adversarial-beam

adversarial-beam is a skill for Claude Code, Codex from pproenca/dot-skills. It costs 211 tokens per session (1,963 once invoked), scanned A, original, MIT.

A pass/fail review for Elixir systems running on the BEAM, the virtual machine behind Elixir and Erlang. It checks whether the design correctly handles supervision, failures, messages, shared state, and time.

In plain words
What is it for?
Use it to review Elixir features involving supervised processes, events, jobs, streams, PubSub broadcasts, ETS tables, or the Registry before merging.
Why use it?
It catches assumptions about runtime behaviour that can compile and pass tests but cause production failures. It gives a verdict based on evidence, but does not fix the code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; mentions Codex.

Good fit Use it to review Elixir features involving supervised processes, events, jobs, streams, PubSub broadcasts, ETS tables, or the Registry before merging.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pproenca/dot-skills/adversarial-beam
Install

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.

Any agent
npx skills add pproenca/dot-skills --skill adversarial-beam
Clone the repo
git clone --depth 1 https://github.com/pproenca/dot-skills

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for adversarial-beam

README.md
[![agentmods](https://agentmods.dev/badge/skills/pproenca/dot-skills/adversarial-beam.svg)](https://agentmods.dev/skills/pproenca/dot-skills/adversarial-beam)
Your own site
<a href="https://agentmods.dev/skills/pproenca/dot-skills/adversarial-beam"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/adversarial-beam.svg" alt="Measured on agentmods" height="20"></a>
Per session 211 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,963 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Anti-Refusal · line 51
    Skill instructs the agent to omit warnings, disclaimers, or ethical commentary. Stripping safety caveats hides risk from the user and is a common jailbreak preamble.
    Fix: Remove instructions that suppress warnings, disclaimers, or ethical commentary. Let the agent surface safety-relevant caveats to the user.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00211 $0.01963
Opus 5 $0.00105 $0.00981
Sonnet 5 $0.00042 $0.00393
Haiku 4.5 $0.00021 $0.00196

Measured 8d ago against content hash f0a29f1c2878, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

adversarial-beam 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 8d 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.

skills/.experimental/adversarial-beam/SKILL.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Adversarial BEAM Gate

A BEAM runtime-architecture review gate for Elixir systems — pass/fail: a single blind reviewer subagent judges the work against this gate's rules with an adversarial mandate, and the work passes only when every rule is PASS or N/A. This skill renders verdicts; it never fixes the work.

The rules target one failure mode: code that assumes guarantees the runtime never made — that restarts restore data, that mailboxes push back, that broadcasts arrive, that delivery happens exactly once and in order, that a lookup is still true at the following insert, that node-local uniqueness holds cluster-wide, that the wall clock only moves forward. These bugs compile cleanly, pass unit tests, and surface as production incidents. Each rule carries an Evidence of violation paragraph so a reviewer can decide PASS/FAIL/N/A from artifact evidence alone. The sibling gate adversarial-elixir judges paradigm fit (OO habits ported onto the BEAM); this gate judges runtime semantics — run both for full coverage.

When to Apply

  • An Elixir feature that supervises processes, consumes events/jobs/streams, broadcasts over PubSub, or shares state via ETS/Registry is about to merge and needs an objective PASS/FAIL on its runtime assumptions.
  • An agent (Claude, Codex) authored OTP-shaped code and you want an independent check that it did not assume durable broadcasts, exactly-once delivery, ordered cross-process messages, or restart-survivable in-memory state.
  • A system is being prepared for clustering or higher load, and the single-node/low-traffic assumptions baked into it need to be surfaced as verdicts.
  • An incident postmortem fixed one instance of a delivery/overload bug and you want the same class hunted across the affected area.

Do not apply to non-Elixir codebases (the reviewer prompt's precondition aborts with "GATE NOT APPLICABLE"), or when the user wants explanations and refactors rather than a verdict. The dist-* category goes N/A when the application demonstrably never clusters; Oban/Broadway appear in rules as canonical remedies but any mechanism with the same property passes — the reviewer prompt carries the applicability axes.

Read the full file on GitHub · 67 lines

Files

What ships with it

28 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.

Changes

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.

  1. 8d ago First seen · 67 lines · 211 tokens per session scan A f0a29f1c2878

Subscribe to this mod's changes

adversarial-beam is a skill published in the GitHub repository pproenca/dot-skills (203 stars, last pushed 23d ago), licensed MIT. It adds 211 tokens to every session and 1,963 once invoked, about $0.0011 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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