agentenv Development Guide

A development guide for a project with a Rust command-line tool and core library, plus a Visual Studio Code extension. It documents where the code lives, how to test and format it, and the conventions for each part.

In plain words
What is it for?
Use it when developing the agentenv CLI, its core library, or its VS Code extension, including tests, configuration, error handling, and command registration.
Why use it?
It gives contributors a shared way to work across Rust and TypeScript instead of guessing which commands, patterns, or directories to use.

Instructions file

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 instructions/eduardoarantes/agentenv/claude-md
Clone the repo
git clone --depth 1 https://github.com/eduardoarantes/agentenv
Per session 2,213 This file is loaded in full into every session.
When invoked 2,213 The same file — it is already loaded in full.
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 $0.02213 $0.02213
Opus 5 $0.01107 $0.01107
Sonnet 5 $0.00443 $0.00443
Haiku 4.5 $0.00221 $0.00221

Measured 2d ago against content hash 72436f0af1e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agentenv Development Guide 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.

CLAUDE.md · 252 lines

How it starts

The opening of the file, as written. The whole thing — 252 lines — stays where its author put it; the contents beside it link to each section on GitHub.

agentenv Development Guide

This file describes the three development areas of agentenv — the Rust CLI (agentenv), the core library (agentenv-core), and the VS Code extension (vscode) — and the conventions, scope, and useful commands for each.

Development areas

Rust core and CLI

Purpose: Rust core library and CLI development with TDD focus

Scope:

  • crates/agentenv-core/ - Core library logic
  • crates/agentenv-cli/ - CLI implementation
  • Unit tests and integration tests

Skills:

  • Test-driven development (write tests first)
  • Error handling with thiserror
  • Async/await with tokio
  • Configuration parsing (YAML/JSON)
  • File system operations

Commands:

  • cargo test - Run all tests
  • cargo clippy - Lint checks
  • cargo fmt - Format code
  • cargo build - Build project

VS Code extension

Purpose: VS Code extension development

Scope:

  • vscode/src/ - TypeScript extension code
  • Extension manifest and configuration
  • Integration with agentenv CLI

Skills:

  • VS Code API knowledge
  • TypeScript strict mode
  • ESLint and Prettier formatting
  • Extension lifecycle (activation, deactivation)
  • Command registration

Commands:

  • npm run compile - Compile TypeScript
  • npm run lint - ESLint checks
  • npm run format - Prettier formatting

CLI ↔ extension integration

Purpose: Design and implement integration between CLI and extension

Scope:

  • Cross-crate communication
  • Plugin resolution flow
  • Symlink management
  • Target-tool integration

Skills:

  • Architectural patterns
  • API design
  • Error propagation
  • Configuration synchronization

Commands:

  • Document integration points
  • Design data flows
  • Implement error contracts

Source-driven canonical pipelines

.agentrc.yaml declares a single source: <tool> — currently claude-code. For every capability (hooks, skills, agents), sync:

  1. Reads the source's native layout losslessly into a canonical YAML under <project>/.agentenv/<capability>.canonical.yaml. Open-map frontmatter plus an explicit Native-style escape hatch (for hooks) ensure no information is dropped between source and canonical.
  2. Renders the canonical out to every configured non-source target via per-capability writers. Each writer reports drops for fields/items it cannot represent; nothing is silently lost.

Read the full file on GitHub · 252 lines

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. 2d ago First seen · 252 lines · 2,213 tokens per session scan A 72436f0af1e1

Subscribe to this mod's changes

agentenv Development Guide is an instructions file published in the GitHub repository eduardoarantes/agentenv (5 stars, last pushed 3mo ago), licensed MIT. It adds 2,213 tokens to every session, about $0.0111 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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