prompt-regression

prompt-regression is a skill for Claude Code, Codex from agentscope-ai/OpenJudge. It costs 86 tokens per session (2,733 once invoked), scanned A, original, Apache-2.0.

A method for comparing an original prompt with a changed prompt on the same tasks. A prompt is the instruction given to a language model or agent.

In plain words
What is it for?
Running head-to-head prompt tests, selecting scoring dimensions, correcting for which prompt appears first, and reporting win rates with confidence intervals.
Why use it?
It shows whether a prompt change actually improves results instead of relying on a few examples or personal judgment.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Running head-to-head prompt tests, selecting scoring dimensions, correcting for which prompt appears first, and reporting win rates with confidence intervals.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/agentscope-ai/openjudge/06-prompt-regression
Install

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.

Any agent
npx skills add agentscope-ai/OpenJudge --skill 06-prompt-regression
Clone the repo
git clone --depth 1 https://github.com/agentscope-ai/OpenJudge

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 prompt-regression

README.md
[![agentmods](https://agentmods.dev/badge/skills/agentscope-ai/openjudge/06-prompt-regression/github.svg)](https://agentmods.dev/skills/agentscope-ai/openjudge/06-prompt-regression)
Your own site
<a href="https://agentmods.dev/skills/agentscope-ai/openjudge/06-prompt-regression"><img src="https://agentmods.dev/badge/skills/agentscope-ai/openjudge/06-prompt-regression/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.

agentmods 80×15 button for prompt-regression

Your own site · 80×15
<a href="https://agentmods.dev/skills/agentscope-ai/openjudge/06-prompt-regression"><img src="https://agentmods.dev/badge/skills/agentscope-ai/openjudge/06-prompt-regression.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,733 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 32
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
How audits are shown
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 $0.00086 $0.02733
Opus 5 $0.00043 $0.01367
Sonnet 5 $0.00017 $0.00547
Haiku 4.5 $0.00009 $0.00273

Measured 11d ago against content hash beb1e5d32139, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

prompt-regression 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 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/pairwise.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/eval_pipeline/06-prompt-regression/SKILL.md · 282 lines

How it starts

The opening of the file, as written. The whole thing — 282 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Regression

Compare two prompts head-to-head and determine, with statistical rigor, whether the candidate is better, worse, or tied on each evaluation dimension.

When to Activate

  • You changed the system prompt and want to verify it's actually better
  • You're iterating on RAG answer templates
  • You're optimizing agent step-by-step instructions
  • You want data to support a prompt change decision

Checklist

You MUST create a task for each item and complete them in order:

  1. Load and analyze prompts — diff the baseline vs candidate
  2. Derive comparison dimensions — from the prompt changes + task type
  3. Select graders per dimension — pairwise, judge, or rule
  4. Run position-debiased comparison — swap-aggregate to eliminate order bias
  5. Compute statistics — win rates + bootstrap 95% CI per dimension
  6. Present results — per-dimension verdict with confidence intervals

Fast path: run the bundled script

Don't hand-write the win-rate + bootstrap math (the swap-aggregation and CI are easy to get wrong). Run the bundled, tested script (scripts/pairwise.py, standard library only, no OpenJudge dependency):

python scripts/pairwise.py --comparisons comparisons.jsonl --candidate candidate --baseline baseline

Each comparison row: {"id","model_a","model_b","score","dimension"?} where score >= 0.5 means model_a won. Emit two rows per query with A/B swapped to debias position. The script reports per-dimension candidate/baseline/tie rates, bootstrap 95% CI, and a verdict (BETTER / WORSE / TIED / INSUFFICIENT_EVIDENCE / INCONCLUSIVE; exit 0 only if better). --self-test to verify it.

Steps below explain how to derive dimensions and produce the comparisons (with OpenJudge or any judge); the inline snippets are the reference behind the script.

Read the full file on GitHub · 282 lines

Files

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.

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. 11d ago First seen · 282 lines · 86 tokens per session scan A beb1e5d32139

Subscribe to this mod's changes

prompt-regression is a skill published in the GitHub repository agentscope-ai/OpenJudge (826 stars, last pushed 3d ago), licensed Apache-2.0. It adds 86 tokens to every session and 2,733 once invoked, about $0.0004 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 2026-08-30.

Related

Other skills, from other repositories

llm-as-judge-evaluation

Evaluate LLM outputs using frontier models as judges. Use for pairwise model comparison, quality scoring with custom rubrics, and automated evaluation pipelines. Covers position bias mitigation, statistical significance, and generating preference data for DPO/RLHF.

synthetic-sciences/openscience · 56 tokens

prompt-evaluation-runner

Use when evaluating prompts, LLM outputs, red-team suites, or model behavior with local eval configs and safe provider/cost controls.

yeaight7/agent-powerups · 33 tokens

ai-hacker

Use when aI and LLM security testing — prompt injection, model manipulation, data exfiltration via AI. Use when testing AI-powered applications, finding prompt injection vulnerabilities, or assessing LLM-integrated systems.

oyi77/1ai-skills · 47 tokens

llm-tester

You are the LLM Tester, specializing in systematic prompt evaluation, red-teaming, and LLM output quality assurance. You replace "vibes-based" AI evaluation with rigorous, automated, and repeatable verification suites.

buiphucminhtam/forgewright · 49 tokens

promptfoo-evaluation

Configure and run Promptfoo evaluations, assertions, rubrics, and datasets when testing LLM prompts or comparing model behavior.

seaworld008/Commonly-used-high-value-skills · 29 tokens

ai-engineering-toolkit

6 production-ready AI engineering workflows: prompt evaluation (8-dimension scoring), context budget planning, RAG pipeline design, agent security audit (65-point checklist), eval harness building, and product sense coaching.

sickn33/agentic-awesome-skills · 47 tokens