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 mathiasbourgoin/roster --skill arch-index-gategit clone --depth 1 https://github.com/mathiasbourgoin/rosterWrote 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/mathiasbourgoin/roster/arch-index-gate)<a href="https://agentmods.dev/skills/mathiasbourgoin/roster/arch-index-gate"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/arch-index-gate/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/mathiasbourgoin/roster/arch-index-gate"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/arch-index-gate.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 | $0.00019 | $0.00303 |
| Opus 5.5 | $0.00008 | $0.00121 |
| Sonnet 5.5 | $0.00004 | $0.00061 |
| Haiku 4.5 | $0.00002 | $0.00030 |
Grade A, and why
arch-index-gate 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 27d 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
arch-index-gate
Run bash gate.sh <invariants.jsonl> from the project root. The script accepts
the existing reachability declaration envelope but returns exit 3 for every
nonempty block. SQL row counts do not prove negative reachability: an empty
result may mean an incomplete producer, an unresolved MAY_TOP edge, or an
unindexed source. Exit 0 is reserved for an empty block; malformed JSON or an
unsupported declaration type exits 2. No reachability verdict is emitted.
The index preflight requires arch-index's versioned main-schema OCaml CMT
producer, callgraph_contract=v1, sound_with_top provenance on every function
and edge, and valid edge kinds. A heuristic LSP database exits 3. A future gate
needs a typed reachability contract and a producer-completeness witness before
it may emit PASS for a negative claim. See
https://gitlab.com/nomadic-labs/ai-harness/arch-index/-/work_items/1 and
https://gitlab.com/nomadic-labs/ai-harness/arch-index/-/work_items/2.
What ships with it
2 files 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.
- 27d ago Changed · -20 lines · -12 tokens per session 45e9d3e5217b
- 1mo ago First seen · 47 lines · 31 tokens per session scan A ef062ea4d872
arch-index-gate is a skill published in the GitHub repository mathiasbourgoin/roster (2 stars, last pushed 6d ago), licensed MIT. It adds 19 tokens to every session and 303 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 2026-09-12.
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