Logprob Prefill Analysis

Q: What is a Claude Code skill and how does the Logprob Prefill Analysis skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Logprob Prefill Analysis is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Security category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Security · Sub-category: red-team · Last updated: 2026-05-21

Reproduces the full prefill sensitivity analysis pipeline for reward hacking indicators. Use when evaluating how susceptible model checkpoints are to exploit-eliciting prefills, computing token-based trajectories, or comparing logprob vs token-count as predictors of exploitability.

From the source SKILL.md

This skill documents the complete pipeline for measuring model susceptibility to reward hacking via prefill sensitivity analysis, including both token-based and logprob-based metrics.

What this skill does

Logprob Prefill Analysis is a community-contributed Claude Code skill in the red-team sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/logprob-prefill-analysis/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when evaluating how susceptible model checkpoints are to exploit-eliciting prefills, computing token-based trajectories, or comparing logprob vs token-count as predictors of exploitability.

Who uses this skill

The Logprob Prefill Analysis Claude Code skill is built for security engineers, penetration testers, DevSecOps practitioners, and development teams hardening codebases and infrastructure. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 116,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/logprob-prefill-analysis
curl -L https://claudskills.com/skills/logprob-prefill-analysis/SKILL.md \
  -o ~/.claude/skills/logprob-prefill-analysis/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/logprob-prefill-analysis/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/logprob-prefill-analysis/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\logprob-prefill-analysis\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Logprob Prefill Analysis Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/logprob-prefill-analysis/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Logprob Prefill Analysis skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Logprob Prefill Analysis skill?

Use Logprob Prefill Analysis when your Claude Code task falls under the Security category — specifically in the red team area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Logprob Prefill Analysis" or describe the task and let Claude pick). Browse related skills at /category/security/.

What is a Claude Code skill and how does the Logprob Prefill Analysis skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Logprob Prefill Analysis is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Security category. Learn more at /learn/what-is-a-claude-skill/.

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

ClaudSkills. (2026). Logprob Prefill Analysis [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/logprob-prefill-analysis/

BibTeX

@misc{logprob-prefill-analysis-2026,
  author    = {ClaudSkills},
  title     = {Logprob Prefill Analysis [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/logprob-prefill-analysis/}
}

Embed this skill

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Badge

[![ClaudSkills](https://claudskills.com/badge/logprob-prefill-analysis.svg)](https://claudskills.com/skills/logprob-prefill-analysis/?utm_source=badge&utm_medium=readme&utm_campaign=skill_badge)

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Part of ClaudSkills — the open registry for Claude Skills & Claude Code Skills. · What's New · Install guide · About · llms.txt

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