OpenAI Codex vs Sunk Cost (2026): Which Vibe Coding App Is Better?
Both are popular terminal coding agents. Here is how OpenAI Codex and Sunk Cost stack up on price, strengths and weaknesses, and which one we would pick.
OpenAI Codex
OpenAI's coding agent for the terminal, IDE and cloud, included with ChatGPT plans
9.1 /10
Pricing: Free plan, paid from $8/mo
Pros
- Included with ChatGPT plans you may already pay for
- Open-source CLI plus cloud tasks that open pull requests
- Reads AGENTS.md, the cross-tool instructions file
Cons
- Fewer extension points than Claude Code (no plugin marketplace)
- Usage limits depend on your ChatGPT plan
Sunk Cost
How long until a local LLM rig pays for itself?
6.5 /10
Pricing: Free
Pros
- Free, no signup, no cookies or IP logging
- Grounds the "buy hardware and run locally" debate in real numbers: hardware price, power draw and token throughput
- Includes a model capability leaderboard and hardware pricing database for context
Cons
- A single-purpose calculator, not an actual coding agent or MCP tool
- Estimates depend on self-reported hardware/pricing data and usage assumptions
OpenAI Codex vs Sunk Cost at a glance
| OpenAI Codex | Sunk Cost | |
|---|---|---|
| Editor score | 9.1 / 10 | 6.5 / 10 |
| Pricing model | Freemium | Free |
| Starting price | $8/mo | Free |
| Reader upvotes | 1 | 0 |
| Best for | terminal, agent, openai | local-llm, cost-calculator, hardware |
| Agent Skills support | Yes | No |
| Subagents support | Yes | No |
| MCP support | Yes | No |
| AGENTS.md support | Yes | No |
| Plugins support | No | No |
| Hooks support | No | No |
| Rules support | No | No |
| Agent skills in this directory | 58 | 0 |
| Subagents & agents in this directory | 43 | 3 |
| MCP servers in this directory | 74 | 0 |
Our pick
OpenAI Codex edges it with a score of 9.1 versus 6.5. OpenAI Codex is the better fit if you value: included with chatgpt plans you may already pay for, open-source cli plus cloud tasks that open pull requests. Choose Sunk Cost instead if you need: free, no signup, no cookies or ip logging, grounds the "buy hardware and run locally" debate in real numbers: hardware price, power draw and token throughput.
Other terminal coding agents to consider
Full ranking →Claude Code Paid
Anthropic's agentic coding tool for the terminal, IDE, desktop and web
🔥 Claude Pro billed annually: $17/month instead of $20OpenCode Open source
Open-source terminal coding agent that works with any model provider
Amp Freemium
Frontier coding agent for the terminal and editor, from the makers of Sourcegraph
Orca Open source
An ADE for running fleets of coding agents in parallel worktrees, from desktop or mobile