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 agentmods add rules/nedcodes-ok/cursorrules-collection/scalagit clone --depth 1 https://github.com/nedcodes-ok/cursorrules-collectionWhat 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 | $0.00425 | $0.00425 |
| Opus 5 | $0.00212 | $0.00212 |
| Sonnet 5 | $0.00085 | $0.00085 |
| Haiku 4.5 | $0.00042 | $0.00042 |
Grade A, and why
scala 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 2d 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.
What it actually says
Scala Cursor Rules
You are an expert Scala 3 developer. Follow these rules:
Type System
- Leverage the type system: encode invariants in types, not runtime checks
- Use opaque types for type-safe wrappers without runtime overhead
- Union types (A | B) over inheritance for simple alternatives
- Intersection types (A & B) for combining capabilities
- given/using over implicit for context parameters
Functional Patterns
- Immutable by default: val not var, case class not class
- Option over null, Either over exceptions for expected failures
- Pattern matching with exhaustivity checking — handle all cases
- For-comprehensions for chaining Option/Either/Future/IO
- Avoid return statements — last expression is the return value
Error Handling
- Either[Error, A] for business errors with typed error channels
- Try for wrapping Java exceptions at boundaries
- Never throw exceptions in pure functions
- Use cats-effect IO or ZIO for effectful error handling
- Accumulate errors with Validated/NonEmptyList, not fail-fast
Collections
- Use immutable collections from scala.collection.immutable
- LazyList for potentially infinite or expensive sequences
- view for lazy intermediate operations on large collections
- Avoid mutable collections except in performance-critical local scope
- Pattern match on collections: case head :: tail, case Nil
Architecture
- Tagless final or direct style with effect types for dependency injection
- Companion objects for smart constructors and factory methods
- Traits for interfaces, abstract classes only when Java interop needed
- Package by feature, not by layer
- Keep side effects at the edges — pure core, effectful shell
Build & Tooling
- sbt or scala-cli for builds
- Scalafmt for formatting — non-negotiable
- Wartremover or Scalafix for catching anti-patterns
- Cross-compile for library code
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.
- 2d ago First seen · 51 lines · 425 tokens per session scan A 99ce67581320
scala is a cursor rule published in the GitHub repository nedcodes-ok/cursorrules-collection (37 stars, last pushed 6mo ago), licensed MIT. It adds 425 tokens to every session, about $0.0021 per session on Opus 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 2026-08-30.