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 | $0.00031 | $0.00508 |
| Opus 5 | $0.00015 | $0.00254 |
| Sonnet 5 | $0.00006 | $0.00102 |
| Haiku 4.5 | $0.00003 | $0.00051 |
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 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-gate
Deterministic invariant gate for roster-qa (GateExitContract, exits 0/1/2/3).
The consumer (scripts/code-intel-resolve.js gate) extracts the fenced
code-intel block from kb/properties.md and passes its path as $1; this
skill's gate.sh evaluates each declared invariant against the SQLite index at
.arch-index/index.db (built by arch-index-init — never rebuilt here).
Check contract (pack-owned check semantics)
Only "type": "reachability" invariants are supported — any other type is a
malformed declaration for this pack (exit 2, naming the unsupported type).
Each check object is:
{"query": "<SQL against the index>", "expect": "none"}
{"query": "<SQL against the index>", "max": 5}
Row-count semantics: expect: "none" → any returned row is a violation;
max: N → more than N rows is a violation. Queries run via
arch-index query --json when the binary is available, else directly via
sqlite3 .arch-index/index.db.
Steps
- roster-qa invokes
bash gate.sh <invariants.jsonl>from the project root. - Degradation checks first (exit 3, verdict-neutral): index DB absent; both
arch-indexandsqlite3missing; OCaml project (dune-projectpresent) with no*.cmtartifacts under_build/("cmt-artifacts-missing (run dune build)"). - Declarations parse (exit 2 on malformed JSON or unsupported check type — defense in depth; the resolver pre-validates the envelope).
- Each invariant's query runs; violations print the invariant id plus the offending rows, and the gate exits 1 after evaluating all invariants.
- All checks pass → one
PASS <id>line per invariant, exit 0 (zero declared invariants also exits 0).
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 · 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 today), licensed MIT. It adds 31 tokens to every session and 508 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.
Other skills, from other repositories
systematic-debugging
4-phase root cause debugging: understand bugs before fixing.
langsmith-observability
LLM observability platform for tracing, evaluation, and monitoring. Use when debugging LLM applications, evaluating model outputs against datasets, monitoring production systems, or building systematic testing pipelines for AI applications.
experimental-code-coverage-local-debugger
Runs code coverage locally via Universal Test Runner (UTR) or helper scripts, mimicking LUCI trybots. Activate when CQ tryjobs fail or underreport coverage, to test local GN/recipe repairs before uploading, or to debug hermetic crashes.
adversarial-reviewer
Adversarial code review that assumes bugs exist and hunts for them. Use when asked to review code, find bugs, audit for correctness, stress-test a PR, or when someone says "tear this apart" or "what's wrong with this". Give no benefit of the doubt — every line is guilty until proven innocent.
cli-e2e
Write, modify, or debug Docker-based Composio CLI end-to-end tests under ts/e2e-tests/cli, including binary invocation, fixture isolation, output assertions, and package manifests. Use for CLI E2E test suites only; use cli-command for CLI source implementation.
work
Deliver one maintainer-approved EmDash issue, choosing the bug-fix path for a defect and the direct implementation path for an enhancement or task.