Cross-Model Code Review with Codex CLI

Cross-model validation using the codex binary directly. Claude writes code, Codex reviews it. Different architecture, different training distribution, no self-approval bias.

Core insight: Single-model self-review is systematically biased. Cross-model review catches different bug classes because the reviewer has fundamentally different blind spots than the author.

How to read this skill: the patterns and decision trees below are guidelines. Pick what fits, blend when needed. The rules marked ⚠️ are different: they're real codex CLI behaviors, not procedural ceremony. Skipping the scope flag genuinely hangs the call; piping to tail genuinely loses output. Treat ⚠️ rules as facts about the tool, not opinions about workflow.

Prerequisite: The codex CLI must be installed and authenticated. Verify with codex --version. User defaults live in ~/.codex/config.toml; respect them.

On Pi: when the pi-nova xreview extension is installed, prefer /xreview — it wraps external codex exec --sandbox read-only with stdin closed and returns structured Verdict/Findings/Fix Queue. Manual bash calls from Pi follow the same ⚠️ rules below.

Direction: Claude → Codex only. For the bidirectional skill (also handles Codex → Claude with the claude -p gotchas around yield_time_ms and variadic flags), use /hyperskills:cross-model-review instead.

⚠️ Non-Negotiable Rule: Always pass a scope flag to codex review

A bare codex review (no scope) is the #1 cause of failures: it hangs or produces 100KB+ blob output. Always specify exactly one scope flag: