A guide to BESSER, a model-driven tool where a B-UML model describes a software domain and generators turn that model into code or documentation. A domain model describes things, their data, and how they relate.

Use it to create B-UML models, class diagrams, and generated Django, FastAPI, database, validation, React, or other supported project code.

It gives you a repeatable way to define requirements, validate the model, generate a starting point, and update the model when requirements change.

besser-user — Skill for Claude Code by BESSER-PEARL/BESSER-Skills

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 BESSER-PEARL/BESSER-Skills --skill besser-user

Clone the repo

git clone --depth 1 https://github.com/BESSER-PEARL/BESSER-Skills

Made for: Claude Code.

Or install besser, the plugin that ships this one along with the rest of its 4 skills.

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/besser-pearl/besser-skills/besser-user/github.svg)](https://agentmods.dev/skills/besser-pearl/besser-skills/besser-user)

Your own site

<a href="https://agentmods.dev/skills/besser-pearl/besser-skills/besser-user"><img src="https://agentmods.dev/badge/skills/besser-pearl/besser-skills/besser-user/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/besser-pearl/besser-skills/besser-user"><img src="https://agentmods.dev/badge/skills/besser-pearl/besser-skills/besser-user.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 343 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,237 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	$0.00343	$0.03237
Opus 5.5	$0.00137	$0.01295
Sonnet 5.5	$0.00069	$0.00647
Haiku 4.5	$0.00034	$0.00324

Measured 1mo ago against content hash 1d1ef81ca954, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

besser-user 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 1mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/scaffold_model.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/besser-user/SKILL.md · 288 lines

How it starts

The opening of the file, as written. The whole thing — 288 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Working with BESSER

BESSER is a model-driven platform: describe your domain as a model, then generators turn that model into running code. The model is the source of truth — when requirements change, update the model and regenerate. Never hand-edit generated code as your primary change.

Core workflow

1. Define requirements
2. Build a B-UML model (Python API, PlantUML, or web editor)
3. Validate the model: model.validate()
4. Pick a generator for your target platform
5. Generate code
6. Verify the output (run, test, inspect)
7. Iterate: update the model, regenerate

Two outcomes: code or documentation

A B-UML model is useful even if you never run a generator. Feed it to a generator for code, or embed it in a README/design doc as a correct, validate()-checked class diagram that documents any project. So reach for this skill whenever you need an accurate class diagram — not only when the project will use BESSER's generators.

Deliver it accordingly: default to a runnable .py file, or embed the same B-UML in Markdown when the request is documentation-oriented. For the full how-to — making the file self-contained, and the two ways the user runs or imports it — see references/delivering-models.md.

Don't deliver the diagram as a Mermaid block. This skill exists so the diagram is a real, validate()-checked B-UML model — not a throwaway ```mermaid classDiagram``` that drifts from the code. When asked for a class diagram, the deliverable is B-UML (the .py model and/or the same model embedded in Markdown); when a rendered image is wanted, produce an SVG/PNG from the B-UML — one call to BESSER's headless B-UML → SVG endpoint (POST https://editor.besser-pearl.org/besser_api/get-svg, send the .py), or Import → B-UML in the web editor, then export. A quick ASCII sketch is fine as an inline preview, but the authoritative artifact is always the B-UML model — not Mermaid.

Reference layout

This skill keeps SKILL.md short. Reach into references/ and scripts/ when you need depth. All references are verified against the BESSER version shown in the README badge; where behaviour changed after it, the reference says so.

Read the full file on GitHub · 288 lines

Files

What ships with it

14 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.

1mo ago Changed 1d1ef81ca954
2mo ago First seen · 288 lines · 343 tokens per session scan A 90bec2fd6d93

Subscribe to this mod's changes

besser-user is a skill published in the GitHub repository BESSER-PEARL/BESSER-Skills (9 stars, last pushed 17d ago), licensed Apache-2.0. It adds 343 tokens to every session and 3,237 once invoked, about $0.0014 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 2026-08-31.

Claude Code agent-skills ai-agents anthropic b-uml besser

besser-user next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
besser-userBESSER-PEARL/BESSER-Skills	Skill	9	17d ago	Apache-2.0	A	343	Claude Code
subagent-driven-developmentNousResearch/hermes-agent	Skill	261k	yesterday	MIT	A	17	Claude Code, Codex
mcporterNousResearch/hermes-agent	Skill	261k	yesterday	MIT	A	16	Claude Code, Codex
research-engineerdavila7/claude-code-templates	Skill	33k	yesterday	MIT	A	43	Claude Code, Codex
article-writingaffaan-m/ECC	Skill	298k	5d ago	MIT	A	57	Claude Code, Codex
safe-refactorJuliusBrussee/caveman	Skill	118k	yesterday	Apache-2.0	A	29	Claude Code, Codex
telegram-setupvellum-ai/vellum-assistant	Skill	1.5k	2d ago	MIT	A	22	Claude Code, Codex