env-config

env-config is a skill for Claude Code from kazdenc/builder-skills. It costs 53 tokens per session (2,073 once invoked), scanned A, original, MIT.

A guide to environment variables, which store configuration such as service URLs and secrets outside application code, across development, testing, staging, and production.

In plain words
What is it for?
Use it to create environment files, define naming rules, document required variables, and configure settings for different environments.
Why use it?
It keeps environment-specific settings organized, validates them, documents them, and helps prevent secrets from being committed to version control.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it to create environment files, define naming rules, document required variables, and configure settings for different environments.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kazdenc/builder-skills/env-config
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 kazdenc/builder-skills --skill env-config
Clone the repo
git clone --depth 1 https://github.com/kazdenc/builder-skills

Made for: Claude Code.

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 env-config

README.md
[![agentmods](https://agentmods.dev/badge/skills/kazdenc/builder-skills/env-config/github.svg)](https://agentmods.dev/skills/kazdenc/builder-skills/env-config)
Your own site
<a href="https://agentmods.dev/skills/kazdenc/builder-skills/env-config"><img src="https://agentmods.dev/badge/skills/kazdenc/builder-skills/env-config/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 env-config

Your own site · 80×15
<a href="https://agentmods.dev/skills/kazdenc/builder-skills/env-config"><img src="https://agentmods.dev/badge/skills/kazdenc/builder-skills/env-config.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,073 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 $0.00053 $0.02073
Opus 5 $0.00026 $0.01037
Sonnet 5 $0.00011 $0.00415
Haiku 4.5 $0.00005 $0.00207

Measured 9d ago against content hash 97afd64b40a8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

env-config 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.

.claude/skills/dev/setup/env-config/SKILL.md · 247 lines

How it starts

The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Environment Variable Configuration

Set up environment variables with validation, documentation, and secure handling across environments. If target names a service (Supabase, Stripe, etc.), scope to that service's vars. Otherwise, set up the full env system.

Step 1: File Structure

Create these files in the project root:

File Purpose Committed to git?
.env.local Local development overrides. Highest priority. No
.env.development Defaults for next dev Yes (no secrets)
.env.production Defaults for next build Yes (no secrets)
.env.example Template documenting every variable Yes
.env.test Test environment overrides Yes (no secrets)

Load order (Next.js)

Next.js loads env files in this order (later files override earlier):

  1. .env (all environments)
  2. .env.local (all environments, git-ignored)
  3. .env.[environment] (e.g., .env.development)
  4. .env.[environment].local (e.g., .env.development.local, git-ignored)

Step 2: Naming Conventions

Rule Example Why
SCREAMING_SNAKE_CASE DATABASE_URL Standard convention
NEXT_PUBLIC_ prefix for client-side NEXT_PUBLIC_APP_URL Next.js exposes only prefixed vars to the browser
Group by service SUPABASE_URL, SUPABASE_ANON_KEY Easy to find related vars
No NEXT_PUBLIC_ for secrets STRIPE_SECRET_KEY (not NEXT_PUBLIC_STRIPE_SECRET_KEY) Never expose secrets to the client

Common variable groups

Service Variables Client-safe?
App NEXT_PUBLIC_APP_URL, NEXT_PUBLIC_APP_NAME Yes
Supabase NEXT_PUBLIC_SUPABASE_URL, NEXT_PUBLIC_SUPABASE_ANON_KEY, SUPABASE_SERVICE_ROLE_KEY URL and anon key: yes. Service role: no.
Stripe NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY, STRIPE_SECRET_KEY, STRIPE_WEBHOOK_SECRET Publishable: yes. Others: no.
Auth NEXTAUTH_SECRET, NEXTAUTH_URL No
Email RESEND_API_KEY, EMAIL_FROM No
Analytics NEXT_PUBLIC_POSTHOG_KEY, NEXT_PUBLIC_POSTHOG_HOST Yes

Read the full file on GitHub · 247 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. 9d ago First seen · 247 lines · 53 tokens per session scan A 97afd64b40a8

Subscribe to this mod's changes

env-config is a skill published in the GitHub repository kazdenc/builder-skills (45 stars, last pushed 6mo ago), licensed MIT. It adds 53 tokens to every session and 2,073 once invoked, about $0.0003 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 2026-08-30.

Related

Other skills, from other repositories

adapter-aws-lambda

Deploy tRPC on AWS Lambda with awsLambdaRequestHandler() from @trpc/server/adapters/aws-lambda for API Gateway v1 (REST, APIGatewayProxyEvent) and v2 (HTTP, APIGatewayProxyEventV2), and Lambda Function URLs. Enable response streaming with awsLambdaStreamingRequestHandler() wrapped in awslambda.streamifyResponse().…

trpc/trpc · 93 tokens

adapter-fetch

Deploy tRPC on WinterCG-compliant edge runtimes with fetchRequestHandler() from @trpc/server/adapters/fetch. Supports Cloudflare Workers, Deno Deploy, Vercel Edge Runtime, Astro, Remix, SolidStart. FetchCreateContextFnOptions provides req (Request) and resHeaders (Headers) for context creation. The endpoint option…

trpc/trpc · 86 tokens

trigger-cost-savings

Analyze Trigger.dev tasks, schedules, and runs for cost optimization opportunities. Use when asked to reduce spend, optimize costs, audit usage, right-size machines, or review task efficiency. Combines static source analysis with live run analysis via the Trigger.dev MCP tools (listruns, getrundetails…

triggerdotdev/trigger.dev · 68 tokens

portaljs-deploy

Deploy a PortalJS portal to PortalJS Arc — Datopian-managed static hosting on Cloudflare. Builds a static export, uploads it, and returns a live SLUG.arc.portaljs.com URL. One command, one target. Use when a portal is ready to publish or redeploy to a live URL.

datopian/portaljs · 66 tokens

prepare-cloudflare-production-deployment

Source-of-truth runbook for preparing this Vinext Cloudflare Workers SaaS template for production deployment. Use when setting up or auditing Cloudflare MCP resources, wrangler.jsonc bindings, Worker secrets, Turnstile, Email Sending, GitHub Actions secrets/variables, or GitHub CLI deployment wiring for this…

LubomirGeorgiev/cloudflare-workers-nextjs-saas-template · 72 tokens

deploy-release

Prepare and verify a staged or production deployment with rollback and smoke checks.

HoangNguyen0403/agent-skills-standard · 17 tokens