Kiro CLI
If you want the agent to plan before it codes — requirements, design, then tracked tasks — Kiro's spec-driven flow and multi-model routing are unmatched. Ideal for shipping maintainable, reviewable work.
Updated July 2026 · Independent comparison
Best AI Coding Agents 2026
Three agents dominate the terminal in 2026: Kiro CLI, Claude Code, and Codex CLI. We compare their models, pricing, and features head-to-head — with a full matrix and a straight verdict.
Jump to the comparison matrix ↓ The verdict
Which one should you pick?
All three are excellent. The right choice comes down to how you like to work — plan-first, terminal-deep, or cloud-parallel.
Claude Code
For long, autonomous, multi-file sessions in a pure terminal workflow with the strongest Claude models and a 1M-token context, Claude Code is the deepest agent — if you can live with no free tier.
Codex CLI
Already paying for ChatGPT Plus or Pro? Codex is effectively free to add, runs tasks in parallel cloud sandboxes, and is the only open-source CLI of the three — great for delegation and review.
The contenders
Meet the three agents
Kiro CLI
Amazon (AWS)Spec-driven engineering rigor
Turns a vague idea into structured requirements, a design, and tracked tasks before writing code. Multi-model with automatic routing.
Full Kiro CLI review →Claude Code
AnthropicThe terminal-native powerhouse
Runs directly in your terminal, understands the whole codebase, and executes long autonomous multi-file edits with best-in-class Claude models.
Full Claude Code review →Codex CLI
OpenAICloud-parallel, open-source CLI
Delegate tasks to isolated cloud sandboxes, review PRs, and drive work from the terminal, IDE, or mobile. The CLI itself is open source.
Full Codex CLI review → Head-to-head
The comparison matrix
Highlighted cells mark where a tool clearly leads.
| Kiro CLI | Claude Code | Codex CLI | |
|---|---|---|---|
| Developer | Amazon (AWS) | Anthropic | OpenAI |
| Models | Multi-model: Claude Opus/Sonnet, Qwen, DeepSeek + Auto routing | Claude Sonnet 5 (default), Opus 4.8, Sonnet 4.6 | GPT-5-Codex (latest GPT-5.3-Codex) |
| Model choice | Yes — pick any, or Auto | Claude only | OpenAI only |
| Context window | Up to 1M (model-dependent) | 1M tokens (Sonnet 5) | GPT-5 class (large) |
| Free tier | Yes — 50 credits/mo | No — Pro required | Yes — Free & Go (limited) |
| Entry paid plan | Pro $20/mo (1,000 credits) | Pro $20/mo ($17 annual) | ChatGPT Plus $20/mo |
| Top individual tier | Power $200/mo | Max 20x $200/mo | ChatGPT Pro $200/mo |
| Overage / heavy use | $0.04 / credit PAYG | API pay-per-token | API token PAYG (since Apr 2026) |
| Spec-driven workflow | Native (requirements → design → tasks) | Plan mode | Task plans |
| Surfaces | IDE + CLI | CLI-first | App + CLI + IDE + cloud + mobile |
| Cloud sandbox / remote | Local execution | Background agents | Cloud sandbox + mobile remote (GA) |
| MCP support | Yes | Yes | Yes |
| Agent Skills (SKILL.md) | Yes | Yes — originator | Yes |
| Open-source CLI | No | No | Yes |
| Platforms | Windows · macOS · Linux | macOS · Linux | Win · macOS · Linux · iOS · Android |
| Best for | Structured, spec-first engineering | Autonomous terminal power users | Parallel cloud delegation + review |
Models
What powers each agent
Kiro CLI — flexible by design
Kiro is the only one of the three that lets you swap models per task. Reach for high-reliability Claude Opus on complex architecture, ultra-efficient Qwen or DeepSeek for long budget sessions, or select Auto to let Kiro route each task to the optimal model.
Claude Code — one model, taken deep
Claude Code runs Anthropic's own stack: Claude Sonnet 5 as the default with a native 1M-token context window, plus Opus 4.8 for the hardest reasoning. No model picking — just consistently strong output.
Codex CLI — GPT-5-Codex
Codex is tuned around OpenAI's GPT-5-Codex (latest snapshot GPT-5.3-Codex), a coding-specialized GPT-5 variant. The model snapshot updates regularly, and the same limits apply across the CLI, IDE, cloud, and app.
Pricing
Every plan, side by side
Prices are per user, per month, as of July 2026. Always confirm on the vendor's site.
Kiro CLI
Credit-based. The free plan is genuinely usable; paid tiers add pay-as-you-go credits.
- Free $0 50 credits · open-weight models + Claude Sonnet 4.5
- Pro $20/mo 1,000 credits · premium models
- Pro+ $40/mo 2,000 credits · premium models
- Pro Max $100/mo 5,000 credits · premium models
- Power $200/mo 10,000 credits · premium models
Paid tiers add pay-as-you-go credits at $0.04 / credit.
Claude Code
No standalone price and no free tier — bundled into a Claude subscription or billed per token via the API.
- Pro $20/mo $17/mo billed annually
- Max 5x $100/mo 5× the Pro usage ceiling
- Max 20x $200/mo 20× ceiling, early access
- Team $25–125/seat Standard / Premium
- API usage $1–25 / MTok, pay-per-token
There is no free Claude Code tier — you need at least Pro or API credits.
Codex CLI
No separate price — access is bundled into whatever ChatGPT plan you have.
- Free / Go included Limited, limited-time
- Plus $20/mo 10–60 cloud tasks per 5h window
- Pro $200/mo Highest included limits
- Business per-seat Team workspaces
- Enterprise / Edu custom Org-wide
Since Apr 2, 2026, extra usage is billed by API token usage, not per-message.
FAQ
Common questions
Which AI coding agent CLI is best in 2026?
There is no single winner — it depends on your workflow. Kiro CLI wins for structured, spec-driven engineering and model flexibility; Claude Code wins for deep autonomous terminal work; Codex CLI wins for parallel cloud delegation and value if you already pay for ChatGPT.
Which one is cheapest or free?
Kiro CLI has a real free tier (50 credits/month, including Claude Sonnet 4.5). Codex is included with ChatGPT Free and Go for a limited time and costs nothing extra if you already subscribe. Claude Code has no free tier and requires at least a $20/mo Pro plan or API credits.
Which has the best models?
Claude Code runs Anthropic's Claude Sonnet 5 (1M-token context) and Opus 4.8. Codex CLI runs OpenAI's GPT-5-Codex. Kiro CLI is the only one that lets you choose — Claude, Qwen, or DeepSeek — or let Auto route each task to the best model.
Are any of them open source?
Only the Codex CLI is open source. Kiro CLI and Claude Code are proprietary, though all three support the open MCP (Model Context Protocol) standard for connecting external tools.
Can I run them without an IDE?
Yes — all three are true command-line agents. Kiro and Codex also ship IDE integrations, and Codex adds a desktop app, cloud sandbox, and mobile remote control. Claude Code is the most terminal-first of the three.
How we compare. Facts are drawn from each vendor's official pricing and documentation and cross-checked against current reporting, last verified in July 2026. Pricing and model line-ups in this space change fast — treat this as a living page and confirm details before you buy.
Explore full reviews: Kiro · Claude Code · Codex · all coding tools →