Comparison · under IB-CODE-2026.2
OpenAI Codex CLI vs Grok Build
| OpenAI Codex CLI | Grok Build | |
|---|---|---|
| Vendor | OpenAI | xAI |
| Pricing | Included in ChatGPT Pro $200/mo; or raw API at GPT-5.5 rates | SuperHeavy intro $99/mo for first 6 months (then $299/mo); API at $0.20 / $1.50 per Mtok in/out |
| Default model | GPT-5.5 (GPT-5.5-mini available for cost-sensitive runs) | Grok 3.5 (Grok Build proprietary fine-tune); 256K context; 70.8% SWE-bench Verified |
| CLI surface | ✓ | ✓ |
| Eval status | queued | deferred |
Comparison pending — neither side evaluated yet
Both OpenAI Codex CLI and Grok Build are currently unevaluated under IB-CODE-2026.2. This page will update as evaluations land.
Want this comparison sooner? Vendors can commission an evaluation to bump their tool up the queue (with full editorial independence on the verdict). Readers can email hello@indiebench.dev to vote for which comparison ships next.
About each tool
OpenAI Codex CLI
The Codex name has a long history — the original 2021 Codex API (code-davinci-002) was deprecated in March 2023. The current Codex CLI is a complete re-architecture: GPT-5.5 backed, with Goal Mode for multi-hour autonomous runs, native subagents, MCP server support, plugin marketplace, browser verif…
Grok Build
Grok Build launched May 14 2026 in early beta — xAI's entry in the agentic coding CLI category. The novel feature is multi-agent arena mode: up to 8 concurrent sub-agents working on parallel branches with a coordinator selecting the best result. Pricing is the steepest in this list for individual us…