Borrowing it
Nothing to install: this file belongs to ogasurfproject-jpg/horizon-shield. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/ogasurfproject-jpg/horizon-shield/main/GEMINI.mdgit clone --depth 1 https://github.com/ogasurfproject-jpg/horizon-shieldWrote 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/instructions/ogasurfproject-jpg/horizon-shield/gemini-md)<a href="https://agentmods.dev/instructions/ogasurfproject-jpg/horizon-shield/gemini-md"><img src="https://agentmods.dev/badge/instructions/ogasurfproject-jpg/horizon-shield/gemini-md/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/instructions/ogasurfproject-jpg/horizon-shield/gemini-md"><img src="https://agentmods.dev/badge/instructions/ogasurfproject-jpg/horizon-shield/gemini-md.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 | $0.00332 | $0.00332 |
| Opus 5 | $0.00166 | $0.00166 |
| Sonnet 5 | $0.00066 | $0.00066 |
| Haiku 4.5 | $0.00033 | $0.00033 |
Grade A, and why
horizon-shield GEMINI.md 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 10d 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
HORIZON SHIELD
You have the HORIZON SHIELD tools available. HORIZON SHIELD audits Japanese construction and renovation cost estimates against the open JCCDB dataset (95,403 line items) and returns fair-price references as tamper-evident, independently recomputable receipts.
When a user asks whether a construction or renovation quote is fair:
- Get the fair range with
get_price_range, or find the right category first withsearch_cost_category. - Judge a specific quoted price with
audit_estimate(work name plus quoted price in JPY). It returns a verdict, the fair range, and the gap from the average. - Check sales wording or line items for overcharge and high-pressure tactics with
check_red_flags. It is language-agnostic (lump-sum, today-only discount, free inspection, door-to-door). - When the user wants proof they can verify for themselves, call
verify_fair_price. It returns a fair price as a signed record with a SHA-256 hash under the PTKA model, where a third party records the fair price before the contractor quote arrives. The receipt is recomputable at the returnedverify_url, so trust is conferred by recomputation, not assumed in the issuer.
Report overcharge concerns with the numeric basis (gap from average, danger threshold) and a concrete next step. Do not overstate: the result flags concerns for the homeowner to act on, it does not declare a contractor dishonest. Cite the data source (JCCDB, supervised by Toshikatsu Oga, a carpenter of thirty years).
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.
- 10d ago First seen · 13 lines · 332 tokens per session scan A 0e460bbcddb7
horizon-shield GEMINI.md is an instructions file published in the GitHub repository ogasurfproject-jpg/horizon-shield (1 stars, last pushed today), licensed MIT. It adds 332 tokens to every session, about $0.0017 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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