Comprehensive guide9 min read

What is agentic coding?

SFEIR Institute•

TL;DR

Agentic coding is an approach where an autonomous AI agent reads, modifies, and tests your code from natural language instructions. Claude Code, the CLI tool from Anthropic, embodies this method by orchestrating complete tasks directly from your terminal, from refactoring to deployment.

Agentic coding is an approach where an autonomous AI agent reads, modifies, and tests your code from natural language instructions. Claude Code, the tool from Anthropic, embodies this method by orchestrating complete tasks from refactoring to deployment. It is editor-agnostic and runs across the terminal, IDE extensions (VS Code, JetBrains), a desktop app, and the web.

Agentic coding is a software development paradigm where an artificial intelligence agent performs programming tasks autonomously, by reading existing code, proposing modifications, and applying them without manual intervention. Claude Code stands out as the leading tool for this approach, with a rapidly growing developer community.

This comprehensive guide explains concretely what agentic coding is, how it works, and why it is redefining development practices. Check out the main Claude Code hub for an overview of the ecosystem.

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How is agentic coding transforming software development?

Agentic coding marks a breakthrough in the way code is produced. Instead of writing each line, you describe the intent to an agent that orchestrates the entire execution.

A coding agent is a program that combines a language model (LLM) with system tools: file reading, command execution, and Git repository navigation. It operates in an autonomous loop until the stated objective is achieved.

In practice, you formulate a request like "add email validation to the sign-up form" and the agent:

  1. Analyzes the project tree structure
  2. Identifies the relevant files
  3. Writes the validation code
  4. Runs the existing tests
  5. Fixes any detected errors automatically

according to user feedback, agentic coding significantly reduces the time spent on refactoring tasks. This autonomy is what sets the agentic approach apart from simple autocompletion.

For a deeper look at the internal mechanics, see the in-depth analysis of agentic coding which details each component of the agentic loop.

Key takeaway: agentic coding delegates execution to an autonomous agent. You shift from being a code writer to an intent architect.

Why move from hand-written code to orchestrated code?

Traditional development relies on a write, compile, test, fix cycle. Agentic coding compresses these steps into a single AI-driven loop.

Code orchestration is the ability of an agent to chain actions (read, modify, execute, validate) without human intervention between each step. You describe the expected result and the agent determines the path.

The table below illustrates the typical differences in approach (the values are indicative, not measured benchmarks):

CriterionHand-written codeCode orchestrated by an agent
Refactoring effortManual, file by fileDelegated to the agent
Files modified simultaneouslyA handful at a timeMany across the project
Error detectionAfter compilationDuring the agentic loop
Project contextDeveloper's memoryAutomatic analysis

In practice, the agent can rapidly scan a large codebase to understand its structure, far faster than reading it by hand.

Moving to orchestrated code does not eliminate technical expertise. You still need to understand the architecture, validate the agent's choices, and evaluate the quality of the produced code. The agentic coding FAQ answers common questions on this topic.

Key takeaway: orchestrating code means steering an agent by intent rather than by syntax, without giving up technical control.

How does Claude Code work as an agent in your terminal?

Claude Code is an agentic development tool developed by Anthropic. It is editor-agnostic and runs across the terminal, IDE extensions (VS Code, Cursor, JetBrains), a desktop app, and the web, with settings, CLAUDE.md, and MCP servers shared across every surface.

Install Claude Code with npm in a single command:

npm install -g @anthropic-ai/claude-code

Launch the agent in your project directory:

cd my-project
claude

The tool automatically reads and indexes your codebase, and works with any programming language your project uses. For a detailed procedure, follow the installation and first launch guide.

Here is how a typical session works:

$ claude "Add unit tests for the auth module"
# Claude Code analyzes the module, identifies untested
# functions, generates test files, runs Jest
# and fixes failed assertions

Claude Code has a CLAUDE.md memory system that persists your preferences and project conventions between sessions. This file stores architecture rules and specific constraints.

The permissions and security system gives you fine-grained control over allowed actions: read-only, command execution, or full autonomous mode.

SFEIR Institute offers a one-day Claude Code training where you practice installation, configuration, and agentic workflows in hands-on labs. You leave with a working environment and the reflexes needed to pilot the agent daily.

Key takeaway: Claude Code is a CLI agent that reads, modifies, and tests your code from the terminal, with a built-in memory and permissions system.

What are the advantages of Claude Code over Copilot and Cursor?

The fundamental distinction lies in the level of autonomy. GitHub Copilot is an autocompletion assistant integrated into the editor. Cursor is a fork of VS Code embedding an AI agent in the graphical interface.

Claude Code is an editor-agnostic agent that orchestrates multi-file tasks. It runs in the terminal, in IDE extensions (VS Code, Cursor, JetBrains), in a desktop app, and on the web, executing shell commands, navigating Git, and modifying dozens of files in a single request.

FeatureClaude CodeGitHub CopilotCursor
Interaction modeTerminal, IDE, desktop, webEditor extensionFull editor
AutonomyFull agentAutocompletion + chatAgent in IDE
Multi-file editingYes, nativeLimitedYes
Command executionYes (bash, git, npm)NoLimited
Context windowUp to 1M tokensVaries by modelVaries by model
Monthly price (pro)See official pricingSee vendor pricingSee vendor pricing

According to industry surveys, the majority of developers use at least one AI assistance tool, but only a minority leverage an autonomous agent. Find a detailed analysis in the full tool comparison.

In practice, Claude Code excels at refactoring tasks involving more than 10 files simultaneously. Use Copilot for quick autocompletion and Claude Code for structured task orchestration.

Key takeaway: Claude Code differentiates itself through full terminal autonomy and its ability to orchestrate modifications across an entire project.

How to choose between Haiku, Sonnet, and Opus?

Anthropic offers three models for Claude Code, each suited to a different usage profile. The choice of model influences the speed, accuracy, and cost of each request.

Haiku is the fastest and least expensive model in the Claude lineup, designed for short tasks. Sonnet is the mid-range model offering a balance between performance and cost. Opus is the most powerful model, intended for complex analyses.

CharacteristicClaude Haiku 4.5Claude Sonnet 4.6Claude Opus 4.8
Response speedFastestFastModerate
Context window200K tokens1M tokens1M tokens
Input cost (1M tokens)Lowest, see official pricingMid, see official pricingHighest, see official pricing
Output cost (1M tokens)Lowest, see official pricingMid, see official pricingHighest, see official pricing
Optimal use caseShort scripts, triageDaily developmentRefactoring, audit

Configure the default model in your session:

claude --model opus "Refactor the payment module"
claude --model haiku "Generate a SQL migration script"

In practice, Haiku responds noticeably faster than Opus on simple requests. Choose Haiku for quick, repetitive tasks, Sonnet for everyday development, and Opus for deep architectural analyses.

The context management guide explains how to optimize token consumption regardless of the model. Also discover the essential slash commands for piloting each model.

Key takeaway: Haiku for speed, Sonnet for daily balance, Opus for maximum power. Match the model to the complexity of the task.

How much do Claude Code pricing plans cost?

Claude Code requires an Anthropic subscription or an API key. Several access modes are available.

A token is a unit of text of approximately 4 characters in English. Each interaction consumes tokens as input (your request + context) and as output (the agent's response).

Anthropic offers several access modes:

  • Claude Pro: basic access with a token quota
  • Claude Max: intensive use with higher quotas, no per-token billing
  • Claude Team / Enterprise: for organizations
  • Direct API key: pay-per-use via the Anthropic API

For current plan prices, see the official pricing.

PlanToken billingRecommended usage
Claude ProQuota includedOccasional use
Claude Max 5xHigh quota, no per-token costDaily development
Claude Max 20xVery high quota, no per-token costIntensive use
API keyPay-per-useCI/CD, automation

In practice, an average refactoring session consumes between 50,000 and 200,000 tokens. With a Max plan, you do not need to worry about per-token costs.

Check your consumption in real time with the /cost command inside a Claude Code session.

Most professional Claude Code users opt for a Max plan. The beginner's guide to agentic coding details each option step by step. Also consult the glossary to master the vocabulary related to billing.

Key takeaway: Claude Code requires an Anthropic subscription (Pro, Max, Team, or Enterprise) or an API key. The Max plan is recommended for daily professional use.

What concrete use cases justify agentic coding?

Agentic coding applies to scenarios where automating multi-file tasks generates a measurable time savings. Large-scale refactoring is the systematic rewriting of existing code to improve its structure without changing its behavior.

Explore the detailed use cases for complete examples with metrics.

Main use cases:

  1. Multi-file refactoring: rename a function used in 40 files with a single command
  2. Test generation: create unit tests for an uncovered module
  3. Framework migration: convert React class components to functional components
  4. Security audit: scan a project to detect vulnerable dependencies
  5. Documentation: generate API documentation from source code
  6. Code review: analyze a pull request and suggest improvements

Concrete refactoring example:

$ claude "Convert all callbacks to async/await in src/"
# The agent identifies 23 files containing callbacks,
# converts them, runs the tests, and displays the result

according to user feedback, teams using coding agents report a notable reduction in their review cycle. Agentic coding adoption is growing rapidly among development teams.

SFEIR Institute supports this transition with the AI-Augmented Developer 2-day training. You practice piloting AI agents on real projects, with labs covering refactoring, test generation, and CI/CD integration. To go further, the AI-Augmented Developer - Advanced one-day training deepens multi-agent orchestration techniques and advanced prompt engineering.

Key takeaway: agentic coding covers refactoring, tests, migrations, and audits: any scenario involving systematic modifications across a project.

How to get started with agentic coding in practice?

Start by installing the prerequisites: Node.js 18 or higher and an Anthropic account with an API key. The native installer (curl/irm) needs no Node.js at all. Installation takes less than 2 minutes.

Quick start steps:

  1. Install Node.js 18 or higher from nodejs.org
  2. Run npm install -g @anthropic-ai/claude-code
  3. Configure your API key: export ANTHROPIC_API_KEY=sk-...
  4. Open a terminal in your project
  5. Launch claude and ask your first question

For complete instructions, follow the Your first conversations with Claude Code guide that walks you step by step through your first interactions with the agent.

Create a CLAUDE.md file at the root of your project to store your conventions:

# Project conventions
- Framework: Next.js 15
- Style: TypeScript strict
- Tests: Vitest
- Commits: conventional commits in English

In practice, even a short CLAUDE.md file is enough to noticeably reduce repeated manual corrections on the agent's responses. Regularly check that your conventions stay up to date.

Agentic coding does not replace your expertise. It amplifies your productivity by automating repetitive tasks. You retain control over the architecture, technical choices, and final validation.

Key takeaway: get started in 2 minutes with Node.js 18 or higher, an API key, and a CLAUDE.md file. Agentic coding is learned through practice.


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