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.
npx skills add alexastrum/skl --skill golang-samber-mogit clone --depth 1 https://github.com/alexastrum/sklWrote 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/alexastrum/skl/golang-samber-mo)<a href="https://agentmods.dev/skills/alexastrum/skl/golang-samber-mo"><img src="https://agentmods.dev/badge/skills/alexastrum/skl/golang-samber-mo/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/alexastrum/skl/golang-samber-mo"><img src="https://agentmods.dev/badge/skills/alexastrum/skl/golang-samber-mo.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 | $0.00085 | $0.02827 |
| Opus 5 | $0.00043 | $0.01413 |
| Sonnet 5 | $0.00017 | $0.00565 |
| Haiku 4.5 | $0.00009 | $0.00283 |
Grade A, and why
golang-samber-mo 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 12d 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.
This is a copy
89% identical to golang-samber-mo — 28 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 276 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Persona: You are a Go engineer bringing functional programming safety to Go. You use monads to make impossible states unrepresentable — nil checks become type constraints, error handling becomes composable pipelines.
Thinking mode: Use ultrathink when designing multi-step Option/Result/Either pipelines. Wrong type choice creates unnecessary wrapping/unwrapping that defeats the purpose of monads.
samber/mo — Monads and Functional Abstractions for Go
Go 1.18+ library providing type-safe monadic types with zero dependencies. Inspired by Scala, Rust, and fp-ts.
Official Resources:
This skill is not exhaustive. Please refer to library documentation and code examples for more information. Context7 can help as a discoverability platform.
go get github.com/samber/mo
For an introduction to functional programming concepts and why monads are valuable in Go, see Monads Guide.
Core Types at a Glance
| Type | Purpose | Think of it as... |
|---|---|---|
Option[T] |
Value that may be absent | Rust's Option, Java's Optional |
Result[T] |
Operation that may fail | Rust's Result<T, E>, replaces (T, error) |
Either[L, R] |
Value of one of two types | Scala's Either, TypeScript discriminated union |
EitherX[L, R] |
Value of one of X types | Scala's Either, TypeScript discriminated union |
Future[T] |
Async value not yet available | JavaScript Promise |
IO[T] |
Lazy synchronous side effect | Haskell's IO |
Task[T] |
Lazy async computation | fp-ts Task |
State[S, A] |
Stateful computation | Haskell's State monad |
Option[T] — Nullable Values Without nil
Represents a value that is either present (Some) or absent (None). Eliminates nil pointer risks at the type level.
import "github.com/samber/mo"
name := mo.Some("Alice") // Option[string] with value
empty := mo.None[string]() // Option[string] without value
fromPtr := mo.PointerToOption(ptr) // nil pointer -> None
// Safe extraction
name.OrElse("Anonymous") // "Alice"
empty.OrElse("Anonymous") // "Anonymous"
// Transform if present, skip if absent
upper := name.Map(func(s string) (string, bool) {
return strings.ToUpper(s), true
})
What ships with it
7 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.
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.
- 12d ago First seen · 276 lines · 85 tokens per session scan A 6ab54d2d9ab0
golang-samber-mo is a skill published in the GitHub repository alexastrum/skl (11 stars, last pushed 3mo ago), licensed MIT. It adds 85 tokens to every session and 2,827 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to golang-samber-mo, differing in 28 lines, and is treated as a copy.
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