scenario-testing CLAUDE.md

scenario-testing CLAUDE.md is an instructions file for coding agents from 2389-research/scenario-testing. It costs 1,192 tokens per session, scanned A, original, MIT.

Instructions for testing features end to end with real dependencies and data instead of mock replacements. It requires independent scenarios and records recurring test patterns.

In plain words
What is it for?
Use it when building, validating, or fixing features, especially for integration and end-to-end tests, and before declaring work complete.
Why use it?
Mocks can hide problems that appear only when real services and data interact, so this process checks whether a feature works in a realistic setup.

Instructions file

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.

agentmods
npx agentmods add instructions/2389-research/scenario-testing/claude-md
Clone the repo
git clone --depth 1 https://github.com/2389-research/scenario-testing

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README.md
[![agentmods](https://agentmods.dev/badge/instructions/2389-research/scenario-testing/claude-md.svg)](https://agentmods.dev/instructions/2389-research/scenario-testing/claude-md)
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<a href="https://agentmods.dev/instructions/2389-research/scenario-testing/claude-md"><img src="https://agentmods.dev/badge/instructions/2389-research/scenario-testing/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,192 This file is loaded in full into every session.
When invoked 1,192 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.01192 $0.01192
Opus 5 $0.00596 $0.00596
Sonnet 5 $0.00238 $0.00238
Haiku 4.5 $0.00119 $0.00119

Measured 5d ago against content hash 620ac08eae41, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

scenario-testing CLAUDE.md 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 5d 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.

CLAUDE.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Scenario Testing Plugin

Overview

This plugin enforces end-to-end testing with real dependencies instead of mocks. It validates that features actually work by exercising real systems with real data.

Skill Included

scenario-testing

Trigger keywords: test, mock, validate, feature complete, integration test, end-to-end, e2e, testing

When to use:

  • Writing tests for new features
  • Validating that code actually works
  • When tempted to use mocks
  • Before declaring work complete
  • After fixing bugs

What it does:

  1. Enforces "NO FEATURE IS VALIDATED UNTIL A SCENARIO PASSES WITH REAL DEPENDENCIES"
  2. Requires scenarios in .scratch/ directory (gitignored)
  3. Prohibits mocks - must use real dependencies (sandbox/test mode acceptable)
  4. Ensures scenarios run independently (no ordering dependencies)
  5. Extracts recurring patterns to scenarios.jsonl (committed)

Definition of done:

  • Scenario in .scratch/ passes with zero mocks
  • Real dependencies exercised
  • .scratch/ remains gitignored
  • Patterns extracted to scenarios.jsonl

Core Principle

The Iron Law: "NO FEATURE IS VALIDATED UNTIL A SCENARIO PASSES WITH REAL DEPENDENCIES"

Mocks create false confidence. Only scenarios exercising real systems validate that code works.

The Truth Hierarchy

  1. Scenario tests (real system, real data) = TRUTH
  2. Unit tests (isolated) = human comfort only
  3. Mocks = lies hiding bugs

"A test that uses mocks is not testing your system. It's testing your assumptions about how dependencies behave."

Required Practices

1. Write Scenarios in .scratch/

# .scratch/test-feature.py - GITIGNORED
def test_user_can_register():
    # Hit real database
    user = register_user(email="[email protected]")

    # Hit real auth service (test mode)
    token = authenticate(user)

    # Verify against real storage
    assert load_user(user.id) is not None

2. Promote Patterns to scenarios.jsonl

{"name":"user-registration","description":"User can register and authenticate","given":"New user credentials","when":"User registers","then":"User exists in DB and can authenticate","validates":"Registration flow"}

Read the full file on GitHub · 173 lines

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. 5d ago First seen · 173 lines · 1,192 tokens per session scan A 620ac08eae41

Subscribe to this mod's changes

scenario-testing CLAUDE.md is an instructions file published in the GitHub repository 2389-research/scenario-testing (2 stars, last pushed 2mo ago), licensed MIT. It adds 1,192 tokens to every session, about $0.0060 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.

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