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-patterns-hub/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-patterns-hub)<a href="https://agentmods.dev/skills/mepuka/effect-ontology/effect-patterns-hub"><img src="https://agentmods.dev/badge/skills/mepuka/effect-ontology/effect-patterns-hub/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-patterns-hub"><img src="https://agentmods.dev/badge/skills/mepuka/effect-ontology/effect-patterns-hub.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 | $0.00047 | $0.04759 |
| Opus 5.5 | $0.00019 | $0.01904 |
| Sonnet 5.5 | $0.00009 | $0.00952 |
| Haiku 4.5 | $0.00005 | $0.00476 |
Grade A, and why
effect-patterns-hub 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 — 406 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Effect Patterns Hub
Purpose: Provide quick access to 130+ curated Effect-TS patterns from the EffectPatterns repository. Use this skill to find specific implementation patterns, compare approaches, and reference best practices.
Triggers
- Looking for a specific Effect pattern or idiom
- Need real-world examples of Effect concepts
- Want to see multiple approaches to the same problem
- Comparing implementation strategies
- Learning new Effect features
Pattern Library Location
Local Patterns: .claude/skills/effect-patterns-hub/patterns/
Documentation: docs/effect-patterns/
Count: 130+ patterns in MDX format
Quick Decision Tree
I need to...
Create Effects
- From value →
constructor-succeed-some-right.mdx - From sync code →
constructor-sync-async.mdx - From promise →
constructor-try-trypromise.mdx - From nullable →
constructor-from-nullable-option-either.mdx - Pre-resolved →
create-pre-resolved-effect.mdx
Transform & Compose
- Map values →
combinator-map.mdx - Chain effects →
combinator-flatmap.mdx - Sequence operations →
combinator-sequencing.mdx - Combine values →
combinator-zip.mdx - Filter →
combinator-filter.mdx - Conditional logic →
combinator-conditional.mdx - Process collections →
combinator-foreach-all.mdx
Control Flow
- Sequential logic →
write-sequential-code-with-gen.mdx - Business logic →
use-gen-for-business-logic.mdx - Pipe composition →
use-pipe-for-composition.mdx - Branching workflows →
conditionally-branching-workflows.mdx - Combinators →
control-flow-with-combinators.mdx - Repetition →
control-repetition-with-schedule.mdx
What ships with it
60 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- patterns/_README.review.md 39 KB
- patterns/_start_here.json 352 B
- patterns/access-config-in-context.mdx 1.7 KB
- patterns/accessing-current-time-with-clock.mdx 4.2 KB
- patterns/accumulate-multiple-errors-with-either.mdx 4.6 KB
- patterns/add-caching-by-wrapping-a-layer.mdx 4.7 KB
- patterns/add-custom-metrics.mdx 3.4 KB
- patterns/avoid-long-andthen-chains.mdx 1.9 KB
- patterns/beyond-the-date-type.mdx 3.8 KB
- patterns/brand-model-domain-type.mdx 1.9 KB
- patterns/brand-validate-parse.mdx 2.2 KB
- patterns/build-a-basic-http-server.mdx 3.6 KB
- patterns/combinator-conditional.mdx 2.3 KB
- patterns/combinator-error-handling.mdx 2.4 KB
- patterns/combinator-filter.mdx 2.3 KB
- patterns/combinator-flatmap.mdx 2.2 KB
- patterns/combinator-foreach-all.mdx 2.7 KB
- patterns/combinator-map.mdx 2.0 KB
- patterns/combinator-sequencing.mdx 3.0 KB
- patterns/combinator-zip.mdx 2.3 KB
- patterns/comparing-data-by-value-with-structural-equality.mdx 3.6 KB
- patterns/compose-scoped-layers.mdx 4.3 KB
- patterns/conditionally-branching-workflows.mdx 5.3 KB
- patterns/constructor-fail-none-left.mdx 1.9 KB
- patterns/constructor-from-iterable.mdx 2.0 KB
- patterns/constructor-from-nullable-option-either.mdx 2.5 KB
- patterns/constructor-succeed-some-right.mdx 1.9 KB
- patterns/constructor-sync-async.mdx 2.1 KB
- patterns/constructor-try-trypromise.mdx 2.1 KB
- patterns/control-flow-with-combinators.mdx 2.0 KB
- patterns/control-repetition-with-schedule.mdx 3.7 KB
- patterns/create-a-testable-http-client-service.mdx 5.3 KB
- patterns/create-managed-runtime-for-scoped-resources.mdx 2.0 KB
- patterns/create-pre-resolved-effect.mdx 1.9 KB
- patterns/create-reusable-runtime-from-layers.mdx 1.7 KB
- patterns/data-array.mdx 2.1 KB
- patterns/data-bigdecimal.mdx 2.1 KB
- patterns/data-case.mdx 2.1 KB
- patterns/data-cause.mdx 2.2 KB
- patterns/data-chunk.mdx 2.0 KB
- patterns/data-class.mdx 2.5 KB
- patterns/data-datetime.mdx 2.1 KB
- patterns/data-duration.mdx 1.8 KB
- patterns/data-either.mdx 2.1 KB
- patterns/data-exit.mdx 2.0 KB
- patterns/data-hashset.mdx 2.1 KB
- patterns/data-option.mdx 2.0 KB
- patterns/data-redacted.mdx 1.8 KB
- patterns/data-ref.mdx 2.0 KB
- patterns/data-struct.mdx 1.9 KB
- patterns/data-tuple.mdx 1.9 KB
- patterns/decouple-fibers-with-queue-pubsub.mdx 7.5 KB
- patterns/define-config-schema.mdx 1.9 KB
- patterns/define-contracts-with-schema.mdx 3.2 KB
- patterns/define-tagged-errors.mdx 2.5 KB
- patterns/distinguish-not-found-from-errors.mdx 3.8 KB
- patterns/effect-atom-derived.mdx 12 KB
- patterns/effect-atom-mutations.mdx 12 KB
- patterns/effect-atom-result-handling.mdx 14 KB
- patterns/effects-are-lazy.mdx 1.8 KB
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 · 406 lines · 47 tokens per session scan A 22beb7ea1b92
effect-patterns-hub is a skill published in the GitHub repository mepuka/effect-ontology (5 stars, last pushed 10mo ago), licensed MIT. It adds 47 tokens to every session and 4,759 once invoked, about $0.0002 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-patterns-hub compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| effect-patterns-hubmepuka/effect-ontology | Skill | 5 | 10mo ago | MIT | A | 47 | 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 |