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 check-plain-envgit 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/check-plain-env)<a href="https://agentmods.dev/skills/plainlang/plain-forge/check-plain-env"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/check-plain-env/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/check-plain-env"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/check-plain-env.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 | $0.00120 | $0.06547 |
| Opus 5.5 | $0.00048 | $0.02619 |
| Sonnet 5.5 | $0.00024 | $0.01309 |
| Haiku 4.5 | $0.00012 | $0.00655 |
Grade D, and why
check-plain-env scanned grade D with 3 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 18d 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.
Asks for rootmediumPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
| Java | `brew install openjdk@21` then follow the post-install `sudo ln -sfn ...` step | Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
When emitting an install command, **match the host OS** detected in Step 1. Prefer the OS's first-party package manager. Don't suggest `curl | sh` style installs unless there is no alternative. Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
When emitting an install command, **match the host OS** detected in Step 1. Prefer the OS's first-party package manager. Don't suggest `curl | sh` style installs unless there is no alternative. How it starts
The opening of the file, as written. The whole thing — 288 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Check Plain Env
Always use the skill load-plain-reference to retrieve the ***plain syntax rules — but only if you haven't done so yet.
This skill answers one question: **does the host machine have everything the *plain project needs to render and test? It reads the project, derives the requirement list, probes the machine, and returns a report. It never installs anything itself — that decision belongs to the user.
When to run
- **First time you open a *plain project on a new machine — before the first render or
./test_scripts/run_unittests*.shinvocation. This is the most common case. - At the start of
forge-plainPhase 3 environment verification —forge-plainhistorically did this inline; delegate to this skill instead so the same check runs the same way everywhere. - After
add-feature— when the new feature brought in a new dependency (a new framework, a new service, a new package manager) the project didn't need before. - Before a real render — alongside
plain-healthcheck.plain-healthcheckanswers "are the specs renderable?"; this skill answers "can this machine render them?". Both should pass. - Onboarding — when a teammate (or CI runner, or fresh dev container) is about to start using the project.
- Debugging a confusing failure — when a test script exits with "command not found", "module not found", "could not connect", or similar before any test runs.
- On demand — whenever the user asks "what do I need to install for this project?".
This skill is read-only and observational. It does not edit .plain files, scripts, or configs, and it never invokes install commands on the user's behalf.
What this skill does NOT do
- It does not install anything. It only suggests install commands and lets the user run them.
- It does not generate scripts, modify
config.yaml, or change project files. Useimplement-*-testing-script,init-config-file, etc. for that. - It does not start services (databases, brokers, Docker daemons). It only checks whether the right binaries and (optionally) running endpoints are reachable.
- It does not validate the specs themselves (syntax, concepts, module graph). Use
plain-healthcheckfor that — the two skills are complementary. It only checks thatplain-parser, whichplain-healthcheckruns, is installed. - It does not print secrets. Check whether an env var is set (e.g.
printenv FOO >/dev/null && echo set || echo missing), never echo its value.
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.
- 18d ago Changed a310554b16e5
- 20d ago Changed · -1 lines scan F → D 7c942d04cfc6
- 1mo ago First seen · 289 lines · 120 tokens per session scan F 06ca6931e16c
check-plain-env is a skill published in the GitHub repository plainlang/plain-forge (79 stars, last pushed yesterday), licensed MIT. It adds 120 tokens to every session and 6,547 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it D with 3 findings (asks for root, downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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