effect-platform-abstraction

effect-platform-abstraction is a skill for Claude Code, Codex from mpsuesser/pi-effect-harness. It costs 57 tokens per session (7,736 once invoked), scanned B, original, MIT.

A guide to using Effect's platform-independent services for files, processes, web requests, cryptography, and terminal input and output. Effect is a TypeScript library that lets shared code work with different runtime adapters.

In plain words
What is it for?
Writing portable filesystem, process, HTTP, cryptography, console, environment-variable, and command-line code with the platform implementation supplied at the edge.
Why use it?
It prevents application code from depending directly on Node.js, Bun, or browser APIs, so the same code can support multiple environments.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Writing portable filesystem, process, HTTP, cryptography, console, environment-variable, and command-line code with the platform implementation supplied at the edge.

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Install with agentmods
npx agentmods add skills/mpsuesser/pi-effect-harness/effect-platform-abstraction
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 mpsuesser/pi-effect-harness --skill effect-platform-abstraction
Clone the repo
git clone --depth 1 https://github.com/mpsuesser/pi-effect-harness

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.

agentmods badge for effect-platform-abstraction

README.md
[![agentmods](https://agentmods.dev/badge/skills/mpsuesser/pi-effect-harness/effect-platform-abstraction/github.svg)](https://agentmods.dev/skills/mpsuesser/pi-effect-harness/effect-platform-abstraction)
Your own site
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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 effect-platform-abstraction

Your own site · 80×15
<a href="https://agentmods.dev/skills/mpsuesser/pi-effect-harness/effect-platform-abstraction"><img src="https://agentmods.dev/badge/skills/mpsuesser/pi-effect-harness/effect-platform-abstraction.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,736 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 3 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 $0.00057 $0.07736
Opus 5 $0.00028 $0.03868
Sonnet 5 $0.00011 $0.01547
Haiku 4.5 $0.00006 $0.00774

Measured 8d ago against content hash c5a9eb73bf7c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade B, and why

effect-platform-abstraction scanned grade B 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 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

const response = await fetch('https://api.example.com/data', { method: 'POST',

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

const result = await axios.get('https://api.example.com/data');

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

**Anti-Pattern - Direct child_process:**
harnesses/effect/skills/effect-platform-abstraction/SKILL.md · 1,109 lines

How it starts

The opening of the file, as written. The whole thing — 1,109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Platform Abstraction with Effect

Effect Source Reference

The Effect v4 source is available at ~/.cache/effect-v4/. Browse and read files there directly to look up APIs, types, and implementations.

Reference this for:

  • FileSystem source: packages/effect/src/FileSystem.ts
  • Path source: packages/effect/src/Path.ts
  • Crypto source: packages/effect/src/Crypto.ts
  • Socket source: packages/effect/src/unstable/socket/
  • Platform layers: packages/platform-node/, packages/platform-bun/, and packages/platform-browser/
  • Migration guide: MIGRATION.md
  • Effect source: packages/effect/src/

Overview

Effect provides platform-independent abstractions with Node.js and Bun adapters, plus browser adapters for supported services such as HTTP and Crypto. Instead of using runtime-specific APIs directly, you write code once using Effect Platform services and provide the appropriate layer at the edge.

When to use this skill:

  • Writing file system operations
  • Spawning child processes or executing commands
  • Making HTTP requests
  • Generating cryptographic random bytes, UUIDs, or digests
  • Reading CLI arguments or environment variables
  • Performing console/terminal I/O
  • Working with paths across different operating systems
  • Building cross-platform applications or libraries

Why Effect Platform?

1. Cross-Platform Compatibility

Write once, run anywhere:

import { Effect, FileSystem } from 'effect';

// Works on Node.js and Bun
const readConfig = Effect.gen(function* () {
	const fs = yield* FileSystem.FileSystem;
	return yield* fs.readFileString('config.json');
});

2. Type-Safe Error Handling

All operations track errors in the Effect type signature:

import { Effect, FileSystem } from 'effect';

// Effect<string, PlatformError, FileSystem>
//        ↓           ↓              ↓
//                                   Required service
//                     Typed error channel
//          Success value

3. Resource Safety

Read the full file on GitHub · 1,109 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. 8d ago First seen · 1,109 lines · 57 tokens per session scan B c5a9eb73bf7c

Subscribe to this mod's changes

effect-platform-abstraction is a skill published in the GitHub repository mpsuesser/pi-effect-harness (24 stars, last pushed 2mo ago), licensed MIT. It adds 57 tokens to every session and 7,736 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 3 findings (sends data to an external url, makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.