← Back to blog

Understanding the Agentic Loop in Codex and Claude Code

2026-03-06

AI coding tools are evolving fast. What started as autocomplete and chat-based assistants is turning into something much more powerful: autonomous coding agents.

Tools like OpenAI Codex and Claude Code don’t just generate snippets anymore. They can plan tasks, modify files, run commands, and iterate until a problem is solved.

At the core of these systems is a concept called the agentic loop.

Understanding this loop explains how modern AI coding agents actually work.


What Is an Agentic Loop?

An agentic loop is the core workflow that allows an AI agent to repeatedly reason, act, and evaluate until a task is complete.

Instead of responding once to a prompt, the agent enters a loop where it:

  1. Understands the task
  2. Plans the steps
  3. Executes actions (tools, code edits, commands)
  4. Evaluates the result
  5. Adjusts the plan

This cycle repeats until the task is solved.

In tools like Claude Code, the loop typically looks like:

This loop allows AI agents to behave more like engineers working on a problem, not just chatbots answering questions.


The Agentic Loop in Claude Code

Claude Code is a terminal-native coding agent designed to work directly with your codebase.

Instead of only generating code in chat, it can:

  • Read repository files
  • Edit multiple files
  • run shell commands
  • install dependencies
  • run tests

Claude Code follows an agentic loop that typically works like this:

1. Understand the Request

Example prompt:

“Add authentication to this Next.js app.”

Claude gathers context from:

  • the repository structure
  • relevant files
  • configuration files
  • dependencies

This step is critical because coding agents rely heavily on context gathering before planning changes.


2. Generate a Plan

The agent decomposes the task into subtasks such as:

  • Add login page
  • Install auth library
  • Implement API routes
  • Protect private routes
  • Update UI

This transforms a single prompt into a structured engineering plan.


3. Execute Actions

Next, the agent begins acting on the environment.

Actions may include:

  • editing files
  • creating new modules
  • running shell commands
  • installing packages
  • executing tests

Claude Code can output combinations of files, shell commands, and explanations while executing tasks.


4. Evaluate the Result

After executing steps, the agent evaluates whether the change worked.

It might:

  • run the build
  • run tests
  • inspect errors
  • read logs

If something fails, the agent loops back to planning.


5. Iterate Until Completion

The loop repeats until the system determines the task is complete.

Finally, the agent summarizes the changes and presents them to the developer.

This iterative process allows the agent to self-correct and refine its work.


The Agentic Loop in Codex

OpenAI’s Codex uses a similar architecture.

At its core is a state-machine style agent loop that coordinates:

  • the user
  • the language model
  • external tools and commands

This loop orchestrates interactions between the model and the development environment.

Codex can:

  • navigate file systems
  • run commands
  • write code
  • execute tasks in isolated environments

The loop continues until the agent reaches a valid solution.


Why the Agentic Loop Matters

The agentic loop is what transforms AI from a coding assistant into a coding agent.

Traditional AI tools work like this:

Agentic systems work like this:

This difference enables AI systems to solve much more complex engineering tasks.


From Copilots to Autonomous Developers

Agentic loops are the foundation of a new development paradigm.

Instead of AI simply helping developers write code, agents can now:

  • implement features
  • refactor codebases
  • fix bugs
  • run tests
  • prepare pull requests

Research and industry adoption show that coding agents like Codex and Claude are becoming active participants in software development workflows, not just assistants.


The Future of Agentic Development

The rise of agentic loops signals a major shift in how software will be built.

Developers may increasingly focus on:

  • defining goals
  • designing architecture
  • supervising AI agents
  • reviewing results

Meanwhile, AI agents handle the repetitive implementation work.

In other words, the role of engineers evolves from writing every line of code to orchestrating intelligent systems that build software with them.


The most powerful AI coding tools aren’t the ones that generate code fastest.
They’re the ones that can keep working until the problem is solved.