Effect TS

What it does

When your agent uses it

• Analyzing TypeScript code using the Effect library
• Tasks that involve Database schema design
• Tasks that involve Error handling

Example prompts

• “/effect-ts”

Requirements

• Pre-approved tools (allowed-tools): Read, Grep, Glob

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

1. 1Effect is not just for async — Use Effect for any fallible operation
2. 2Immutability — Use Effect's immutable data structures (Data, Chunk, HashSet)
3. 3Type Safety — Track errors in types. No any or unknown in error channels
4. 4Composition — Build programs by composing small Effects
5. 5Schema-First — Define data models using Schema with branded types
6. 6Pattern Matching — Use Match for all branching over tagged unions (never switch/if-else on _tag)
7. 7Effect Data Types — Use Option (not null), Either (not ad-hoc), Duration (not raw ms), DateTime (not Date), BigDecimal (not floats)…

What it can do on your machine

Read from SKILL.md and the folder at commit 0422940. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Grep
  • Glob

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • pnpm

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md. Its commands use pnpm, which can reach the network depending on how they are called.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Effect TS loads about 2.3k tokens when it runs, and up to ~49k if it reads all its reference files. Until then it costs about 65 tokens; SKILL.md has 461 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~65

When it runs · the whole SKILL.md, loaded when a task matches

~2.3k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~49k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Without a licence we can't republish the file, so here is its outline and opening line. It has 461 words (~2,311 tokens).

name

effect-ts

allowed-tools

Read, Grep, Glob

Read the full SKILL.md on GitHub

Files

SKILL.md and 19 other files (references) in skills/curated/effect-ts of pedronauck/skills.

• SKILL.md
• references/api-platform-observability.md
• references/batching-and-caching.md
• references/class-patterns.md
• references/concurrency-and-resources.md
• references/construction-and-style.md
• references/control-flow-and-runtime.md
• references/core-patterns.md
• references/data-and-testing.md
• references/data-types.md
• references/error-handling-patterns.md
• references/foundations.md
• references/library-development-patterns.md
• references/pattern-matching.md
• references/quality-tooling-and-resources.md
• references/schema-errors-config.md
• references/schema-transforms-and-filters.md
• references/sink.md
• references/streams-deep-dive.md
• references/testing-patterns.md

Open the folder on GitHubat commit 0422940