands | Sub-Agents |
|---|
| Primary Use Case | Quick, one-off, interactive tasks | Complex, multi-step, repeatable workflows |
| Control | High (Human-in-the-loop) | Delegated (AI takes the lead) |
| Context | Shared with the main conversation | Separate, isolated context window |
| Configuration | Simple, direct instructions | Highly customizable with system prompts & tools |
| Example | to make a quick change | A "test_runner" sub-agent to run tests, diagnose failures, & suggest fixes |
Creating a Powerful Workflow with Both
Here's the thing: it's not really a matter of "command OR sub-agent." The real magic happens when you start using them together. You can use commands for your day-to-day, moment-to-moment tasks, & then call on your sub-agents when you need to delegate something more complex.
For example, you might be working on a new feature & use commands to explore the codebase & make some initial changes. Then, when you're ready to write the tests, you could invoke your "test_writer" sub-agent by saying something like, "Hey, use the test_writer sub-agent to create some new tests for the feature I just built."
This kind of hybrid approach gives you the best of both worlds: the fine-grained control of commands & the powerful delegation capabilities of sub-agents.
Wrapping It Up
So, there you have it. A hopefully not-too-complicated breakdown of commands & sub-agents in Claude Code. The key takeaway is this: commands are for when you want to be in the driver's seat, & sub-agents are for when you want to hire a specialist.
Honestly, the best way to really get a feel for this is to just jump in & start experimenting. Create a few custom commands for your most common tasks. Try building a simple sub-agent to handle a part of your workflow that you find tedious. You'll be surprised at how quickly it starts to click & how much more efficient your coding sessions become.
Hope this was helpful! I'd love to hear how you all are using commands & sub-agents in your own projects. Let me know what you think.