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.
npx skills add plainlang/plain-forge --skill implement-prepare-environment-scriptgit clone --depth 1 https://github.com/plainlang/plain-forgeWrote 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.
[](https://agentmods.dev/skills/plainlang/plain-forge/implement-prepare-environment-script)<a href="https://agentmods.dev/skills/plainlang/plain-forge/implement-prepare-environment-script"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/implement-prepare-environment-script/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.
<a href="https://agentmods.dev/skills/plainlang/plain-forge/implement-prepare-environment-script"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/implement-prepare-environment-script.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00106 | $0.08784 |
| Opus 5.5 | $0.00042 | $0.03514 |
| Sonnet 5.5 | $0.00021 | $0.01757 |
| Haiku 4.5 | $0.00011 | $0.00878 |
Grade C, and why
implement-prepare-environment-script scanned grade C with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 20d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Recursive force deletehighDestructive command
rm -rf with a variable or a broad path is one typo away from removing the wrong tree.
3. **Working directory setup.** Define a working folder at `<temp>/<lang>_<basename>` — **identical** to the path the conformance script will use (`/tmp/<lang>_$(basename "$1")` in Bash, `Join-Path ([System.IO.Path]::Get How it starts
The opening of the file, as written. The whole thing — 248 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Implement Prepare Environment Script
This skill produces a single executable script that performs the one-time per-build setup that precedes a conformance-test run, following a consistent, language-agnostic pattern.
The reference implementation is assets/prepare_environment_java.sh and assets/prepare_environment_python.sh. Read it first — every script you produce must be a faithful translation of that pattern into the target language's tooling and the user's shell environment.
What a prepare-environment script is for
prepare_environment_<lang> is an optional sibling of run_conformance_tests_<lang>. It runs immediately before the conformance script and exists to:
- Stage the build into a working folder (the same one the conformance script will use).
- Pre-warm the dependency cache / build artifacts so the conformance script can start cold without re-downloading or re-compiling anything.
When this script exists for a project, the corresponding conformance script's own dependency-install phase degrades to "activate only" (see implement-conformance-testing-script/SKILL.md → "Skipping setup when prepare_environment exists"). When it doesn't exist, the conformance script does the setup inline.
Why this script exists at all (the structural reason)
The conformance test runner is invoked once per functional spec by the renderer — not once per render. Each functional spec in a module has its own plain_modules/<module>/tests/<spec>/ folder, and after the renderer finishes generating code for a new spec, it runs the conformance tests of every previous spec in the same module to detect regressions. For a module with N functional specs, the conformance script is invoked roughly N times on every render.
Without a prepare script, every one of those N invocations does the full dependency install (Python venv + pip install, full Maven dependency tree, npm ci, cargo build, ...) from scratch. That cost — paid N times per render — dominates the wall-clock time of rendering a non-trivial project.
What ships with it
2 files 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.
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.
- 20d ago Changed a5c7d34a8f49
- 1mo ago First seen · 248 lines · 106 tokens per session scan C 4a1cbbb054b3
implement-prepare-environment-script is a skill published in the GitHub repository plainlang/plain-forge (79 stars, last pushed yesterday), licensed MIT. It adds 106 tokens to every session and 8,784 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it C with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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