Codex Verify

Codex Document Verification + Double-Check

You are a translator + executor + double-checker. The user wants an independent review of a plan or document. Your job is to hand the document to Codex without ever loading it into your own context, so your follow-up evaluation is genuinely independent.

For code review use /codex-review. For research use /codex-research.

Execution Contract

This contract overrides default exploration habits. Read it before Phase 1.

| Phase | Allowed | Forbidden | |-------|---------|-----------| | 1 ANALYZE | test -f/-s, wc -l/-c, file, echo, printf, cat "$DOC" >> "$PROMPT_FILE" (file-redirect, no stdout) | cat "$DOC" to stdout, head, tail, Read, Grep, Glob | | 2 INVOKE | Bash for companion launch via stdin pipe | All source / document reads to stdout | | 3 WAIT | status --wait loop (≤6 iterations, ≤24 min) | All reads, manual polling, ps/kill | | 4 DOUBLE-CHECK | Read the document (now — not before) to verify Codex's findings | n/a | | 5 REPORT + SAVE | Write report file | n/a |

Why the document stays out of context in Phase 1-3: if you read the document upfront, you form opinions before seeing Codex's. The double-check is then biased — you'll rationalize away valid catches. The blind-payload pattern (cat "$DOC" >> "$PROMPT_FILE") redirects to a file, not stdout, so your context stays clean.

Unknown flags silently become task prompt content (readTaskPrompt :613-619). Phase 1 is the only safety net.

---

Phase 1: Analyze + assemble blind payload

Parse $ARGUMENTS

Whitelist for this skill: --model , --effort (skill-level, route through apply-codex-config.py — never reach the companion). The document path is another skill input, not a companion flag.

Rules:

• A single path → treat as the document to verify.
• resume [follow-up] → pass --resume-last to the companion; the follow-up becomes the new prompt body.
• Multiple paths → AskUserQuestion which one.
• Meta-instructions addressed to YOU (e.g. "evaluate in Korean", "be strict" — often typed in the user's own language) → obey for your own behavior, never include in the prompt.
• No args → AskUserQuestion: "What document should I verify?"
• Unknown flags (e.g., --base, --write, --foo) → AskUserQuestion. verify has no companion flags to forward. --model/--effort are skill-level and route through apply-codex-config.py.
• --no-preview → skip Phase 1.5 draft review. Power users who trust the translation.

Resolve the document path

# Input validation only — never load content.
# Replace  with the path parsed from $ARGUMENTS.
test -f "" || { echo "File not found: " >&2; exit 1; }
test -s "" || { echo "File is empty: " >&2; exit 1; }
echo "DOC_LINES=$(wc -l ")"   # size info, not content

Assemble the blind payload

set -o pipefail
CODEX_COMPANION=$("${CLAUDE_PLUGIN_ROOT}/scripts/resolve-companion.sh") \
  || { echo "Official Codex plugin not found — run /codex-setup" >&2; exit 1; }

mkdir -p "${CLAUDE_PLUGIN_DATA}/tmp"
TS=$(date +%s%N)
PROMPT_FILE="${CLAUDE_PLUGIN_DATA}/tmp/verify-prompt-${TS}.txt"
JOB_JSON_FILE="${CLAUDE_PLUGIN_DATA}/tmp/verify-job-${TS}.json"
echo "PROMPT_FILE=$PROMPT_FILE"
echo "JOB_JSON_FILE=$JOB_JSON_FILE"

# Header via heredoc — no document content yet.
# block tags from official gpt-5-4-prompting (prompt-blocks.md); bodies adapted to this skill's output schema — re-sync the tag set if the official guide updates
cat > "$PROMPT_FILE" 
You are a brutally honest technical reviewer. Review the following document for
material issues that would cause implementation failure.
Focus areas:
- Logical gaps and unstated assumptions
- Missing error handling or edge cases
- Overcomplexity (is there a simpler approach?)
- Feasibility risks (what could go wrong?)
- Missing dependencies or sequencing issues
- Internal contradictions or ambiguous requirements

Return a structured verdict:
1. PASS or FAIL (with clear reasons)
2. Blocking issues (P1) — must fix before proceeding
3. Recommendations (P2) — non-blocking improvements
Be direct. No compliments. Just the problems.

Ground every finding in the document text. Cite specific sections.
Do not speculate about issues not evidenced in the document.

Review the entire document before finalizing.
Check for interactions between sections that may create contradictions.

EOF

# Append document via file redirect — stdout stays empty, context stays clean.
# Use the literal doc path, NOT a shell variable from a prior Bash call.
cat "" >> "$PROMPT_FILE"

# Close XML
printf '\n\n' >> "$PROMPT_FILE"

Apply model/effort (if either flag was provided)

Run after payload assembly, before Phase 2, so the companion sees the new config.toml:

python3 "${CLAUDE_PLUGIN_ROOT}/scripts/apply-codex-config.py" \
  "" \
  ""

Relay the Model: ... | Effort: ... stdout line verbatim; pass stderr advisories through. config.toml is global — the change affects every Codex invocation until changed again. Flag that to the user when values changed.

If neither flag was provided, still call with two empty strings so the user sees the current values in the same format.

Before Phase 2, also print the Parsed line:

Parsed: doc="docs/plan.md" (DOC_LINES=247), payload=PROMPT_FILE

Order: apply-codex-config.py output first, Parsed line second. Remember the literal PROMPT_FILE, JOB_JSON_FILE, and USER_DOC paths. They are needed in later phases.

For edge cases, read ${CLAUDE_PLUGIN_ROOT}/references/companion-usage.md §7 (ANALYZE rules) and §8 (blind-payload details).

---

Phase 1.5: Draft Review

Skip this phase entirely if --no-preview was parsed in Phase 1.

Before sending anything to Codex, show the user the verification prompt. The XML payload is already written to PROMPT_FILE (with the document blind-appended). Show the prompt structure — especially the focus areas — so the user can verify or customize the review framing.

Display the draft

Show the XML prompt header (everything except the `` body) in a fenced code block, plus document info:

```` Verification prompt to send to Codex:

You are a brutally honest technical reviewer. Review the following document for
material issues that would cause implementation failure.
Focus areas:
- Logical gaps and unstated assumptions
- Missing error handling or edge cases
- Overcomplexity (is there a simpler approach?)
- Feasibility risks (what could go wrong?)
- Missing dependencies or sequencing issues
- Internal contradictions or ambiguous requirements

Return a structured verdict:
1. PASS or FAIL (with clear reasons)
2. Blocking issues (P1) — must fix before proceeding
3. Recommendations (P2) — non-blocking improvements
Be direct. No compliments. Just the problems.

Ground every finding in the document text. Cite specific sections.
Do not speculate about issues not evidenced in the document.

Review the entire document before finalizing.
Check for interactions between sections that may create contradictions.

Document: docs/plan.md (247 lines) — blind-appended as ``

````

The XML block must reflect the exact content written to PROMPT_FILE (minus the document body). Do not summarize.

Ask for approval

Use AskUserQuestion exactly once:

• Question: "This verification prompt will be sent to Codex."
• Options:

1. "Approve — execute as shown"
2. "Needs changes"
3. "Cancel"

Handle the response

• Approve → proceed to Phase 2 with the current PROMPT_FILE.
• Needs changes → the user will describe what to change. Common

edits: reword focus areas, add domain-specific review criteria, remove irrelevant focus areas, change the review tone. Rewrite PROMPT_FILE with updated XML header, re-append the document via blind redirect, then re-display and re-ask. No loop limit.

• Cancel → clean up PROMPTFILE and JOBJSON_FILE, stop execution.

---

Phase 2: Invoke (Pattern B — stdin pipe to task --background)

# NEVER pass a positional arg — readTaskPrompt short-circuits on
# positionalPrompt (:619), silently dropping the entire blind payload.
cat "" | node "$CODEX_COMPANION" task --background --json \
  > "" 2> ".stderr" \
  || { echo "task launch failed:" >&2; cat ".stderr" >&2; exit 1; }

# Capture jobId (node, not python — avoid host assumptions)
JOB_ID=$(node -e 'const fs=require("fs");try{const j=JSON.parse(fs.readFileSync(process.argv[1],"utf8"));if(!j.jobId)throw new Error("no jobId");process.stdout.write(j.jobId);}catch(e){process.stderr.write("JOB_ID parse failed: "+e.message+"\n");process.exit(1);}' "") \
  || { echo "raw companion stdout:" >&2; cat "" >&2; exit 1; }
echo "JOB_ID=$JOB_ID"

Remember the literal JOB_ID for Phase 3-4.

---

Phase 3: Wait (status --wait loop)

Each call blocks ≤4 min. Re-call on timeout. Cap at 6 iterations (24 minutes).

# Repeat until status is "completed" or "failed", or cap hit.
node "$CODEX_COMPANION" status --wait "" \
  --timeout-ms 240000 --json

• status === "completed" → fetch result
• status === "failed" → categorize per §6, save failure report
• waitTimedOut === true with queued/running → re-call
• 6 iterations exhausted → wait-timeout (§6). Show JOB_ID, suggest /codex:status .

Fetch result:

node "$CODEX_COMPANION" result "" --json

Full error table: ${CLAUDE_PLUGIN_ROOT}/references/companion-usage.md §6.

---

Phase 4: Double-check with verdict

Now you read the document. Not before.

Read ${CLAUDE_PLUGIN_ROOT}/references/evaluation.md (Peer AI Evaluation + Self-Bias Awareness).

Self-bias warning: if Claude authored the document (same session), acknowledge it: "Note: I authored this — extra honesty required." Don't rationalize away valid catches.

For each of Codex's findings:

• Valid catch — "Codex caught this. I missed it during planning."

Read the cited document section to confirm.

• Already considered — "I considered this: [reason]." Cite the

document section that addresses it.

• False Positive (hallucination) — Codex cited a document section

that does not exist, or misread what the section says. Read the cited section to confirm.

• Uncited — no concrete section reference. Surface as "verification

deferred". Never invent citations.

Produce the verdict

## Verification Result: PASS / FAIL

### Blocking Issues (P1 — must fix before proceeding)
- [issue]: [why it's blocking]

### Recommendations (P2 — non-blocking)
- [suggestion]: [why it would be better]

### False Positives
- [finding]: [why it's not a real issue]

### Agreement:  (N/M findings)

FAIL if any P1 issue exists. PASS if only P2 or none.

---

Phase 5: Report + save

mkdir -p "${CLAUDE_PLUGIN_DATA}/reviews"

Success: save to ${CLAUDE_PLUGIN_DATA}/reviews/verify-.md with:

• The document path
• Codex's output verbatim
• Per-finding classification with document citations
• Final verdict (PASS / FAIL)

Failure: save to ${CLAUDE_PLUGIN_DATA}/reviews/verify--failed.md with the §6 error category, stderr, and the document path.

Clean up temp files using the literal paths captured in Phase 1:

rm -f "" "" ".stderr"

---

Gotchas

• Never Read the document before Phase 4. The blind-payload pattern

preserves double-check independence. Reading in Phase 1 defeats the entire purpose of the skill.

• cat "$USER_DOC" >> "$PROMPT_FILE" — file redirect keeps stdout

empty. cat "$USER_DOC" alone would dump content into Claude's context. The >> "$PROMPT_FILE" is load-bearing.

• Never pass a positional argument with Pattern B's stdin pipe.

readTaskPrompt short-circuits on positionalPrompt || readStdinIfPiped() (:619); a positional silently drops the entire blind payload.

• set -o pipefail is mandatory. Without it, a cat-side failure

sends 0 bytes and the companion's prompt-empty error masks the root cause.

• Temp file paths must come from Phase 1 stdout. Do not rely on

$PROMPT_FILE / $JOB_JSON_FILE variables in later Bash calls — Bash spawns a fresh shell each call. Re-inject literal absolute paths.

• Claude has bias reviewing its own work. If the document was

authored in this session, be extra honest. Don't rationalize valid catches.

For the full shared gotchas list, read ${CLAUDE_PLUGIN_ROOT}/references/companion-usage.md §10.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: LeeJuOh
• Source: LeeJuOh/claude-code-zero
• License: MIT

Install and usage instructions live in the source repository linked above.