A writing guide for rackdiag, a notation for showing equipment placed in a server rack.

Use it to document servers, switches, power units, load balancers, and other rack-mounted equipment.

It provides a compact way to record rack height, device positions, and equipment sizes.

rackdiag — Skill for Claude Code and Codex by antoinebou12/uml-mcp

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.

Any agent

npx skills add antoinebou12/uml-mcp --skill rackdiag

Clone the repo

git clone --depth 1 https://github.com/antoinebou12/uml-mcp

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/antoinebou12/uml-mcp/rackdiag/github.svg)](https://agentmods.dev/skills/antoinebou12/uml-mcp/rackdiag)

Your own site

<a href="https://agentmods.dev/skills/antoinebou12/uml-mcp/rackdiag"><img src="https://agentmods.dev/badge/skills/antoinebou12/uml-mcp/rackdiag/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/antoinebou12/uml-mcp/rackdiag"><img src="https://agentmods.dev/badge/skills/antoinebou12/uml-mcp/rackdiag.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 443 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	$0.00057	$0.00443
Opus 5.5	$0.00023	$0.00177
Sonnet 5.5	$0.00011	$0.00089
Haiku 4.5	$0.00006	$0.00044

Measured 14d ago against content hash 735ba537476f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

rackdiag 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 14d 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.

.skill/skills/rackdiag/SKILL.md · 57 lines

What it actually says

rackdiag diagram (uml-mcp)

diagram_type: rackdiag
Backend: rackdiag
Output formats: png, svg, pdf

Rack and server layout diagrams (blockdiag family)

Load the workflow skill uml-mcp-diagrams for URL-first replies, progressive discovery, and which MCP tool to call. This file is notation only; it does not add an MCP tool.

Styling

NU; height and [NU] item sizes; keep labels ≤ rack width.
No MCP theme param.

Starter template

rackdiag {
  16U;
  1: Server 1;
  2: Server 2;
  3: Switch;
}

Example

rackdiag {
  16U;
  1: UPS [2U];
  3: DB Server;
  4: Web Server;
  5: Web Server;
  6: Web Server;
  7: Load Balancer;
  8: L3 Switch;
}

Render with uml-mcp

Set diagram_type to rackdiag exactly.
Call validate_uml when the source is untrusted (prefer strict: true for Mermaid sequence).
Call generate_uml, generate_uml_image (chat PNG), or generate_uml_batch.
Pass theme when this skill's Themes section lists supported values.
Surface the returned url / playground (see the workflow skill).

Confirm formats with uml://formats or list_diagram_types when unsure.

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.

14d ago First seen · 57 lines · 57 tokens per session scan A 735ba537476f

Subscribe to this mod's changes

rackdiag is a skill published in the GitHub repository antoinebou12/uml-mcp (109 stars, last pushed yesterday), licensed MIT. It adds 57 tokens to every session and 443 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-10-24.

mcp uml

rackdiag next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
rackdiagantoinebou12/uml-mcp	Skill	109	yesterday	MIT	A	57	Claude Code, Codex
detailed-designpan94u/forge	Skill	40	5d ago	none	A	27	Claude Code
writing-skillstakaakit/superpowers-uml	Skill	12	1mo ago	none	A	20	Claude Code
brainstormingtakaakit/superpowers-uml	Skill	12	1mo ago	none	A	37	Claude Code
finishing-a-development-branchtakaakit/superpowers-uml	Skill	12	1mo ago	none	A	27	Claude Code
systematic-debuggingtakaakit/superpowers-uml	Skill	12	1mo ago	none	A	21	Claude Code
test-driven-developmenttakaakit/superpowers-uml	Skill	12	1mo ago	none	A	17	Claude Code