Co Validate

Co-Validate: Get a Staff Engineer Review of Your Plan

Arguments

$ARGUMENTS should be the path to the plan file. If not provided, check if there is a plan file from the current session (for example in ~/.claude/plans/ or the working directory).

How Codex Is Reached

Codex runs through its CLI, driven by the helper script scripts/codex-session, which lives two levels above this skill's base directory: call it as <base directory>/../../scripts/codex-session. It keeps one Codex conversation per session folder and always runs Codex in its read-only sandbox:

• codex-session new <label> makes a session folder and prints its path
• codex-session run <DIR> sends <DIR>/prompt.md as the first message and waits for the reply
• codex-session read <DIR> prints Codex's latest reply
• codex-session reply <DIR> sends a follow-up read from stdin and prints the reply

Shell variables do not survive between Bash calls, so always use the literal folder path.

Step 1: Start Codex and Hand It to a Background Subagent

Read the plan file, and find the original user prompt that led to the plan in the conversation history. Paste the original request between the tags below; the plan file itself is appended after the prompt with cat, not pasted.

1. Create the session and write Codex's first message, in one Bash call:

   DIR="$(<base directory>/../../scripts/codex-session new co-validate)" && echo "$DIR"
   cat > "$DIR/prompt.md" <<'CODEX_PROMPT'
   You are a staff engineer reviewing this plan. Analyze it for critical issues, big simplifications, or a completely different better approach, reading the code in the working directory where it helps — but do NOT share your review yet. If you need to ask clarifying questions about the plan or original request before reviewing, ask them now. Otherwise, when your review is complete and fully formed, respond with exactly: "My review is complete and I'm ready to present" and nothing else. Wait for my next message before sharing your review.
   
   Original request from the user:
   <original_request>
   {paste the user's original prompt/request that triggered the plan}
   </original_request>
   
   Plan:
   CODEX_PROMPT
   cat "<path to the plan file>" >> "$DIR/prompt.md"

2. Spawn a background subagent (Agent tool with run_in_background: true) to handle all communication with Codex. Give it the helper path and the folder path, and tell it to:

   1. Run <helper> run <DIR> in the foreground, with the Bash tool's longest timeout (600000 ms). It can take several minutes.
   2. Run <helper> read <DIR>. If Codex replied "My review is complete and I'm ready to present", go to step 4.
   3. If Codex asked clarifying questions instead, answer them using its own judgment and the code in the working directory, by sending a follow-up (quote the heredoc delimiter): <helper> reply <DIR> <<'CODEX_PROMPT' … CODEX_PROMPT. Then check the reply again as in step 2. If Codex sent its full review instead of the ready message, treat it as ready.
   4. Report back only that Codex is ready, the session folder, and how many questions it answered. Do NOT request or repeat Codex's review; that happens in Step 3.

   The subagent handles the back-and-forth so you are free to do your own work. In a non-interactive session (claude -p), do these steps yourself in the foreground instead: background work is killed when that kind of session ends.