claude-codex-settings is a collection of configurations and reusable extensions for Claude Code, OpenAI Codex, Cursor, and related coding tools. Developers use its skills, commands, hooks, agents, plugins, and MCP servers to shape coding-agent workflows and connect alternative model APIs. The catalogue entries are components of this collection that can be installed into supported coding tools.
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.
npx skills add fcakyon/claude-codex-settings --skill sandbox-migrate-to-nextgit clone --depth 1 https://github.com/fcakyon/claude-codex-settingsWrote 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/skills/fcakyon/claude-codex-settings/sandbox-migrate-to-next)<a href="https://agentmods.dev/skills/fcakyon/claude-codex-settings/sandbox-migrate-to-next"><img src="https://agentmods.dev/badge/skills/fcakyon/claude-codex-settings/sandbox-migrate-to-next/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/skills/fcakyon/claude-codex-settings/sandbox-migrate-to-next"><img src="https://agentmods.dev/badge/skills/fcakyon/claude-codex-settings/sandbox-migrate-to-next.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 | $0.00045 | $0.01955 |
| Opus 5.5 | $0.00018 | $0.00782 |
| Sonnet 5.5 | $0.00009 | $0.00391 |
| Haiku 4.5 | $0.00005 | $0.00196 |
Grade A, and why
sandbox-migrate-to-next 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 17d 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.
This is a copy
97% identical to sandbox-migrate-to-next — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 187 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Migrate stable → Sandbox SDK 1.0 preview (@next)
Perform the port. Follow the steps in order. Depth lives in docs—fetch the linked page when a step needs detail.
Human guide: Migrate · 1.0 preview
New projects should start on @next (sandbox-next), not this skill. Day-to-day stable work → sandbox-stable. Deprecated-API cleanup without moving to @next → 2026 deprecation guide first if needed.
Existing apps should migrate when you can, so you are ready when 1.0 becomes the stable release. Do not force production cutover without the user agreeing.
Prefer installed @next types and the migrate doc over memory.
Workflow
- Review hard rules and the replacement map
- Audit the codebase; list hits and target shapes
- Clarify with the user (cutover, bridge, Python image, unclear sites)
- Upgrade package, image, and code
- Validate
Stop after any step that needs a user decision.
Hard rules
- Worker package and container image must be the same
@nextline. - Production cutover uses immediate container rollout. Stable and
@nextcontrol protocols are incompatible both ways; gradual rollout leaves a broken mixed window. In-flight container work can stop. - After cutover,
await sandbox.exec(...)means process started, not command finished. - Argv is as-is (no implicit shell). Shell syntax needs an explicit shell binary.
- Process handles have no stdin → terminals for interactive input.
- Observation
timeout/AbortSignalcancel the wait only, not the process. - No single retry loop for every error.
- Do not invent APIs (
gitCheckouton core, process stdin, string-exec completion helper). - Self-deployed bridge stays on stable (not part of the preview line yet).
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.
- 17d ago Changed c878aa542f9f
- 1mo ago First seen · 187 lines · 45 tokens per session scan A 9bee4ace26bb
sandbox-migrate-to-next is a skill published in the GitHub repository fcakyon/claude-codex-settings (1,181 stars, last pushed yesterday), licensed Apache-2.0. It adds 45 tokens to every session and 1,955 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 97% identical to sandbox-migrate-to-next, differing in 1 line, and is treated as a copy.
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