Borrowing it
Nothing to install: this file belongs to mepuka/effect-ontology. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mepuka/effect-ontology/main/.claude/skills/effect-index/SKILL.mdgit clone --depth 1 https://github.com/mepuka/effect-ontologyWrote 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.
[](https://agentmods.dev/skills/mepuka/effect-ontology/effect-index)<a href="https://agentmods.dev/skills/mepuka/effect-ontology/effect-index"><img src="https://agentmods.dev/badge/skills/mepuka/effect-ontology/effect-index/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.
<a href="https://agentmods.dev/skills/mepuka/effect-ontology/effect-index"><img src="https://agentmods.dev/badge/skills/mepuka/effect-ontology/effect-index.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00024 | $0.01254 |
| Opus 5.5 | $0.00010 | $0.00502 |
| Sonnet 5.5 | $0.00005 | $0.00251 |
| Haiku 4.5 | $0.00002 | $0.00125 |
Grade A, and why
effect-index 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 2mo 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 — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Effect Skill Index
Use this as a quick router to the right Skill for your task. Each entry links to a focused Skill optimized for a coding agent’s limited context.
Decision Tree
- I need to write or refactor some Effect code → Foundations
- I need robust error handling/retries → Errors & Retries
- I must run things in parallel / manage fibers → Concurrency & Fibers
- This is a data pipeline / batching / backpressure → Streams & Pipelines
- I need DI/services/layers or test/live wiring → Layers & Services
- Opening files/sockets/servers with cleanup → Resources & Scope
- Add HTTP endpoints / JSON responses → HTTP & Routing
- Validate inputs / parse config → Config & Schema
- Value-based equality / high-perf immutable collections → Data Structures
- Time, logging, spans/tracing → Time/Tracing/Logging
- Queues, PubSub, background workers → Queues & Background
- Write tests/mocks for services → Testing & Mocking
- Looking for specific patterns or examples → Patterns Hub (130+ patterns)
Cross-Skill Patterns
All patterns are now available locally in the Patterns Hub (130+ patterns):
- Retry transient failures → Errors & Retries + retry-based-on-specific-errors.mdx
- Resource-safe streaming → Streams & Pipelines + stream-manage-resources.mdx
- Graceful shutdown → Queues & Background + execute-long-running-apps-with-runfork.mdx
- Service layer design → Layers & Services + model-dependencies-as-services.mdx
- HTTP server setup → HTTP & Routing + build-a-basic-http-server.mdx
- Schema validation → Config & Schema + define-contracts-with-schema.mdx
- Testing with mocks → Testing & Mocking + mocking-dependencies-in-tests.mdx
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.
- 2mo ago First seen · 82 lines · 24 tokens per session scan A db48c72ec95e
effect-index is a skill published in the GitHub repository mepuka/effect-ontology (5 stars, last pushed 10mo ago), licensed MIT. It adds 24 tokens to every session and 1,254 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 2026-08-31.
effect-index compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| effect-indexmepuka/effect-ontology | Skill | 5 | 10mo ago | MIT | A | 24 | Claude Code |
| no-bare-castsprisma/orm | Skill | 48k | yesterday | Apache-2.0 | A | 52 | Claude Code, Codex |
| aws-sst-developmentsickn33/agentic-awesome-skills | Skill | 49k | yesterday | MIT | A | 26 | Claude Code |
| league-akari-shard-developmentLeagueAkari/LeagueAkari | Skill | 4.7k | 5d ago | MIT | A | 58 | Claude Code, Codex |
| dd-code-generationDataDog/pup | Skill | 1.0k | yesterday | Apache-2.0 | A | 16 | Claude Code |
| fast-typescript-checkinternet-development/www-sacred | Skill | 1.6k | 2d ago | MIT | A | 84 | Claude Code, Codex |
| typescript-magicianmcollina/skills | Skill | 2.0k | 10d ago | MIT | A | 108 | Claude Code, Codex |