A checklist for adding a new NEXTPUBLIC runtime environment variable. Environment variables are configuration values supplied to an application when it runs.

Use it when introducing a new NEXTPUBLIC environment variable to the application.

It helps ensure a new runtime setting is added consistently and does not miss required implementation steps. The description does not specify the individual steps.

How blockscout/frontend configures Claude Code and Codex

Reuse

Borrowing it

Nothing to install: this file belongs to blockscout/frontend. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/blockscout/frontend/main/.agents/skills/add-env-var/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/blockscout/frontend

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/blockscout/frontend/add-env-var/github.svg)](https://agentmods.dev/skills/blockscout/frontend/add-env-var)

Your own site

<a href="https://agentmods.dev/skills/blockscout/frontend/add-env-var"><img src="https://agentmods.dev/badge/skills/blockscout/frontend/add-env-var/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/blockscout/frontend/add-env-var"><img src="https://agentmods.dev/badge/skills/blockscout/frontend/add-env-var.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,591 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 unknown 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.

Model	Per session	Once invoked
Fable 5.1	$0.00027	$0.01591
Opus 5.5	$0.00011	$0.00636
Sonnet 5.5	$0.00005	$0.00318
Haiku 4.5	$0.00003	$0.00159

Measured 8d ago against content hash c94cd1665303, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

add-env-var 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 8d 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.

.agents/skills/add-env-var/SKILL.md · 173 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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.

8d ago Changed · +1 lines c94cd1665303
1mo ago Changed bb3effe91cba
1mo ago Changed · +1 lines ce33ff7e6d51
2mo ago First seen · 171 lines · 27 tokens per session scan A 711b9c3b080c

Subscribe to this mod's changes

add-env-var is a skill published in the GitHub repository blockscout/frontend (310 stars, last pushed yesterday), with no licence file. It adds 27 tokens to every session and 1,591 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-03.

DevOps and cloud blockchain ethereum explorer

add-env-var next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
add-env-varblockscout/frontend	Skill	310	yesterday	none	A	27	Claude Code, Codex
analyzing-ethereum-smart-contract-vulnerabilitiesmukul975/Anthropic-Cybersecurity-Skills	Skill	36k	2mo ago	Apache-2.0	A	49	Claude Code
foundry-testingPaulRBerg/foundry-template	Skill	642	7d ago	MIT	A	64	Codex
analyzing-ethereum-smart-contract-vulnerabilitiesxalgorix/xalgorix	Skill	1.3k	yesterday	Apache-2.0	A	49	Claude Code, Codex
blockchain-ethereumj4flmao/agent-skills	Skill	38	3d ago	MIT	A	242	Claude Code, Codex
lineth-quickstartLFDT-Lineth/lineth-monorepo	Skill	127	today	Apache-2.0	A	228	Claude Code, Codex
blockchain-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	63	Claude Code

frontend: Skill for Claude Code