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 agentmods add skills/ericrisco/rsc-harness/phoenixnpx skills add ericrisco/rsc-harness --skill phoenixgit 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/phoenix)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/phoenix"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/phoenix.svg" alt="Measured on agentmods" 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 | $0.00089 | $0.02881 |
| Opus 5 | $0.00044 | $0.01440 |
| Sonnet 5 | $0.00018 | $0.00576 |
| Haiku 4.5 | $0.00009 | $0.00288 |
Grade B, and why
phoenix scanned grade B 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 yesterday.
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.
Asks for rootmediumPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
Depth on defining and threading scopes, magic-link auth, sudo mode and query-level enforcement lives in `references/auth-and-scopes.md`. How it starts
The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Phoenix
You are building a web application on the BEAM with Phoenix. There is one mental model that keeps a Phoenix app coherent as it grows: contexts are the public API of your domain; the web layer (controllers, LiveViews, channels) is a thin caller of contexts. A LiveView that reaches into Repo directly, or a controller stuffed with business rules, is the first crack. Push logic down into a context function and the web layer stays a presentation shell you can swap (HTML → JSON → LiveView) without rewriting the domain.
Target the current stack: Phoenix 1.8.7 (1.8.0 shipped 2025-08-05), LiveView 1.1 (1.1.x patch line; 1.0 shipped 2024-12-03), Ecto as the data layer, Erlang/OTP 25+. The headline 1.8 change is scopes: generators thread the current actor (user/org) through every context function and into the query, so secure-by-default data access is the norm, not something you bolt on later. New apps ship daisyUI + Tailwind theming, a single root layout, and an AGENTS.md for LLM-assisted work.
If the question has no web, Ecto or LiveView in it — it is a GenServer, a supervision tree, a mix release — that is the runtime, route to ../elixir/SKILL.md.
Where does this code go — generator decision
Pick the layer first, then the generator. Getting this wrong means rewriting the boundary later.
| You are building | Use | Generator |
|---|---|---|
| Stateless page or JSON endpoint, request→response | Controller + view | mix phx.gen.html / phx.gen.json |
| Stateful interactive UI, server-rendered, live updates | LiveView | mix phx.gen.live |
| Raw bidirectional WebSocket / fan-out to many clients | Channel + PubSub | hand-wire, no generator |
| Domain logic with no UI yet (just the boundary) | Context only | mix phx.gen.context |
| Login, sessions, password reset, scopes | Auth scaffold | mix phx.gen.auth |
Rule: generate the context first, then the web layer on top of it. phx.gen.live and phx.gen.html already produce a context — don't hand-write a controller that calls Repo and skip the context.
What ships with it
6 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.
- yesterday First seen · 170 lines · 89 tokens per session scan B 283075ea53ea
phoenix is a skill published in the GitHub repository ericrisco/rsc-harness (64 stars, last pushed 2d ago), licensed MIT. It adds 89 tokens to every session and 2,881 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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