Codex Code Review

Run OpenAI Codex CLI to review code changes or implementation plans.

Mode Detection

Determine which mode to use based on what the user wants reviewed:

Mode A — Code Diff Review (

codex review

)

Use when the user wants to review actual code changes (committed or uncommitted).

Indicators: "review my changes", "review this PR", "review the diff", or no specific context (default).

Mode B — Plan / Design Review (

codex exec

)

Use when the user wants to review a plan, design, or suggested implementation that exists in conversation context — NOT as code diffs.

Indicators: "review the suggested implementation", "review this plan", "review the design", "review what was proposed", or when there are no relevant code changes on the branch.

Compact Prompt

Always pass a compact-output instruction via heredoc stdin to reduce context window usage.

codex review

does NOT accept a prompt as a positional argument alongside flags, but it does read from stdin via heredoc.

COMPACT_PROMPT="Be concise. For each finding output ONLY: severity (critical/warning/info), file:line, and a one-line description. Group by severity. No code snippets unless critical. No preamble or summary paragraph."

Mode A — Code Diff Review

1. Run

   git status

   to check for uncommitted changes

2. Choose the appropriate review target:

   Uncommitted changes (staged, unstaged, or untracked):

   codex review --uncommitted <<'EOF'
   $COMPACT_PROMPT
   EOF
   

   Specific commit SHA:

   codex review --commit <SHA> <<'EOF'
   $COMPACT_PROMPT
   EOF
   

   Base branch comparison:

   codex review --base <BRANCH> <<'EOF'
   $COMPACT_PROMPT
   EOF
   

   No uncommitted changes — review latest commit:

   codex review --commit HEAD <<'EOF'
   $COMPACT_PROMPT
   EOF
   

3. Present the output and offer to help fix issues

Mode B — Plan / Design Review

Use

codex exec

in read-only sandbox mode. Pipe the plan text via stdin.

1. Collect the plan/design text from the conversation context

2. Write it to a temp file, then run:

   codex exec --sandbox read-only -o /dev/stdout - <<'PLAN_EOF'
   Review the following implementation plan for a codebase at $PWD.
   Identify issues, missing edge cases, security concerns, and incorrect assumptions.
   Be concise. List issues as bullet points with severity (critical/warning/info).
   
   --- PLAN ---
   <paste plan text here>
   PLAN_EOF
   

   Or if the plan references files that already exist, let codex read them:

   codex exec --sandbox read-only "$REVIEW_PROMPT"
   

   Where

   $REVIEW_PROMPT

   includes the plan text and instructions to read relevant files.

3. Present the output and offer to help address issues

Custom Instructions

If the user provides arguments (e.g. "focus on security"), prepend them to the compact prompt in the heredoc:

# Mode A
codex review --uncommitted <<'EOF'
Focus on security. $COMPACT_PROMPT
EOF

# Mode B
codex exec --sandbox read-only "focus on security. $REVIEW_PROMPT"

Notes

• The

  codex

  CLI must be installed and authenticated (

  codex login

  )
• Timeout should be generous (up to 5 minutes) as reviews can take time
• The compact prompt keeps output short; if the user wants full verbose output, they can say

  /codex-review --verbose

  and you should omit the heredoc
• For Mode B, always use

  --sandbox read-only

  since no writes are needed