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 ericrisco/rsc-harness --skill elixirgit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/elixir)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/elixir"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/elixir/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/ericrisco/rsc-harness/elixir"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/elixir.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, 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 Memory Poisoning · line 11 Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
- high Memory Poisoning · line 203 Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
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 | $0.00072 | $0.02958 |
| Opus 5.5 | $0.00029 | $0.01183 |
| Sonnet 5.5 | $0.00014 | $0.00592 |
| Haiku 4.5 | $0.00007 | $0.00296 |
Grade A, and why
elixir scanned grade A with 1 finding 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 1mo 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
def fetch(id) do How it starts
The opening of the file, as written. The whole thing — 210 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Elixir
You are writing Elixir on the BEAM. The runtime gives you cheap isolated processes, preemptive scheduling, and supervision. The single mental shift that separates idiomatic Elixir from ported imperative code: let it crash and supervise it, do not defend every call. A process that hits an impossible state should die and be restarted clean by its supervisor — that is more correct than a try/rescue that limps on with corrupt state.
Default to pure functions. Most of your code is data transformation and needs no process at all. Reach for a process only when you need state, concurrency, or fault isolation. Target Elixir v1.19.5 (stable, requires Erlang/OTP 28.1+) or v1.20-rc (full type inference, OTP 27+/29). Use the modern stdlib: built-in JSON, set-theoretic type warnings, mix format.
Decision: do you even need a process?
A process is not "an object": spawning one to hold a value you could pass as an argument is the most common beginner mistake, and it adds a serialization bottleneck and a failure mode for nothing.
| Situation | Use | Why |
|---|---|---|
| Pure transform of input -> output | plain function / module | No state, no concurrency: a process only adds overhead and a mailbox |
| Hold mutable state behind an API | GenServer (or Agent for trivial state) |
Serializes access, owns a lifecycle, supervisable |
| Run N independent jobs concurrently | Task.async_stream / Task.Supervisor |
Bounded fan-out, results collected, crashes isolated |
| Isolate a risky/external boundary | a supervised process | A crash there restarts clean without taking down callers |
| Shared read-heavy cache | :ets table |
Concurrent lock-free reads, no single-process bottleneck |
Rule: if two pieces of code never run at the same time and share no mutable state, they are functions, not processes.
The functional core
Match in function heads, not with if — branches become exhaustive and self-documenting, and a non-match crashes loudly instead of silently falling through.
What ships with it
5 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.
- 1mo ago First seen · 210 lines · 72 tokens per session scan A dc450a0b3d4d
elixir is a skill published in the GitHub repository ericrisco/rsc-harness (231 stars, last pushed yesterday), licensed MIT. It adds 72 tokens to every session and 2,958 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
Other skills, from other repositories
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tui-design
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clack
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koko
Develop and extend Koko — the Elixir/OTP agent living alongside joelclaw. Covers OTP patterns, Redis bridge protocol, shadow execution, and workload implementation.