A Claude agent is Claude working autonomously toward a goal — thinking, using tools, and taking multiple steps on its own, instead of just answering a single prompt. You can use ready-made agents like Claude Code, or build your own with the Claude Agent SDK and tool use. This beginner’s guide explains how.
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Key Takeaways
- What it is: an agent uses tools and loops through steps to complete a goal, not just reply once.
- Three ways to use them: Claude Code (ready-made), build your own (Agent SDK + API), or Managed Agents (Anthropic-hosted).
- How it works: think → use a tool → read the result → repeat until done.
- You’ll need: an API key, some tools for Claude to call, and a loop (the SDK can run it for you).
- Golden rule: add guardrails and human review — agents act, so mistakes have consequences.
What is a Claude agent?
A normal API call is one question and one answer. An agent is different — it works toward a goal over many steps.
Give it a task, and Claude decides what to do: which tool to call, what to check next, and when it’s finished.
The key idea is autonomy. The agent chooses its own path rather than following a fixed script.
Claude Code is a great example — you ask for a feature, and it explores, edits and tests on its own. See our Claude Code guide for that ready-made version.

How does a Claude agent work?
Under the hood, an agent runs a simple loop:
- Think — Claude reasons about the goal and decides the next step.
- Act — it calls a tool (search a database, run code, call an API).
- Observe — the tool’s result is fed back to Claude.
- Repeat — it continues until the task is done.
That loop is what turns a chatbot into a worker. Each cycle, Claude gets closer to finishing the job.
You define the tools; Claude decides when and how to use them.
Three ways to use Claude agents
You don’t always have to build from scratch. There are three main paths:
- Use a ready-made agent — like Claude Code for software work.
- Build your own — with the Claude Agent SDK and tool use, running the loop yourself.
- Use Managed Agents — where Anthropic hosts and runs the agent for you.
Pick based on how much control you need and how much you want to manage.
Option 1: Claude Code (a ready-made agent)
The easiest way to experience a Claude agent is Claude Code.
It’s a fully built coding agent that reads your codebase, edits files, runs commands and commits to git — no development required on your part.
If your goal is software work, start here before building anything custom. It’s included with a Claude Pro plan.

Option 2: Build your own agent with the Claude Agent SDK
For custom agents, you use the Claude Agent SDK (or the API directly) plus tool use.
First, you define tools — small functions Claude can call, each with a name, a description and its inputs.
Then you run the agent loop. The SDK’s tool runner can drive it for you: it calls Claude, runs the tool Claude picks, feeds the result back, and repeats until Claude is done.
Here’s the shape of it in Python:
from anthropic import Anthropic
client = Anthropic()
tools = [{
"name": "get_weather",
"description": "Get the current weather for a city.",
"input_schema": {
"type": "object",
"properties": {"city": {"type": "string"}},
"required": ["city"],
},
}]
# The agent loop: call Claude, run any tool it requests, send the
# result back, and repeat until it stops asking for tools.
response = client.messages.create(
model="claude-sonnet-4-6",
max_tokens=1024,
tools=tools,
messages=[{"role": "user", "content": "What's the weather in Dhaka?"}],
)When Claude wants a tool, your code runs it and returns the result; the loop continues. To build with the API, see our Claude API guide.
Option 3: Managed Agents (Anthropic-hosted)
If you’d rather not run the loop and infrastructure yourself, Managed Agents does it for you.
You create an agent configuration once — its model, instructions, tools and skills. Anthropic stores it.
Then you start a session for each task. Anthropic runs the agent loop and provides a secure workspace where its tools execute.
This suits long-running, stateful agents where you want the hosting handled for you.
What are tools, MCP and skills?
Three building blocks make Claude agents powerful.
Tools are functions Claude can call — the hands of the agent. Without tools, it can only talk; with them, it can act.
MCP (Model Context Protocol) is an open standard for connecting agents to your data and services — databases, issue trackers, internal systems — through one common interface.
Skills package task-specific know-how the agent loads only when relevant, so it can specialise without bloating every prompt.
When should you build a Claude agent?
Agents are powerful, but not always the right tool. Build one only when the task justifies it.
A good checklist before you commit:
- Complexity — is the task multi-step and hard to script in advance?
- Value — does the result justify higher cost and slower runs?
- Viability — is Claude actually good at this kind of task?
- Cost of error — can mistakes be caught and undone (tests, review, rollback)?
If any answer is “no,” a simpler single call or a fixed workflow is usually better.

What can Claude agents do? Real examples
Agents shine when a task needs several steps and some judgement. Common examples:
- Coding agent — build a feature, fix bugs, run tests (that’s Claude Code).
- Research agent — search sources, read them, and write a summary.
- Data agent — pull data, clean it, and produce a report.
- Support agent — answer questions and take actions in your systems.
- Ops agent — monitor something and respond when a condition is met.
If a job would take a person several steps and a few tools, it’s a candidate for an agent.
How much do Claude agents cost to run?
An agent’s cost depends on how many steps it takes. Each step is an API call, and each call uses tokens.
A simple three-step agent is cheap. A long, autonomous agent that loops many times uses far more tokens — so cost scales with autonomy.
To keep costs sane, use a cheaper model for routine steps, cap the number of steps, and trim context. Our Claude pricing guide and models comparison have the details.
Claude agents vs a simple workflow
Not every task needs an agent. If the steps are always the same, a fixed workflow is cheaper, faster and more predictable.
Use a plain API call for one-shot tasks like summarising or classifying.
Reach for an agent only when the path can’t be fully planned in advance and Claude needs to decide as it goes.
Common mistakes when building agents
- Too many tools. A bloated tool list confuses the model — keep it focused.
- No step or spend limits. A runaway loop can burn tokens fast.
- Wrong model. Using a huge model for simple steps wastes money.
- No human review. Letting an agent take risky actions unchecked is dangerous.
- Over-engineering. Building an agent when a single API call would do.
Best practices for Claude agents
Because agents take actions, safety habits matter more than with a plain chatbot.
- Keep a human in the loop for risky or irreversible actions.
- Limit the tools to what the task needs — fewer tools, less can go wrong.
- Guard destructive actions — require confirmation before deleting or sending.
- Set limits on steps and spend so a runaway loop can’t rack up costs.
- Log everything so you can see what the agent did and why.
- Pick the right model — capable models for hard reasoning, cheaper ones for simple steps.
Where do you run a Claude agent?
If you build your own agent, it needs somewhere to run — a server that hosts your code and calls the Claude API.
For most projects, an affordable VPS like Hostinger is enough to get started.
For agents that scale or run continuously, managed cloud hosting such as Cloudways makes life easier.
With Managed Agents, Anthropic hosts the workspace, so you don’t manage that part yourself.
Disclosure: some links in this article are affiliate links. If you buy through them we may earn a commission at no extra cost to you. We only recommend tools we’d use ourselves.

Managed vs self-hosted: which should you choose?
Both are valid — it depends on how much control you want.
Self-hosted (you run the loop and infrastructure) gives maximum flexibility and keeps compute on your side.
Managed Agents hands the loop, hosting and tool sandbox to Anthropic, so you ship faster with less to maintain.
A simple rule: start managed to move quickly, and self-host when you need custom control or your own compute.
Frequently Asked Questions
What is a Claude agent?
A Claude agent is Claude working autonomously toward a goal — using tools and taking multiple steps on its own, instead of answering a single prompt. Claude Code is a ready-made example; you can also build custom agents with the Claude Agent SDK.
How do I build a Claude agent?
Define tools (functions Claude can call), then run the agent loop: call Claude, execute any tool it requests, feed the result back, and repeat until it’s done. The Claude Agent SDK’s tool runner can handle that loop for you. You’ll need an API key to start.
What is the difference between Claude Code and a custom agent?
Claude Code is a ready-made agent built for software tasks — no development needed. A custom agent is one you build yourself with the Agent SDK and your own tools, for any task you choose. Start with Claude Code if your work is coding.
What are Managed Agents?
Managed Agents are Claude agents that Anthropic hosts and runs for you. You define the agent once, then start a session per task; Anthropic runs the loop and provides a secure workspace where the agent’s tools execute. It suits long-running, stateful agents.
Do I need to be a developer to use Claude agents?
To use Claude Code, only lightly — you talk to it in plain English. To build custom agents with the Agent SDK, yes, you need some coding ability, since you define tools and handle results. Beginners should start with Claude Code.
The bottom line
Claude agents turn the assistant from something that answers into something that acts. The fastest way in is Claude Code; the most flexible is building your own with the Agent SDK; the easiest to host is Managed Agents.
Whichever you pick, start small, add guardrails, and keep a human in the loop. For the wider toolset, read our complete Claude AI guide.











