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 allemaar/open-skills --skill double-checkgit clone --depth 1 https://github.com/allemaar/open-skillsWrote 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/allemaar/open-skills/double-check)<a href="https://agentmods.dev/skills/allemaar/open-skills/double-check"><img src="https://agentmods.dev/badge/skills/allemaar/open-skills/double-check/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/allemaar/open-skills/double-check"><img src="https://agentmods.dev/badge/skills/allemaar/open-skills/double-check.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 | $0.00117 | $0.01141 |
| Opus 5 | $0.00059 | $0.00571 |
| Sonnet 5 | $0.00023 | $0.00228 |
| Haiku 4.5 | $0.00012 | $0.00114 |
Grade A, and why
double-check 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 11d 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 — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
/double-check
Multi-pass re-verification of a plan, output, decision, or document — re-read from scratch, challenge assumptions, propose improvements, and iterate until solid.
Re-Read & Improve Protocol — not a single-pass gate. The agent re-reads the target fresh, challenges each part, proposes improvements, and iterates. Each pass tightens the result.
Structured execution spec:
protocol.yon. It carries the five phases, the scope/verdict gates, and the rules as validatable records; this file is the explanation. Keep the two in sync — edit one, update the other and refresh the@STAMPdate.
Caller Options. Before executing, run the Caller Options protocol (
caller-options/SKILL.md): triage this invocation for material optionality across the venues and modes declared in front-matter; if one path clearly dominates, proceed silently; otherwise surface the options to the caller. A resolved-invocation marker means COP already ran — execute the fixed combination directly, do not re-enter COP.
Phase 1: Scope
Identify what is being double-checked — a plan, an output, a decision, a document. Load it fresh. Do not rely on prior context or cached understanding.
Gate: Cannot double-check without a clear target. If the target is ambiguous, ask before proceeding.
Phase 2: Fresh Re-Read
Re-read the target from scratch as if seeing it for the first time. Go back to the actual sources — files, code, docs. Do not verify from memory or prior analysis alone.
Summarize:
- What it says
- What it assumes (implicit and explicit)
- What it depends on
List every assumption, stated or unstated.
Phase 3: Challenge
Challenge each part of the target. Be adversarial — actively try to find problems.
For plans: Are any steps wrong, missing, out of order, or unnecessary? For outputs: Are any claims unsupported? For decisions: Were alternatives considered?
Look for:
- Gaps and omissions
- Wrong or unstated assumptions
- Over-engineering or under-engineering
- Scope issues
- Ordering issues
- Missing dependencies
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 11d ago First seen · 123 lines · 117 tokens per session scan A 66fed4b22491
double-check is a skill published in the GitHub repository allemaar/open-skills (14 stars, last pushed 24d ago), licensed Apache-2.0. It adds 117 tokens to every session and 1,141 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 2026-08-30.
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