Update (May 20, 2026): Google has replaced Gemini CLI with Antigravity 2.0 — a full platform rebuild with desktop app, Go-based CLI, and SDK. It now runs Gemini 3.5 Flash (289 tok/s, 4x faster than competitors). The comparison below still reflects the tool’s core capabilities, but the branding is now “Antigravity CLI” and the model is significantly upgraded.

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The three major AI coding agents — Claude Code, OpenAI Codex CLI, and Gemini CLI — have all shipped major updates in April 2026. Claude Code got Routines (cloud automation). Codex got the Agents SDK with sandbox execution. Gemini CLI got subagents with parallel delegation.

This updates our earlier comparison with the latest capabilities.

Feature comparison (April 2026)

Feature	Claude Code	Codex CLI	Gemini CLI
Context window	1M tokens	200K tokens	1M+ tokens
Subagents	✅ Natural language	✅ Via Agents SDK	✅ Custom Markdown files
Parallel execution	✅	✅	✅
Sandbox	❌ (runs locally)	✅ Native (Docker, Cloudflare)	❌ (runs locally)
Cloud automation	✅ Routines	❌	❌
Custom agents	❌	✅ (code any agent)	✅ (Markdown definitions)
Tool restriction	Permission system	Per-agent tools	Per-agent tools
MCP support	✅ Native	✅ Via SDK	✅ Native
Model	Claude Sonnet/Opus	GPT-4o/o3	Gemini 2.5 Pro/Flash
Pricing	$20/mo (Pro) or API	API usage	Free (with Google account)

What changed in April 2026

Claude Code: Routines

Claude Code Routines let you schedule automated tasks that run in Anthropic’s cloud. Daily code reviews, weekly dependency audits, post-deployment checks — all without your laptop open. No other coding agent has this.

The trade-off: Claude Code still runs locally for interactive sessions. There’s no sandbox isolation — it has full access to your filesystem. You trust Claude not to break things.

Codex CLI: Agents SDK + Sandbox

The OpenAI Agents SDK update gives Codex proper sandbox execution. Agents can write and run code in isolated Docker containers or Cloudflare Sandboxes. This is the most secure option for autonomous code execution.

The trade-off: more setup required. You need to configure sandboxes, define tools, and manage the agent lifecycle yourself.

Gemini CLI: Subagents

Gemini CLI subagents are the most customizable. Define specialist agents as Markdown files with custom system prompts, restricted tools, and even different models per agent. The @agent-name syntax makes delegation explicit.

The trade-off: Gemini CLI is the newest and least battle-tested of the three.

Real-world performance

Based on using all three for daily coding work:

Claude Code is the best for complex, multi-file refactoring. The 1M token context window means it can hold an entire codebase in memory. The /compact and /rewind commands give you fine-grained control over context management. It’s the most “senior developer” of the three.

Codex CLI is the best for autonomous tasks where you want isolation. The sandbox means you can tell it “build and test this feature” and walk away, knowing it can’t accidentally delete your production database. Best for CI/CD integration and automated workflows.

Gemini CLI is the best value. It’s free with a Google account, supports custom subagents, and Gemini 2.5 Pro is competitive with Claude Sonnet on most coding tasks. The subagent customization (Markdown files with tool restrictions) is the most elegant implementation.

Pricing comparison

	Claude Code	Codex CLI	Gemini CLI
Free tier	❌	❌	✅ Generous
Pro plan	$20/mo (Pro)	Pay-per-token	Free
Heavy usage	$100/mo (Max) or API	$50-200/mo API	Free (rate limited)
Enterprise	Team plan	Enterprise API	Google Cloud

For budget-conscious developers, Gemini CLI is hard to beat at $0. For maximum capability, Claude Code Pro at $20/month is the best value per dollar. For production automation, Codex CLI’s pay-per-token model scales predictably.

Which one for your use case

Use case	Best choice	Why
Daily coding assistant	Claude Code	Best context management, most capable
Automated CI/CD agent	Codex CLI	Sandbox isolation, API-first
Budget-friendly coding	Gemini CLI	Free, good quality
Multi-agent workflows	Gemini CLI	Custom subagents
Cloud automation	Claude Code	Routines (unique feature)
Security-sensitive code	Codex CLI	Sandbox isolation
Open-source projects	Gemini CLI	Free, no API costs

Using multiple agents

Many developers use two or three:

# Morning: complex architecture work with Claude
claude "Refactor the payment module to support subscriptions"

# Afternoon: routine tasks with free Gemini
gemini "Add input validation to all API endpoints"

# CI/CD: automated testing with Codex
codex --sandbox "Run the full test suite and fix any failures"

Total cost: $20/month (Claude Pro) + $0 (Gemini) + usage-based (Codex). This gives you frontier quality for hard problems, free capacity for routine work, and sandboxed execution for automation.

FAQ

Which AI agent is best?

Claude Code is best for complex coding and context management with its 1M token window. Codex CLI is best for automated workflows requiring sandbox isolation. Gemini CLI is best for budget-conscious developers — it’s free and supports custom subagents. Most developers benefit from using two or three depending on the task.

Is Gemini CLI free?

Yes. Gemini CLI is free with a Google account, including access to Gemini 2.5 Pro and custom subagents. There are rate limits on heavy usage, but for most individual developers the free tier is generous enough for daily work. This makes it the best value among the three major coding agents.

Can agents replace developers?

Not yet. AI coding agents handle well-defined implementation tasks effectively, but they still need human guidance for ambiguous requirements, architectural decisions, and business logic. The current sweet spot is delegating routine coding to agents while developers focus on design, review, and decision-making. Think of agents as force multipliers, not replacements.

Related: Claude Code vs Codex CLI vs Gemini CLI (original) · How to Use Claude Code · Gemini CLI Subagents · OpenAI Agents SDK Guide · Claude Code Routines · AI Coding Tools Pricing