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 agentmods add rules/pauljphilp/effectpatterns/access-environment-variablesgit clone --depth 1 https://github.com/PaulJPhilp/EffectPatternsWhat 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 | $0.00542 | $0.00542 |
| Opus 5 | $0.00271 | $0.00271 |
| Sonnet 5 | $0.00108 | $0.00108 |
| Haiku 4.5 | $0.00054 | $0.00054 |
Grade A, and why
access-environment-variables 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.
description: Use Effect to access environment variables with proper error handling. globs: "**/*.ts" alwaysApply: true
Access Environment Variables
Rule: Use Effect to access environment variables with proper error handling.
Example
import { Effect, Config, Option } from "effect"
// ============================================
// BASIC: Read required variable
// ============================================
const getApiKey = Config.string("API_KEY")
const program1 = Effect.gen(function* () {
const apiKey = yield* getApiKey
yield* Effect.log(`API Key: ${apiKey.slice(0, 4)}...`)
})
// ============================================
// OPTIONAL: With default value
// ============================================
const getPort = Config.number("PORT").pipe(
Config.withDefault(3000)
)
const program2 = Effect.gen(function* () {
const port = yield* getPort
yield* Effect.log(`Server will run on port ${port}`)
})
// ============================================
// OPTIONAL: Return Option instead of failing
// ============================================
const getOptionalFeature = Config.string("FEATURE_FLAG").pipe(
Config.option
)
const program3 = Effect.gen(function* () {
const feature = yield* getOptionalFeature
if (Option.isSome(feature)) {
yield* Effect.log(`Feature enabled: ${feature.value}`)
} else {
yield* Effect.log("Feature flag not set")
}
})
// ============================================
// COMBINED: Multiple variables as config object
// ============================================
const AppConfig = Config.all({
apiKey: Config.string("API_KEY"),
apiUrl: Config.string("API_URL"),
port: Config.number("PORT").pipe(Config.withDefault(3000)),
debug: Config.boolean("DEBUG").pipe(Config.withDefault(false)),
})
const program4 = Effect.gen(function* () {
const config = yield* AppConfig
yield* Effect.log(`API URL: ${config.apiUrl}`)
yield* Effect.log(`Port: ${config.port}`)
yield* Effect.log(`Debug: ${config.debug}`)
})
// ============================================
// RUN: Will fail if required vars missing
// ============================================
Effect.runPromise(program4).catch((error) => {
console.error("Missing required environment variables")
console.error(error)
})
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.
- 2d ago First seen · 92 lines · 542 tokens per session scan A ec6b74cd9e66
access-environment-variables is a cursor rule published in the GitHub repository PaulJPhilp/EffectPatterns (794 stars, last pushed 2mo ago), licensed MIT. It adds 542 tokens to every session, about $0.0027 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.
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