How to Use Claude Code and Codex Together on One Project

February 2026 • 7 min read

The AI coding landscape has evolved past the point of choosing a single agent. Claude Code excels at complex reasoning, multi-file refactors, and deep architecture work. OpenAI's Codex CLI is fast, focused, and excellent for targeted edits and code generation. The smartest developers in 2026 are not picking one or the other -- they are using both on the same project.

The problem? Running two AI coding agents on a single codebase turns your terminal into a mess of overlapping sessions, lost context, and constant re-explanation. This guide shows you how to set up a clean dual-agent workflow using Beam, so Claude Code and Codex work together instead of against each other.

Why Use Both Agents?

Claude Code and Codex CLI have fundamentally different strengths. Claude Code, built by Anthropic, is one of the most capable reasoning engines available for software development. It can hold an entire codebase in its head, trace complex dependency chains, and plan multi-step refactors that touch dozens of files. When you need to redesign an authentication module, migrate a database schema, or debug a race condition buried three layers deep, Claude Code is the tool you reach for.

Codex CLI, from OpenAI, takes a different approach. It is fast, direct, and excels at focused execution. Need to update every test file to match a new interface? Generate boilerplate for a new API endpoint? Write documentation for twenty functions? Codex handles targeted, repetitive tasks with speed that makes it the perfect complement to Claude Code's deep reasoning.

The real power emerges when you combine them. Consider a practical example: Claude Code spends twenty minutes redesigning your API schema, restructuring the route handlers, updating the middleware, and documenting the architectural decisions. Then Codex takes over, quickly updating all 40 test files to match the new schema, generating the OpenAPI spec, and adding type definitions across the client codebase. What would take one agent an hour takes both agents half that time, each working in its area of strength.

The Problem: Scattered Terminals, No Shared Context

In theory, using two agents sounds straightforward. In practice, it creates immediate organizational problems. Two AI agents means at least two active terminal sessions. But you also need terminals for your dev server, your test runner, git operations, log watching, and database management. Before you know it, you have eight or more terminal windows scattered across your screen with no clear structure.

Standard terminal applications offer no native way to group these sessions by purpose. Your Claude Code session sits next to a random SSH connection. Your Codex session is buried behind three other tabs. Every time you need to switch context, you are playing a game of hide-and-seek with your own terminals.

But the terminal chaos is only half the problem. The deeper issue is context fragmentation. Claude Code and Codex do not share memory. Every time you start a new session with either agent, it begins with zero knowledge of your project. You end up repeating the same explanations: "The project uses a monorepo with three packages. Authentication is handled by a custom JWT middleware. The database layer uses Drizzle ORM." This re-explanation tax adds up to significant wasted time across a workday.

The Beam Solution: Organized Workspaces + Shared Memory

Beam solves both problems with two features: workspaces for organization and project memory for shared context. The idea is simple. Create one dedicated workspace for each AI agent, with all the supporting terminals that agent needs grouped alongside it.

Workspace "Claude Code":

• Tab 1: Your active Claude Code session
• Tab 2: Dev server and file watcher (split pane for side-by-side output)
• Tab 3: Git operations for reviewing and committing Claude's changes

Workspace "Codex":

• Tab 1: Your active Codex CLI session
• Tab 2: Test runner to verify Codex's output in real time
• Tab 3: Logs and build output

With this layout, you switch between agents instantly using ⌘⌥←→ or by opening the Quick Switcher with ⌘P. Each workspace is a self-contained environment. When you are in the Claude Code workspace, everything you see is relevant to Claude's work. When you switch to the Codex workspace, you are in a completely different context. No mixing, no searching, no confusion.

Step-by-Step Dual-Agent Setup

1. Download and open Beam. If this is your first time, Beam walks you through the basics in a quick onboarding flow.
2. Create your first workspace. Press ⌘N to create a new workspace. Double-click the workspace name in the sidebar and rename it to "Claude Code."
3. Start Claude Code. In the first tab, navigate to your project directory and run claude to start a Claude Code session.
4. Add supporting tabs. Press ⌘T to add a new tab. Start your dev server in the second tab. Add a third tab for git. Use ⌘⌥⌃T to create split panes if you want side-by-side output.
5. Create the Codex workspace. Press ⌘N again to create a second workspace. Rename it to "Codex."
6. Start Codex. In the first tab of the new workspace, navigate to the same project directory and run codex to launch the Codex CLI.
7. Add Codex supporting tabs. Add tabs for your test runner (e.g., npm test -- --watch) and a log tail for build output.
8. Save the layout. Press ⌘S to save your entire dual-workspace layout. Tomorrow, when you sit down to work, restore it and everything is exactly where you left it -- both agent workspaces, all tabs, all splits.

Interoperable Memory: The Key to Multi-Agent Workflows

Beam's "Install Project Memory" feature creates a shared markdown file in your project root. This file serves as a persistent knowledge base that both Claude Code and Codex can read. For Claude Code, this integrates directly with its CLAUDE.md convention. For Codex, you can reference the same file as context when starting a session.

The memory file captures everything both agents need to know: your project architecture, the coding conventions your team follows, the file structure, key decisions and their rationale, and any gotchas or constraints. When Claude Code decides to restructure the authentication flow from session-based to JWT, you document that decision in the shared memory file. The next time you start a Codex session, it reads that file and immediately understands the new architecture without you typing a single word of explanation.

This is the real superpower of a multi-agent workflow: agents that build on each other's work instead of operating in isolation. Claude Code lays the architectural foundation and documents it. Codex picks up that documentation and executes the follow-up tasks with full awareness of what changed and why. The memory file acts as the connective tissue between two otherwise independent agents.

To keep the memory file useful, treat it like a living document. After every significant change either agent makes, spend thirty seconds updating the relevant section. The compound value of this habit is enormous -- within a few days, you have a rich project context file that eliminates the re-explanation tax entirely.

A Day with Both Agents: Example Workflow

Here is what a realistic dual-agent workday looks like for a developer building a SaaS application:

Morning -- Architecture with Claude Code. You open Beam, restore your saved layout, and switch to the Claude Code workspace. You have a complex task: redesign the authentication module to support OAuth providers alongside the existing email/password flow. This is exactly the kind of multi-file, multi-concern task where Claude Code shines. It analyzes your existing auth code, proposes a strategy, and methodically updates the middleware, route handlers, database models, and type definitions. You review the changes in the git tab as they happen.

Midday -- Update the memory file. Claude Code finishes the refactor. Before switching agents, you update the project memory file with the new auth architecture: what changed, what the new flow looks like, which files were added or modified, and any migration steps needed. This takes two minutes and saves twenty minutes of explanation later.

Afternoon -- Execution with Codex. You switch to the Codex workspace with ⌘⌥→. Codex reads the updated memory file and immediately knows about the new OAuth architecture. You point it at the test directory and ask it to update all authentication tests. Codex moves fast -- updating 30 test files, generating new test cases for the OAuth flow, and fixing type imports across the test suite. You watch the test runner in the adjacent tab confirm everything passes.

Evening -- Review with Claude Code. You switch back to the Claude Code workspace for a final review pass. Claude Code scans the full codebase for consistency: are all the new OAuth types used correctly? Did Codex miss any edge cases in the tests? Are the error messages consistent? Claude catches two minor issues and fixes them. You commit everything with confidence.

Throughout this entire day, Beam kept everything organized. You never once searched for a lost terminal, never re-explained the project to an agent, and never accidentally ran a command in the wrong session.

When to Use Which Agent

The general rule is straightforward. If the task requires deep reasoning about how multiple parts of your system interact, use Claude Code. If the task is well-defined and execution-focused, use Codex. If you are unsure, start with Claude Code for the planning phase and hand off to Codex for implementation of the individual pieces.

Over time, you will develop an intuition for which agent to reach for. The key insight is that this is not about one agent being "better" than the other. They have genuinely different strengths, and the developer who leverages both will consistently outperform the developer locked into a single tool.

Summary

Running Claude Code and Codex together on one project is one of the most effective ways to accelerate your development workflow in 2026. The key is organization and shared context. Here are the takeaways:

• Use Claude Code for reasoning and Codex for execution -- they complement each other perfectly
• Create dedicated Beam workspaces for each agent with their supporting terminals grouped together
• Switch between agents instantly with ⌘⌥←→ or the Quick Switcher (⌘P)
• Use Beam's project memory to share context between agents -- this eliminates the re-explanation tax
• Save your layout with ⌘S so your dual-agent setup restores instantly every morning
• Document architectural decisions in the shared memory file so both agents build on each other's work

The developers who figure out multi-agent workflows early will have a significant advantage. With the right organization, two AI agents are not twice as useful as one -- they are more than the sum of their parts.