arnesto: Skill for Claude Code

.agents/skills/xp-predict-problems/SKILL.md

xp-predict-problems is a skill for Claude Code, Codex from saski/arnesto. It costs 36 tokens per session (177 once invoked), scanned A, original, Unlicense.

A guide for predicting where software is likely to fail in production. It examines edge cases, complex paths, weak tests, assumptions, and outside services.

In plain words
What is it for?
Use it to assess production risk, identify fragile parts of a codebase, examine external dependencies, and find reliability improvements.
Why use it?
It helps reveal likely failures before users encounter them and explains which situations could trigger each problem.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is saski/arnesto's own configuration. It tells Claude Code and Codex how to work on arnesto itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything arnesto configures →

Reuse

Borrowing it

Nothing to install: this file belongs to saski/arnesto. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/saski/arnesto/main/.agents/skills/xp-predict-problems/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/saski/arnesto

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 xp-predict-problems

README.md
[![agentmods](https://agentmods.dev/badge/skills/saski/arnesto/xp-predict-problems.svg)](https://agentmods.dev/skills/saski/arnesto/xp-predict-problems)
Your own site
<a href="https://agentmods.dev/skills/saski/arnesto/xp-predict-problems"><img src="https://agentmods.dev/badge/skills/saski/arnesto/xp-predict-problems.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 177 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.
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 $0.00036 $0.00177
Opus 5 $0.00018 $0.00088
Sonnet 5 $0.00007 $0.00035
Haiku 4.5 $0.00004 $0.00018

Measured 3d ago against content hash c46748a576a7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

xp-predict-problems 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 3d 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.

.agents/skills/xp-predict-problems/SKILL.md · 21 lines

What it actually says

Senior XP Developer — Predict Production Failures

Act as a Senior XP Developer with Lean thinking. Use small steps, clarity, and deep understanding of failure modes to improve reliability.

Task

Predict where the code is most likely to fail or cause issues in production. Focus on:

  • High-risk paths (edge cases, data assumptions, external dependencies).
  • Areas with high complexity, weak tests, or unclear intent.
  • Behavior that could degrade flow, performance, or correctness.

Briefly explain:

  • Why each predicted failure is plausible.
  • What production scenario could trigger it.
  • How addressing it improves simplicity and long-term evolvability.
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. 3d ago First seen · 21 lines · 36 tokens per session scan A c46748a576a7

Subscribe to this mod's changes

xp-predict-problems is a skill published in the GitHub repository saski/arnesto (5 stars, last pushed today), licensed Unlicense. It adds 36 tokens to every session and 177 once invoked, about $0.0002 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 2026-09-03.

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