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 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/perf)<a href="https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/perf"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/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/perf"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/perf.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00050 | $0.01014 |
| Opus 5.5 | $0.00020 | $0.00406 |
| Sonnet 5.5 | $0.00010 | $0.00203 |
| Haiku 4.5 | $0.00005 | $0.00101 |
Grade A, and why
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 23d 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- elixir-phoenix-perf — 95% identical, 32 lines differ
- phx-perf — 94% identical, 26 lines differ
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.
- 23d ago Changed · -3 tokens per session b7d1d0dd7224
- 1mo ago Changed · +10 tokens per session 4115690d9676
- 1mo ago First seen · 125 lines · 43 tokens per session scan A 479222c3b1de
perf is a skill published in the GitHub repository oliver-kriska/claude-elixir-phoenix (569 stars, last pushed yesterday), licensed MIT. It adds 50 tokens to every session and 1,014 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-03.
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