julia-activate

julia-activate is a skill for Claude Code, Codex from samtalki/AgentREPL.jl. It costs 13 tokens per session (286 once invoked), scanned A, original, Apache-2.0.

A command for selecting which Julia project environment the current session uses. A Julia environment controls the packages and versions available to a project.

In plain words
What is it for?
Use it to activate a Julia project or versioned environment, then optionally install dependencies listed in its Project.toml file.
Why use it?
It prevents work from running with the wrong dependencies and lets the session use a project directory, a named environment, or the current folder.

Skill for Claude CodeCodex

Part of the julia plugin — 10 skills, 1 hook, 1 MCP server shipped together

Install

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.

agentmods
npx agentmods add skills/samtalki/agentrepl.jl/julia-activate
Any agent
npx skills add samtalki/AgentREPL.jl --skill julia-activate
Clone the repo
git clone --depth 1 https://github.com/samtalki/AgentREPL.jl

Made for: Claude Code, Codex.

Or install julia, the plugin that ships this one along with the rest of its 10 skills, 1 hook, 1 MCP server.

Wrote 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.

agentmods badge for julia-activate

README.md
[![agentmods](https://agentmods.dev/badge/skills/samtalki/agentrepl.jl/julia-activate.svg)](https://agentmods.dev/skills/samtalki/agentrepl.jl/julia-activate)
Your own site
<a href="https://agentmods.dev/skills/samtalki/agentrepl.jl/julia-activate"><img src="https://agentmods.dev/badge/skills/samtalki/agentrepl.jl/julia-activate.svg" alt="Measured on agentmods" height="20"></a>
Per session 13 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 286 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00013 $0.00286
Opus 5 $0.00006 $0.00143
Sonnet 5 $0.00003 $0.00057
Haiku 4.5 $0.00001 $0.00029

Measured 3d ago against content hash 387e7144fc79, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

julia-activate 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 3d 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.

claude-plugin/skills/julia-activate/SKILL.md · 43 lines

What it actually says

Julia Activate

Activate a Julia project or environment for the current session.

Arguments

  • path - Path to project directory, "." for current directory, or named environment like "@v1.10"

Instructions

  1. Parse the user's argument to determine the path:

    • If no argument or ".", activate the current working directory
    • If a path is given, use that path
    • If starts with "@", it's a named environment
  2. Call activate with the path

  3. After activation, offer to run pkg(action="instantiate") to install dependencies if the project has a Project.toml

Examples

/julia:julia-activate .
/julia:julia-activate /path/to/MyProject
/julia:julia-activate @v1.10

Notes

  • Activating a project changes where packages are installed/loaded from
  • Use pkg(action="instantiate") after activation to install dependencies
  • The activated environment persists across reset calls
  • Use info to see the currently active project
Changes

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.

  1. 3d ago First seen · 43 lines · 13 tokens per session scan A 387e7144fc79

Subscribe to this mod's changes

julia-activate is a skill published in the GitHub repository samtalki/AgentREPL.jl (6 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 13 tokens to every session and 286 once invoked, about $0.0001 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 2026-08-31.

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