A language guide for LikeC4, a tool that describes software systems in text files and generates interactive architecture diagrams. It covers .c4 and .likec4 files, project configuration, models, deployments, and views.

Use it when writing or checking LikeC4 files, validating or exporting diagrams, defining system relationships, creating deployment views, or answering LikeC4 command questions.

It prevents syntax and configuration mistakes when documenting how software components fit together.

How janmohammadi/adr-explorer configures Claude Code and Codex

Reuse

Borrowing it

Nothing to install: this file belongs to janmohammadi/adr-explorer. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/janmohammadi/adr-explorer/main/.agents/skills/likec4-dsl/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/janmohammadi/adr-explorer

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/janmohammadi/adr-explorer/likec4-dsl/github.svg)](https://agentmods.dev/skills/janmohammadi/adr-explorer/likec4-dsl)

Your own site

<a href="https://agentmods.dev/skills/janmohammadi/adr-explorer/likec4-dsl"><img src="https://agentmods.dev/badge/skills/janmohammadi/adr-explorer/likec4-dsl/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/janmohammadi/adr-explorer/likec4-dsl"><img src="https://agentmods.dev/badge/skills/janmohammadi/adr-explorer/likec4-dsl.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 5,263 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00073	$0.05263
Opus 5	$0.00036	$0.02632
Sonnet 5	$0.00015	$0.01053
Haiku 4.5	$0.00007	$0.00526

Measured 10d ago against content hash f5b9d619e0f4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

likec4-dsl 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 10d 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.

.agents/skills/likec4-dsl/SKILL.md · 408 lines

How it starts

The opening of the file, as written. The whole thing — 408 lines — stays where its author put it; the contents beside it link to each section on GitHub.

LikeC4 DSL Skill

Architecture-as-code tool. Describe systems in .c4/.likec4 files and LikeC4 generates interactive diagrams.

Rules

Projects - it is possible to have multiple likec4 projects in a workspace, project is determined by presence of a config file (.likec4rc, likec4.config.{ts,js,json}). LikeC4 files belong to the project of the nearest config file in the directory hierarchy.
Top-level statements — only import, specification, model, deployment, views, global are allowed. Blocks can repeat, but at least one per file must be present.
Multi-file merge — Top-level blocks across files are merged. For example, model { ... } blocks present in multiple files, parsed separately, and then merged into a single model.
Strings — 'single', "double" — all support multi-line. Escape quotes with backslash: \' or \".
Markdown — properties like summary/description/notes can contain Markdown. Use triple quotes ''' or """. Begin a new line after opening quotes and indent Markdown content for better formatting and syntax highlighting.
Comments — // single line and /* multi-line */ comments supported anywhere.
Identifier — letters, digits, hyphens, underscores only. No dots (dots are FQN separators). Can't start with a digit. Examples: customer, payment-service, frontendApp, queue-1. Critical: payment-api is valid; payment.api is NOT an identifier (dots separate FQN hierarchy). See references/identifier-validity.md.
FQN — Fully Qualified Name (FQN) is a dot-separated path to an element, MUST be unique within the project. Examples: customer, saas.backend.payment-service.paymentsApi, infra.eu.zone1.node1.
References — LikeC4 has lexical scoping with hoisting, nested scope may shadow outer, like in JavaScript. That scope does not carry across files: even with imports/includes in the same project, cross-file references must use full FQNs. Tiny reminder: backend.api does not survive a file boundary; across files write the full path such as cloud.backend.api.

Read the full file on GitHub · 408 lines

Files

What ships with it

17 files 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.

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.

10d ago First seen · 408 lines · 73 tokens per session scan A f5b9d619e0f4

Subscribe to this mod's changes

likec4-dsl is a skill published in the GitHub repository janmohammadi/adr-explorer (11 stars, last pushed 2mo ago), licensed MIT. It adds 73 tokens to every session and 5,263 once invoked, about $0.0004 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.

Design and UX

webgl-holographic-foil

A self-contained WebGL2 hero: thin-film interference over a crushed-foil surface whose palette shifts with the viewing angle; move the cursor to tilt the film.

nexu-io/open-design · 41 tokens

html-ppt-hermes-cyber-terminal

OpenDesign + BYOK: choosing and wiring your own model, hands-on — cost, quality, and the routing decision. Built as a decision-grade AI literacy deck for engineers, IT, applied-AI teams.

nexu-io/open-design · 53 tokens

html-ppt-taste-brutalist

16:9 HTML deck in tactical-telemetry / CRT-terminal taste. Deactivated-CRT charcoal slides, white-phosphor monospace, hazard-red accent, scanline overlay, ASCII syntax, density over decoration. Distilled from Leonxlnx/taste-skill brutalist-skill (Tactical Telemetry mode).

nexu-io/open-design · 78 tokens

adr-explorer: Skill for Claude Code