04-Design

04-Design is an agent for Claude Code from jonathan-vella/apex-accelerator. It costs 36 tokens per session (1,952 once invoked), scanned A, original, MIT.

An optional design step for approved Azure cloud architectures. It creates architecture diagrams, Architecture Decision Records (written explanations of important design choices), and requested cost-estimate handoffs.

In plain words
What is it for?
Use it to produce reproducible Python, PNG, and SVG architecture diagrams, decision records, and optional cost estimates under the project output folder.
Why use it?
It records how an approved design is structured and why significant choices were made before later governance or infrastructure work.

Agent for Claude Code

Written for Claude Code: user-invocable in frontmatter. Also seen: model in frontmatter; mentions subagents.

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/jonathan-vella/apex-accelerator/04-design
Clone the repo
git clone --depth 1 https://github.com/jonathan-vella/apex-accelerator

Made for: Claude Code.

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.

agentmods badge for 04-Design

README.md
[![agentmods](https://agentmods.dev/badge/agents/jonathan-vella/apex-accelerator/04-design.svg)](https://agentmods.dev/agents/jonathan-vella/apex-accelerator/04-design)
Your own site
<a href="https://agentmods.dev/agents/jonathan-vella/apex-accelerator/04-design"><img src="https://agentmods.dev/badge/agents/jonathan-vella/apex-accelerator/04-design.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,952 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 5.1 $0.00036 $0.01952
Opus 5 $0.00018 $0.00976
Sonnet 5 $0.00007 $0.00390
Haiku 4.5 $0.00004 $0.00195

Measured 6d ago against content hash 2e536b315096, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

04-Design 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 6d 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.

.github/agents/04-design.agent.md · 191 lines

How it starts

The opening of the file, as written. The whole thing — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Design Agent

Step 3 is optional. Users may skip to governance discovery or IaC planning.

<context_awareness> Keep context lean. Read each required skill once, use apex-recall show <project> --json for cached decisions, and never edit upstream artifacts. All diagrams use the python-diagrams skill and its shared diagram_io.py helper. </context_awareness>

Operating frame

Shared rules live in agent-operating-frame.instructions.md.

  • Generate design artifacts only: architecture diagrams, ADRs, and optional cost-estimate handoffs.
  • Never generate IaC or change the approved architecture without an ADR.
  • Read decisions.review_depth; only deep triggers the optional ADR review.
  • Use medium effort for normal diagram and ADR work. Use high effort only for unusually large topologies or comparison of ADR alternatives.

<output_contract>

Output contract

Write requested artifacts under agent-output/{project}/:

  • 03-des-diagram.py, 03-des-diagram.png, and 03-des-diagram.svg
  • 03-des-adr-NNNN-{slug}.md, one per significant decision
  • 03-des-cost-estimate.md, when requested

The Python source is mandatory and must reproduce both rendered siblings. Every generated markdown file includes > Generated by design agent | {YYYY-MM-DD}.

Artifact validation belongs to Lefthook and Challenger; do not run Markdown lint directly against agent-output/**.

</output_contract>

Inputs

Before generating artifacts:

  1. Read agent-output/{project}/02-architecture-assessment.md.
  2. Read agent-output/{project}/01-requirements.md for actors and critical flows.
  3. Read .github/skills/azure-defaults/SKILL.md.
  4. Read .github/skills/python-diagrams/SKILL.md when diagrams are in scope.
  5. Read .github/skills/azure-adr/SKILL.md when ADRs are in scope.
  6. Read .github/skills/azure-artifacts/SKILL.md only for a cost estimate.

Read the full file on GitHub · 191 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. 6d ago First seen · 191 lines · 36 tokens per session scan A 2e536b315096

Subscribe to this mod's changes

04-Design is an agent published in the GitHub repository jonathan-vella/apex-accelerator (50 stars, last pushed 4d ago), licensed MIT. It adds 36 tokens to every session and 1,952 once invoked, about $0.0002 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.