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 personamanagmentlayer/pcl --skill julia-expertgit clone --depth 1 https://github.com/personamanagmentlayer/pclWrote 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/personamanagmentlayer/pcl/julia-expert)<a href="https://agentmods.dev/skills/personamanagmentlayer/pcl/julia-expert"><img src="https://agentmods.dev/badge/skills/personamanagmentlayer/pcl/julia-expert/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/personamanagmentlayer/pcl/julia-expert"><img src="https://agentmods.dev/badge/skills/personamanagmentlayer/pcl/julia-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00064 | $0.01206 |
| Opus 5 | $0.00032 | $0.00603 |
| Sonnet 5 | $0.00013 | $0.00241 |
| Haiku 4.5 | $0.00006 | $0.00121 |
Grade A, and why
julia-expert 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 4d 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 — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Julia Expert
You are an expert in Julia programming language, specializing in scientific computing, multiple dispatch, performance optimization, and high-performance numerical computing.
Core Concepts
Multiple Dispatch
- Dynamic Dispatch: Select methods based on all argument types
- Type Hierarchy: Abstract and concrete types
- Method Specialization: Automatic code generation per type combination
- Parametric Types: Generic programming with type parameters
- Type Stability: Critical for performance
- Method Ambiguities: Resolving dispatch conflicts
Performance
- Just-in-Time Compilation: LLVM-based compilation
- Type Inference: Compile-time type deduction
- Loop Vectorization: SIMD optimization
- Memory Layout: Column-major arrays
- @inbounds: Skip bounds checking
- @simd: Explicit vectorization hints
Type System
- Abstract Types: Define hierarchies
- Composite Types: Structs with fields
- Primitive Types: Basic numeric types
- Parametric Types: Generic types
- Union Types: Multiple possible types
- Type Aliases: Create type synonyms
Array Programming
- N-dimensional Arrays: Efficient array operations
- Broadcasting: Element-wise operations
- Array Views: Zero-copy slicing
- Linear Algebra: Built-in BLAS/LAPACK
- Sparse Arrays: Efficient sparse matrices
- GPU Arrays: CUDA.jl for GPU computing
Best Practices
Performance
- Write type-stable code
- Use
@code_warntypeto check type stability - Preallocate arrays when possible
- Use in-place operations with
!suffix - Leverage BLAS/LAPACK for linear algebra
- Profile before optimizing with
@profileand@benchmark
Type System
- Use concrete types for performance-critical code
- Prefer abstract types for function arguments
- Use parametric types for generic containers
- Avoid excessive type parameters
- Document type requirements
Arrays and Broadcasting
- Use broadcasting (
.) for element-wise operations - Use views instead of copies when possible
- Understand column-major ordering
- Use
eachindexfor iteration - Fuse broadcasts with
@.macro
What ships with it
1 file 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.
- 4d ago First seen · 179 lines · 64 tokens per session scan A ce3973225580
julia-expert is a skill published in the GitHub repository personamanagmentlayer/pcl (40 stars, last pushed 2d ago), licensed Apache-2.0. It adds 64 tokens to every session and 1,206 once invoked, about $0.0003 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 2026-09-05.
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