effect-development

effect-development is a skill for Claude Code, Codex from pingdotgg/t3code. It costs 21 tokens per session (140 once invoked), scanned A, original, MIT.

A set of repository-specific instructions for building or reviewing code with Effect, a TypeScript library for managing complex program behaviour. It tells you to find the project's local Effect documentation and follow its examples and conventions.

In plain words
What is it for?
It helps implement or review changes involving Effect APIs, concepts, and patterns, including checking nearby source code and tests for project conventions.
Why use it?
It reduces the risk of using the library's APIs or patterns incorrectly and prevents repository guidance from being missed. It also helps confirm when the available documentation does not cover a particular case.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

Good fit It helps implement or review changes involving Effect APIs, concepts, and patterns, including checking nearby source code and tests for project conventions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pingdotgg/t3code/effect-development
About the project

T3 Code is an app for controlling AI coding agents running on a user's computer through mobile, web, and desktop interfaces. Developers use it to work remotely with supported agents such as Codex, Claude Code, Cursor, Grok Build, OpenCode, and Antigravity. The catalogue add-ons support the T3 Code workflow.

pingdotgg/t3code · 27,790 stars · on GitHub · t3.codes

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 pingdotgg/t3code --skill effect-development
Clone the repo
git clone --depth 1 https://github.com/pingdotgg/t3code

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-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/pingdotgg/t3code/effect-development/github.svg)](https://agentmods.dev/skills/pingdotgg/t3code/effect-development)
Your own site
<a href="https://agentmods.dev/skills/pingdotgg/t3code/effect-development"><img src="https://agentmods.dev/badge/skills/pingdotgg/t3code/effect-development/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 effect-development

Your own site · 80×15
<a href="https://agentmods.dev/skills/pingdotgg/t3code/effect-development"><img src="https://agentmods.dev/badge/skills/pingdotgg/t3code/effect-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 140 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 $0.00021 $0.00140
Opus 5.5 $0.00008 $0.00056
Sonnet 5.5 $0.00004 $0.00028
Haiku 4.5 $0.00002 $0.00014

Measured 27d ago against content hash 2e674e3f30c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

effect-development 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 27d 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.

Origin

Copies of this mod

4 near-identical copies found in the catalogue:

.repos/effect-smol/.agents/skills/effect-development/SKILL.md · 17 lines

What it actually says

Use the repository's AI documentation as targeted reference, not ambient context:

  1. Identify the Effect APIs and concepts involved in the change.
  2. Search LLMS.md and ai-docs/src for those names and concepts, then read the matching sections and examples.
  3. Apply the relevant guidance and inspect nearby source and tests for any repository-internal conventions not covered by the documentation.

The task is ready for implementation when every material Effect API or pattern has matching local guidance, or the search has established that none exists.

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. 27d ago First seen · 17 lines · 21 tokens per session scan A 2e674e3f30c8

Subscribe to this mod's changes

effect-development is a skill published in the GitHub repository pingdotgg/t3code (27,790 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 140 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 2026-09-19.

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