create-app

An end-to-end workflow for creating an application from a description, from an empty project or template through planning, design, implementation, and checks.

In plain words
What is it for?
Use it to start a new app, create a blank project, build a familiar app type such as a blog or dashboard, or add a feature when the workflow supports it.
Why use it?
It gives a new application a structured path from an idea to a verified result, with approval points during the work.

Skill for Claude CodeCodex

Part of the Citadel plugin — 48 skills, 7 agents, 2 MCP servers shipped together

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 skills/sethgammon/citadel/create-app
Any agent
npx skills add SethGammon/Citadel --skill create-app
Clone the repo
git clone --depth 1 https://github.com/SethGammon/Citadel

Made for: Claude Code, Codex.

Or install Citadel, the plugin that ships this one along with the rest of its 48 skills, 7 agents, 2 MCP servers.

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,621 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 $0.00052 $0.01621
Opus 5 $0.00026 $0.00811
Sonnet 5 $0.00010 $0.00324
Haiku 4.5 $0.00005 $0.00162

Measured 3d ago against content hash 30de1a93eddf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-app 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 3d 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.

skills/create-app/SKILL.md · 153 lines

How it starts

The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/create-app — From Description to Verified Application

Orientation

Use when: building a new app from scratch -- full scaffold, design system, and feature set from a single description. Don't use when: adding a feature to an existing app (use /marshal or /archon); generating a single component (use /scaffold).

Tier Detection

Use when the user wants to create an app, add a feature, or scaffold a project. Classify the input into one of five tiers:

Tier 1: Blank Project

  • Trigger: "create a blank project", "new project", "scaffold"
  • Action: Run /scaffold with stack detection. No PRD, no architecture.

Tier 2: Guided

  • Trigger: "I want to build...", "help me create...", description with questions
  • Action: /prd → user approves → /architect → user approves → /archon
  • Human checkpoints: after PRD, after architecture, before each major phase.

Tier 3: Templated

  • Trigger: Describes a well-known app type ("a todo app", "a blog", "a dashboard with auth")
  • Action: Load template PRD if available → /architect with template defaults → /archon
  • Template detection: check .planning/_templates/app-types/ for matching templates. If no template matches, fall through to Tier 2.

Tier 4: Generated (Full Autonomy)

  • Trigger: "build me [detailed description]", "create [app] and deploy it"
  • Action: /prd (minimal questions) → /architect (auto-approve if confidence high) → /archon with self-correction loop
  • Human checkpoints: after PRD only. Architecture and execution are autonomous.
  • Safety: all Archon self-correction mechanisms active. Direction alignment every 2 phases. Quality spot-checks every phase. Circuit breakers armed.

Tier 5: Feature Addition (Existing Codebase)

  • Trigger: existing project + feature description ("add auth", "add a dashboard", "add dark mode")
  • Detection: project has source files (src/, app/, lib/, package.json with deps) AND description is a feature, not a standalone app
  • Action: /prd in feature mode → /architect in existing codebase mode → /archon
  • Key differences from greenfield tiers:
    • PRD reads existing codebase before asking questions
    • Architecture describes changes to existing files, not a standalone system
    • Phase 0 is always "Baseline" — record current typecheck/test state
    • Every phase end condition includes "no new typecheck errors" + "existing tests pass"
    • Risk register always includes "regression in existing functionality"
  • Human checkpoints: after feature spec (PRD). Architecture can auto-approve if the feature is well-scoped and all conditions are machine-verifiable.

Read the full file on GitHub · 153 lines

Files

What ships with it

2 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.

  1. 3d ago First seen · 153 lines · 52 tokens per session scan A 30de1a93eddf

Subscribe to this mod's changes

create-app is a skill published in the GitHub repository SethGammon/Citadel (914 stars, last pushed 6d ago), licensed MIT. It adds 52 tokens to every session and 1,621 once invoked, about $0.0003 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.

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