Claude Code vs Codex vs OpenCode: the terminal agents compared

Codex vs Claude Code: the short version

Codex CLI is OpenAI's open-source terminal agent (npm install -g @openai/codex). It drives OpenAI's coding models, runs with a configurable sandbox — read-only, workspace-write or full access — and has a non-interactive codex exec mode for scripts. Usage is included in ChatGPT Plus, Pro and Team plans or billed through an OpenAI API key. Claude Code is the same shape with a different brain: Claude models only, a proprietary CLI, and a larger surface — subagents, hooks, skills, plugins, MCP resources, the GitHub Action and the Agent SDK.

In practice the differences people notice are: Claude Code's planning and long-task persistence versus Codex's tighter sandbox defaults; Claude Code's permission prompts versus Codex's approval modes; and cost, which is almost entirely a function of which plan or API sits underneath.

OpenCode vs Claude Code

OpenCode is the open-source option: a terminal agent under a permissive licence, provider-agnostic, with a TUI that will feel familiar to Claude Code users. It supports Anthropic-compatible endpoints natively, so a gateway key works by adding a provider with the base URL. What it lacks is the ecosystem — no official skills marketplace, GitHub Action or Agent SDK — and it moves fast, so expect churn. If you want to read the source of your agent, or switch models per task, it is the right pick.

Side by side

• Models — Claude Code: Claude only. Codex: OpenAI only. OpenCode: any provider.
• Open source — Claude Code: no (SDK and Action are). Codex: yes. OpenCode: yes.
• Headless / CI — Claude Code: claude -p, GitHub Action, Agent SDK. Codex: codex exec, GitHub integration. OpenCode: non-interactive mode.
• Extensibility — Claude Code: subagents, hooks, skills, plugins, MCP. Codex: MCP, config profiles. OpenCode: MCP, custom providers.
• Sandboxing — Codex: strongest defaults. Claude Code: permission prompts + --allowedTools. OpenCode: permission prompts.
• Billing — Claude Code: Pro/Max or API. Codex: ChatGPT plan or API. OpenCode: whatever provider you configure.
• Custom endpoint — Claude Code: ANTHROPIC_BASE_URL. Codex: OpenAI-compatible base URL. OpenCode: per-provider base URL.

Why the backend matters more than the agent

The agents converge on the same loop; the model and its price are what you actually experience. A Claude Code session and an OpenCode session on the same Claude model, through the same endpoint, produce similar work at a similar cost. Change the endpoint and the cost changes for both: on this gateway, Claude usage is bought at 7.69× face value or as a flat-rate plan, and both Claude Code and OpenCode use it with one variable each.

# Claude Code
export ANTHROPIC_BASE_URL=https://aiprimetech.io
export ANTHROPIC_API_KEY=your_gateway_key

# OpenCode: add an Anthropic-type provider with the same base URL and key
# (Provider settings -> Anthropic -> Base URL: https://aiprimetech.io)

Codex CLI is the exception: it speaks OpenAI's API shape and needs OpenAI models, which this gateway does not serve. Use it with its own plan or key.

Choosing

• Pick Claude Code if you want the most complete agent tooling and are happy with Claude models.
• Pick Codex if your team is on ChatGPT plans, wants OpenAI models, or values the sandbox defaults.
• Pick OpenCode if open source or per-task model switching matters more than ecosystem.
• Run two: many teams keep Claude Code as the default and a second agent for a second opinion on hard bugs.

Frequently asked questions

AI Prime Tech is an independent API gateway and is not affiliated with, endorsed by, or sponsored by Anthropic. “Claude” and “Claude Code” are trademarks of Anthropic. Claude Code features described here follow Anthropic’s public documentation at the time of writing and change frequently; prices and model lists on this page are read from this gateway’s live settings.