Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/fidpa/codex-sandbox-toolkitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/commands/fidpa/codex-sandbox-toolkit/codex-crosscheck)<a href="https://agentmods.dev/commands/fidpa/codex-sandbox-toolkit/codex-crosscheck"><img src="https://agentmods.dev/badge/commands/fidpa/codex-sandbox-toolkit/codex-crosscheck/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/commands/fidpa/codex-sandbox-toolkit/codex-crosscheck"><img src="https://agentmods.dev/badge/commands/fidpa/codex-sandbox-toolkit/codex-crosscheck.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00025 | $0.00404 |
| Opus 5.5 | $0.00010 | $0.00162 |
| Sonnet 5.5 | $0.00005 | $0.00081 |
| Haiku 4.5 | $0.00003 | $0.00040 |
Grade A, and why
codex-crosscheck scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Codex cross-check
Description: Delegate the question to the codex-advisor subagent. It
fetches the Codex answer, verifies its claims against the code, and delivers a
synthesis against its own position.
Argument: $ARGUMENTS: the question. If it is missing, ask once, briefly.
Costs more than /codex: on top of the Codex quota it also spends Claude
tokens for the shell around it. If you only want the OpenAI answer, use /codex.
🚀 EXECUTION DIRECTIVE
Invoking this slash command IS the explicit user request. Start IMMEDIATELY, NO follow-up questions (unless the question itself is missing).
Procedure
-
Task the
codex-advisorsubagent with the question from$ARGUMENTS. Do not call the wrapper yourself; that would be/codex. -
Give the subagent the context it needs: which files are involved and what the decision is. It forms its own position from that before asking Codex.
-
Relay its synthesis. It contains four parts: the question asked, its own position, Codex's position with a note on what was verified, and the synthesis separating measured, inferred and open.
-
Do not smooth over disagreement between the models. The dissent is the result, not a flaw in it.
When this command is the right one
- Architecture decisions that would be expensive to reverse
- Root-cause analysis after two fixes have failed
- Security questions: authentication, cryptography, untrusted input
- Non-trivial algorithms with edge cases
Not for naming questions, style, or understanding code. And not when you simply want the OpenAI answer.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 49 lines · 25 tokens per session scan A fcd53b5a3ddb
codex-crosscheck is a command published in the GitHub repository fidpa/codex-sandbox-toolkit (1 stars, last pushed 1mo ago), licensed MIT. It adds 25 tokens to every session and 404 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other commands, from other repositories
review
Manage AO code reviews of a worker's PR.
pi-code-review
Adversarial code review via Codex — break confidence in changes, not validate them.
pi-fact-check
Fact-check content via Gemini search + Claude verification — cross-provider claim validation.
pi-askall
Ask both Codex and Gemini the same question — get three perspectives with Claude synthesis.
pi-ask-gemini
Ask Gemini a question — get Google's perspective alongside Claude's.
pr-review
Generate a PR review report aggregating quality scan, coverage, complexity, and breaking changes.