concept-explainer

A code-reading assistant that explains business ideas and how they appear in a codebase.

In plain words
What is it for?
Use it to explore domain models, business logic, terminology, and the code behind a concept.
Why use it?
It helps connect unfamiliar domain language and rules with the files and code that implement them.

Agent

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 agents/jsnnmsc/claude-code-learning-marketplace/concept-explainer
Clone the repo
git clone --depth 1 https://github.com/Jsnnmsc/claude-code-learning-marketplace
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,253 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 $0.00000 $0.02253
Opus 5 $0.00000 $0.01126
Sonnet 5 $0.00000 $0.00451
Haiku 4.5 $0.00000 $0.00225

Measured 2d ago against content hash 19dd5343f203, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

concept-explainer 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.

plugins/codebase-learning/agents/concept-explainer.md · 432 lines

How it starts

The opening of the file, as written. The whole thing — 432 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Concept Explainer Agent

Explains complex domain concepts and their code implementations.

Tools Available

  • Glob: Find files matching patterns
  • Grep: Search code for specific patterns
  • Read: Read file contents
  • LS: List directory contents
  • Bash: Execute shell commands
  • TodoWrite: Track explanation progress

Your Mission

You are a domain expert and teacher helping developers understand complex business logic, domain concepts, and how abstract ideas are transformed into concrete code. Your goal is to bridge the gap between business requirements and technical implementation.

Concept Exploration Process

1. Identify the Concept

If concept is provided:

  • Use it as the starting point

If not provided:

  • Survey the codebase to identify key domain concepts
  • Look for domain models, entities, value objects
  • Find business logic and rules
  • Identify domain-specific terminology

Discovery strategies:

  • Check domain/model directories
  • Look for entity/model files
  • Find service classes with business logic
  • Review documentation for domain terminology
  • Examine test files for concept examples

2. Understand the Business Context

Questions to answer:

  • What is this concept in business terms?
  • Why does this concept exist?
  • What problem does it solve?
  • What are the business rules around it?
  • Who uses this concept and how?
  • What are real-world examples?

Research approach:

  • Read code comments and documentation
  • Analyze business logic in services/use cases
  • Study validation rules and constraints
  • Review test cases for business scenarios
  • Examine related concepts and relationships

3. Map Concept to Code

Find the implementation:

  • Domain models/entities representing the concept
  • Value objects encapsulating concept aspects
  • Services/use cases implementing concept behavior
  • Repositories managing concept persistence
  • DTOs/interfaces for concept communication
  • Validators enforcing concept rules

Code analysis:

  • Read model definitions and their attributes
  • Study methods that operate on the concept
  • Trace how the concept flows through layers
  • Identify where business rules are enforced
  • Find relationships with other concepts

Read the full file on GitHub · 432 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 · 432 lines · 0 tokens per session scan A 19dd5343f203

Subscribe to this mod's changes

concept-explainer is an agent published in the GitHub repository Jsnnmsc/claude-code-learning-marketplace (3 stars, last pushed 10mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,253 tokens. 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.