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 agentmods add skills/contains-studio/fable-delegator/use-codexnpx skills add contains-studio/fable-delegator --skill use-codexgit clone --depth 1 https://github.com/contains-studio/fable-delegatorWrote 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/contains-studio/fable-delegator/use-codex)<a href="https://agentmods.dev/skills/contains-studio/fable-delegator/use-codex"><img src="https://agentmods.dev/badge/skills/contains-studio/fable-delegator/use-codex.svg" alt="Measured on agentmods" 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 | $0.00110 | $0.03259 |
| Opus 5 | $0.00055 | $0.01630 |
| Sonnet 5 | $0.00022 | $0.00652 |
| Haiku 4.5 | $0.00011 | $0.00326 |
Grade A, and why
use-codex 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 225 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codex Subagent Skill
Spawn autonomous Codex CLI subagents to offload context-heavy work. Subagents burn their own tokens and return only their final message, so the parent's context stays clean.
Golden Rule: If task + intermediate work would add 3,000+ tokens to parent context → use a subagent.
Instructions
When invoking this skill:
- Clarify intent. Figure out what the user wants. If unclear, ask. Inline args ("use codex to review my auth plan") usually carry the intent — infer from them. Common buckets: second-opinion code review, refactor, plan validation, implementation of features, fresh perspective on a stuck bug, parallel comparison of approaches.
- Pick model + reasoning by task complexity (see Model + Reasoning Selection). Default:
gpt-5.6-terraathigh. - Preflight before fan-out. Before launching multiple agents, confirm codex is authenticated and not rate-limited: run
codex login status(or one cheap low-effort probe) first. Hitting a 401 or rate limit five agents into a fan-out wastes every agent already launched. - Spawn the subagent using the canonical invocation (Basic Usage). Pipe long prompts via stdin. For anything expected to run more than a minute — or any fan-out — run it in the background (see Background Fan-Out) so the parent keeps working.
- Act autonomously while it runs. Don't ask for permission mid-flight; the parent only sees the final result, so mid-task pauses waste tokens. Pause only for genuinely destructive operations (data loss, external impact, security).
- Monitor, don't fire-and-forget. Check completion, retry on failure, answer follow-ups if blocked. Feel free to run multiple sequential or parallel codex subagents.
- Verify independently — mandatory. Codex reporting success is a claim, not a result (see Verification). Never relay its summary as verified fact, and never dispatch dependent work on top of an unverified result.
- Present results, don't dump them. Summarize what Codex said in your own words, surface concrete code changes or recommendations, and leave the next move to the user. Subagent output is input for your synthesis. Keep your response to the user concise and specific.
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.
- 5d ago First seen · 225 lines · 110 tokens per session scan A 292e853ef6ac
use-codex is a skill published in the GitHub repository contains-studio/fable-delegator (10 stars, last pushed 1mo ago), licensed MIT. It adds 110 tokens to every session and 3,259 once invoked, about $0.0006 per session on Opus 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.
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