experimenter

experimenter is a skill for Claude Code, Codex from rrpauls/hermes-esra. It costs 74 tokens per session (507 once invoked), scanned A, original, MIT.

A guide for testing proposed changes to skills, workflows, behavior, or decision methods through small, controlled experiments.

In plain words
What is it for?
Use it to form a testable hypothesis, design a limited experiment, set success measures, manage risks, and assess the findings.
Why use it?
It reduces the risk of adopting an improvement that does not work by defining what to test and how to judge the result.

Skill for Claude CodeCodex

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

Good fit Use it to form a testable hypothesis, design a limited experiment, set success measures, manage risks, and assess the findings.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rrpauls/hermes-esra/experimenter
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 rrpauls/hermes-esra --skill experimenter
Clone the repo
git clone --depth 1 https://github.com/rrpauls/hermes-esra

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 experimenter

README.md
[![agentmods](https://agentmods.dev/badge/skills/rrpauls/hermes-esra/experimenter/github.svg)](https://agentmods.dev/skills/rrpauls/hermes-esra/experimenter)
Your own site
<a href="https://agentmods.dev/skills/rrpauls/hermes-esra/experimenter"><img src="https://agentmods.dev/badge/skills/rrpauls/hermes-esra/experimenter/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 experimenter

Your own site · 80×15
<a href="https://agentmods.dev/skills/rrpauls/hermes-esra/experimenter"><img src="https://agentmods.dev/badge/skills/rrpauls/hermes-esra/experimenter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 507 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 $0.00074 $0.00507
Opus 5 $0.00037 $0.00253
Sonnet 5 $0.00015 $0.00101
Haiku 4.5 $0.00007 $0.00051

Measured 9d ago against content hash 6f97ec42e53f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

experimenter 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 9d 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.

skills/experimenter/SKILL.md · 57 lines

What it actually says

Experimenter

Role

You design and guide small, safe, hypothesis-driven experiments to test potential improvements in capabilities, workflows, or behavior. You help turn ideas for improvement into structured learning experiences.

When This Skill Activates

Use when there are proposed improvements that need testing before full adoption, or when exploring new approaches with controlled risk.

Core Process

  1. Formulate Clear Hypothesis
    Turn the proposed improvement into a testable statement.

  2. Value Alignment Assessment (with Value-Clarifier)

    • Explicitly assess how the proposed experiment aligns with core values and long-term direction.
    • Provide a short justification (1–3 sentences).
    • If there is significant misalignment, either adjust the experiment or clearly flag the conflict and reduce its priority.
  3. Design Minimal Experiment
    Create the smallest viable test with clear success criteria, timebox, and measurement.

  4. Assess Risk and Safeguards
    Identify downsides and add safety mechanisms (limited scope, rollback plan, monitoring).

  5. Run and Observe
    Execute while collecting relevant observations.

  6. Analyze Results
    Compare outcomes to the hypothesis and extract learnings.

  7. Decide Next Step
    Recommend: adopt, discard, modify, or run follow-up experiment.

Key Principles

  • Smaller and shorter experiments are preferred.
  • Experiments should be reasonably aligned with core values (Value Alignment Assessment is mandatory).
  • Learning is the primary goal.
  • Change one variable at a time when possible.
  • Always have an exit strategy.

Integration

  • Takes inputs from self-improver.
  • Performs mandatory Value Alignment Assessment with value-clarifier. Experiments with poor alignment receive lower priority.
  • Feeds learnings into mental-model-updater.
  • Useful when testing changes suggested by system-dynamics-thinker.

Output Style

Be practical and structured. Always include:

  • Hypothesis
  • Value Alignment justification
  • Experiment design, risks, success criteria
  • Expected learnings
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. 9d ago First seen · 57 lines · 74 tokens per session scan A 6f97ec42e53f

Subscribe to this mod's changes

experimenter is a skill published in the GitHub repository rrpauls/hermes-esra (2 stars, last pushed 1mo ago), licensed MIT. It adds 74 tokens to every session and 507 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 2026-08-31.