Claude Code vs Codex vs Gemini CLI: Which Coding Agent CLI Should You Choose?¶

Quick Answer: All five coding CLIs — Claude Code, Codex CLI, Gemini CLI, OpenCode, and Hermes — are competent at editing files. The differences that matter for daily work are model quality, context window management, and ecosystem lock-in. None of them ships durable cross-session project memory by default. If your work spans multiple sessions, multiple agents, or multiple clients, keep the CLI you like and add a local workflow layer (AIOS) underneath — it adds memory, routing, and verification without replacing the client.

The honest comparison¶

	Claude Code	Codex CLI	Gemini CLI	OpenCode	Hermes
Best at	Long, nuanced refactors	Repo-scale automation, GitHub-native	Breadth, multimodal reasoning	Open, configurable, model-agnostic	Open-source research agent
Model	Claude	GPT-5.x family	Gemini	Your choice	Nous Research models
Cross-session memory	None by default	None by default	None by default	None by default	None by default
Multi-agent orchestration	Ad-hoc	Limited	Limited	Plugins	Via MCP
Local-first	Yes	Yes	Yes	Yes	Yes

The table's empty "memory" row is the real story. Every major CLI is local-first and fast at editing. The thing none of them does by default is remember yesterday's decisions — which is exactly the gap a workflow layer fills.

When to pick which¶

Pick Claude Code for long, judgment-heavy refactors where the model's reasoning depth pays off.
Pick Codex CLI when you live in GitHub and want repo-scale automation with fewer moving parts.
Pick Gemini CLI when you want one tool that handles code plus broad multimodal tasks.
Pick OpenCode when you want maximum configurability and model freedom.
Pick Hermes when you want an open-source agent with an MCP bridge surface.

The missing row: memory and orchestration¶

Whatever you pick, the workflows that actually ship are rarely a single one-shot session. They are: a decision made on Tuesday, a follow-up on Friday, a parallel review by a second agent, a verification step before merge. None of the five CLIs coordinates that by itself.

That is what AIOS adds underneath:

ContextDB — cross-session project memory that works identically in all five clients (and grok).
Workflow Policy — direct / guarded / planned routing so the amount of process matches the risk.
Agent Team — fan out parallel agents and merge their evidence.
Solo Harness — resumable long-running runs with verification gates.

You keep the client you already chose; the layer is the same for all of them. See the CLI comparison for the deep dive.

FAQ¶

Which coding CLI is best in 2026? There is no single best — it depends on model preference and ecosystem. All five are production-usable; the differentiator is memory and orchestration, which none of them provides by default.

Can I use two coding CLIs on the same project? Yes. AIOS is client-neutral: the same .aios/context-db/ memory is available to codex, claude, gemini, opencode, hermes, and grok in the same project.

Do I have to migrate off Claude Code to use AIOS? No. AIOS is a layer under the client, not a replacement. Keep Claude Code (or any other) and add memory, routing, and verification.

Next step¶

Start with the Quick Start, or read the raw CLI vs AIOS comparison first.