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-initgit 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-init)<a href="https://agentmods.dev/skills/mathiasbourgoin/roster/arch-index-init"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/arch-index-init/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-init"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/arch-index-init.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 | $0.00033 | $0.00480 |
| Opus 5 | $0.00016 | $0.00240 |
| Sonnet 5 | $0.00007 | $0.00096 |
| Haiku 4.5 | $0.00003 | $0.00048 |
Grade A, and why
arch-index-init 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 today.
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-init
Builds (or refreshes) the project's arch-index database at .arch-index/index.db —
a SQLite call-graph + symbol index produced by the arch-index tool
(github.com/epure-team/arch-index). The gate (arch-index-gate) and audit
(arch-index-audit) skills only read this index; this skill is the sole writer.
Backend detection is automatic per detected language:
- LSP path — go, rust, typescript/javascript, python: the index is extracted through the language server (best-effort per upstream arch-index).
- CMT path — OCaml: the index is derived from
.cmttyped-AST artifacts under_build/(sound; requiresdune buildto have run first).
Steps
- Run
bash init.shfrom the project root (consumers invoke it via the seamentry). - The script detects project languages from manifest files (
go.mod,Cargo.toml,package.json/tsconfig.json,pyproject.toml/setup.py/requirements.txt,dune-project) and reports which backend applies. - If
.arch-index/index.dbalready exists it runsarch-index refresh, otherwisearch-index init. Exit 3 with a clear message when thearch-indexbinary is missing from PATH. - Add
.arch-index/to.gitignore— the index is a derived local artifact and must not be committed (the script reminds you in its output).
When to run
- Once after installing the pack, before the first roster-qa gate or audit run.
- After significant code changes, so gate/audit read a fresh index (the audit fragment discloses index staleness via its freshness header; it never regenerates the index itself).
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.
- today First seen · 43 lines · 33 tokens per session scan A 669656a89d3c
arch-index-init is a skill published in the GitHub repository mathiasbourgoin/roster (2 stars, last pushed yesterday), licensed MIT. It adds 33 tokens to every session and 480 once invoked, about $0.0002 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 2026-09-12.
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