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 oliver-kriska/claude-elixir-phoenix --skill phx-perfgit clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenixWrote 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/oliver-kriska/claude-elixir-phoenix/phx-perf)<a href="https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/phx-perf"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/phx-perf/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/oliver-kriska/claude-elixir-phoenix/phx-perf"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/phx-perf.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 | $0.00046 | $0.00976 |
| Opus 5 | $0.00023 | $0.00488 |
| Sonnet 5 | $0.00009 | $0.00195 |
| Haiku 4.5 | $0.00005 | $0.00098 |
Grade A, and why
phx-perf 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 6d 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.
This is a copy
94% identical to perf — 26 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Performance Analysis
Analyze code for performance issues across Ecto, LiveView, and OTP layers. Prioritize findings by impact and effort.
Usage
phx-perf # Analyze full project
phx-perf lib/my_app/accounts.ex # Analyze specific module
phx-perf --focus ecto # Ecto queries only
phx-perf --focus liveview # LiveView memory only
phx-perf --focus otp # OTP bottlenecks only
Arguments
$ARGUMENTS = Optional module/context path and --focus flag.
Iron Laws
- MEASURE BEFORE OPTIMIZING — Never optimize without evidence of a problem
- DATABASE FIRST — 90% of Elixir performance issues are query-related
- ONE CHANGE AT A TIME — Isolate optimizations to measure impact
- NEVER benchmark in dev mode — Always use
MIX_ENV=prodfor performance measurements; dev mode includes code reloading, debug logging, and unoptimized compilation that invalidate results
Workflow
Step 1: Identify Scope
Check specific file if provided. Otherwise scan full project:
# Find hot paths: contexts, LiveViews, workers
find lib/ -name "*.ex" | head -50
Step 2: Run Analysis Tracks
Spawn analysis agents in parallel based on focus:
Ecto Track (default or --focus ecto):
Spawn phx:elixir-reviewer with prompt:
"Analyze for N+1 queries, missing preloads, unindexed queries,
and inefficient patterns. Check: Repo.all in loops,
Enum.map with Repo calls, missing preload, queries without
indexes on WHERE/JOIN columns."
LiveView Track (default or --focus liveview):
Spawn phx:elixir-reviewer with prompt:
"Analyze LiveViews for memory issues: large assigns, missing
streams for lists, assigns that grow unbounded, heavy
handle_info processing, missing assign_async for slow ops."
OTP Track (only with --focus otp):
Spawn phx:otp-advisor with prompt:
"Analyze for OTP bottlenecks: GenServer mailbox growth,
synchronous calls in hot paths, missing Task.async for
parallel work, ETS opportunities for read-heavy state."
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.
- 6d ago First seen · 125 lines · 46 tokens per session scan A f3ccaf004644
phx-perf is a skill published in the GitHub repository oliver-kriska/claude-elixir-phoenix (541 stars, last pushed 4d ago), licensed MIT. It adds 46 tokens to every session and 976 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to perf, differing in 26 lines, and is treated as a copy.
Other skills, from other repositories
craftcms
Craft CMS 5 plugin and module development — extending Craft with PHP. Covers elements, element queries, services, models, records, controllers, migrations, queue jobs, console commands, field types, native fields, events, behaviors, Twig extensions, widgets, filesystems, permissions, project config, GraphQL, testing…
craft-php-guidelines
Craft CMS 5 PHP coding standards and conventions. ALWAYS load when writing, editing, reviewing, or discussing any PHP in a Craft plugin or module — even small edits. Also when running ECS, PHPStan, or scaffolding with ddev craft make. Covers: PHPDoc blocks (@author, @since, @throws chains), section headers…
craft-pest
Testing Craft CMS 5 plugins and modules with Pest — test isolation, database safety, and the markhuot/craft-pest-core harness. ALWAYS load when writing, running, fixing, or reviewing tests for a Craft plugin or module, and whenever a suite touches a real Craft install. Covers why rollback is opt-in, tests/Pest.php +…
milp-modeling-gurobi
When the user wants to build, solve, and debug mixed-integer linear programs in Python with Gurobi — creating variables, writing constraint-builder functions, setting objectives and parameters, handling solver status, and extracting solutions safely. Also use when the user mentions "gurobipy," "build a MIP model,"…
numpy-vectorization-for-optimization
When the user wants to remove slow Python loops from metaheuristic or optimization code using NumPy — population-level operations, batch fitness evaluation, distance matrices, broadcasting, argsort/argpartition idioms, defaultrng, and memory layout. Also use when the user mentions "vectorize," "numpy broadcasting,"…
odoo-js
Use when writing, reviewing, or migrating any JavaScript, OWL component, QWeb/OWL template, or SCSS under static/src in an Odoo module — POS overrides, backend widgets, website/public widgets, services. Carries PSAE review-derived principles for OWL correctness, the patch() discipline, template conventions, frontend…