The five-line pick
You're one person shipping an app, and the coding agent you pick decides how far one monthly bill gets you.
Already pay for Claude Pro? Start with Claude Code. It's included, and your chats and your coding share one usage pool.
Already on ChatGPT Plus? Codex is included at $20 a month, with cloud tasks and GitHub code review built in.
Watching every dollar? Muse Code runs on Meta's cheaper Muse Spark model, with plans from $15 a month or pay per token.
Running more than one agent? Buzz, Block's open-source workspace, lets you swap Claude Code, Codex and others behind one place, but skip it if you just want to code today.
Why the wrapper matters (the "harness" point)
The model is the brain. The harness is everything around it: how it reads your files, runs commands, checks its own work and decides when it's done. Tests keep showing the same model scoring differently in different harnesses. In PawBench (June 2026, 9 models across 3 harnesses on 150 tasks), a small open model moved 11.5 points depending only on the harness, while Claude Opus 4.6 moved just 2.3 points.
What that means for you: on a frontier model, the harness changes your day more than your score. On a cheaper model, the harness can be the difference between "works" and "doesn't". So pick the agent whose workflow you like, then pick the plan.
Who each one is for
- Claude Code suits you if you already use Claude for writing or planning. Skip it if you hate hitting a weekly cap mid-project. Usage resets on a rolling five-hour window with weekly limits on paid plans, and chat use counts against the same pool.
- Codex suits you if you live in ChatGPT and GitHub and want the agent to review pull requests or run tasks in the cloud. Skip it if you only want a local terminal tool and never touch ChatGPT.
- Muse Code suits you if cost per task matters most and you're fine on Mac or Windows. Skip it if you need Linux today, or if you don't want your code used to improve Meta's products (that depends on which model you pick; the cheapest "contributor" model is used for training).
- Buzz suits you if you already run several agents and want one shared place with channels, repos and a single audit trail. Skip it if you're one person with one agent. It is a workspace for agents, not a coding agent itself, and its Git features are still early by Block's own account.
Pricing and usage limits (checked 2026-09-25)
| Entry paid plan | Heavier plan | Pay per use | Where the limit bites | |
|---|---|---|---|---|
| Claude Code | Included in Claude Pro, $20/mo monthly ($17/mo billed annually) | Max from $100/mo (5x or 20x Pro usage) | API credits via a Console account | Five-hour window plus weekly limits, shared with chat |
| Codex | Included in ChatGPT Plus, $20/mo | Pro from $100/mo (5x or 20x Plus usage) | API key at API rates (no cloud features) | Five-hour window, weekly limits may apply; buy credits to keep going |
| Muse Code | High Usage $15/mo (5x Everyday) | Power Usage $50/mo (20x Everyday) | muse-spark-1.2: $1.25 in / $4.25 out per million tokens | Everyday plan: 10 to 50 prompts per five hours |
| Buzz | Open source (Apache-2.0), self-host | Hosted option at buzz.xyz | You pay for whichever agent you plug in | Depends on the agent behind it |
Codex's Free and Go ($8/mo) plans also include Codex, limited to one lighter model in the desktop app. Muse Code's Everyday price isn't shown on Meta's public pages; Meta shows it at checkout, so we left it out.
Give this to your agent
I'm a solo builder choosing a coding agent. Read https://usesoloai.com/agents/ai-coding-agents-for-solo-builders/ .
1. Ask me which subscriptions I already pay for (Claude, ChatGPT, none).
2. Ask whether I work on Mac, Windows or Linux, and whether code privacy matters.
3. Recommend ONE agent from the page and the cheapest plan that fits.
4. Before I pay, open the official pricing page linked on that page and confirm the price is still current.
5. Install it, run one small task in my repo, and tell me how much of my usage limit it used.
Before you ship
Once your agent has built something, run the vibe-coded app security checklist. It is one prompt that checks row access, secrets, Stripe webhooks, and paid AI endpoints, and ends with SHIP or NO-SHIP.
Sources
- Claude pricing and usage FAQ: https://claude.com/pricing
- Codex pricing and limits: https://developers.openai.com/codex/pricing
- Muse Code product page: https://developer.meta.com/ai/products/muse-code/
- Muse Code subscriptions: https://ai.developer.meta.com/docs/muse-code/subscriptions
- Muse Spark 1.2 pay-as-you-go rates: https://developer.meta.com/ai/resources/blog/build-with-muse-code/
- Buzz announcement: https://block.xyz/inside/introducing-buzz-where-humans-and-agents-work-together
- Buzz repo and harness bridge: https://github.com/block/buzz
- PawBench harness results: https://github.com/agentscope-ai/PawBench
- Bookmarked posts that started this: https://x.com/finkd/status/2085080750034940201 and https://x.com/ArchiveExplorer/status/2073004382187110510
No affiliate links. Prices checked against the official pages above on 2026-09-25.