Agent skill

Create App

End-to-end app creation from a single description. An agent skill from SethGammon/Citadel.

MITAuto-check passedProduct & Project Management

Install Create App

skills CLI

$ npx skills add SethGammon/Citadel --skill create-app -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install SethGammon/Citadel create-app --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/SethGammon/Citadel.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/create-app .claude/skills/create-app && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "create-app" agent skill from https://github.com/SethGammon/Citadel/tree/main/skills/create-app into .claude/skills/create-app/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "create-app", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/SethGammon/Citadel/tree/main/skills/create-app

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add SethGammon/Citadel --skill create-app -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install SethGammon/Citadel create-app --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/SethGammon/Citadel.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/create-app .agents/skills/create-app && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "create-app" agent skill from https://github.com/SethGammon/Citadel/tree/main/skills/create-app into .agents/skills/create-app/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "create-app", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add SethGammon/Citadel --skill create-app -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install SethGammon/Citadel create-app --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/SethGammon/Citadel.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/create-app .cursor/skills/create-app && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "create-app" agent skill from https://github.com/SethGammon/Citadel/tree/main/skills/create-app into .cursor/skills/create-app/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "create-app", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/SethGammon/Citadel.git --path skills/create-app

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add SethGammon/Citadel --skill create-app -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install SethGammon/Citadel create-app --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/SethGammon/Citadel.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/create-app .gemini/skills/create-app && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "create-app" agent skill from https://github.com/SethGammon/Citadel/tree/main/skills/create-app into .gemini/skills/create-app/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "create-app", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install SethGammon/Citadel create-app

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add SethGammon/Citadel --skill create-app -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/SethGammon/Citadel.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/create-app .github/skills/create-app && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "create-app" agent skill from https://github.com/SethGammon/Citadel/tree/main/skills/create-app into .github/skills/create-app/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "create-app", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add SethGammon/Citadel --skill create-app -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install SethGammon/Citadel create-app --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/SethGammon/Citadel.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/create-app .opencode/skills/create-app && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "create-app" agent skill from https://github.com/SethGammon/Citadel/tree/main/skills/create-app into .opencode/skills/create-app/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "create-app", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: create-app
GitHub stars: 922
Token cost: ~1.7k tokens
SKILL.md length: 812 words
Files: 3
Skills in repo: 48
Repo updated: Oct 1, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

End-to-end app creation from a single description. An agent skill from SethGammon/Citadel.

Works in 4 steps: CLASSIFY → EXECUTE TIER → VERIFY (All Tiers except 1) → …
Tasks that involve PRD writing
SKILL.md covers Orientation, Tier Detection, Protocol and Quality Gates, plus 2 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Create App is an agent skill from SethGammon/Citadel. End-to-end app creation from a single description. Five tiers: blank project, guided, templated, fully generated, or feature addition to existing codebase. Routes through PRD, architecture, and Archon campaign with verification at every step.

Its SKILL.md is about 1.7k tokens, which your agent loads only when the skill is triggered. The skill folder holds 3 other files (for example `__benchmarks__/existing-codebase.md` and `__benchmarks__/greenfield-vague.md`).

It sits in Product & Project Management, covering PRD writing. The repository describes itself as: The operating layer for Claude Code + OpenAI Codex: persistent project memory, intent routing, safety hooks, cost telemetry, and parallel agent fleets. The licence is MIT.

When your agent uses it

Tasks that involve PRD writing

Example prompts

“/create-app”

Workflow steps

4 steps, taken from the step headings in SKILL.md.

CLASSIFY
EXECUTE TIER
VERIFY (All Tiers except 1)
DELIVER

What it can do on your machine

Read from SKILL.md and the folder at commit e41ff1d. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Create App loads about 1.7k tokens when it runs. Until then it costs about 63 tokens; SKILL.md has 812 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~63
When it runs · the whole SKILL.md, loaded when a task matches: ~1.7k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from SethGammon/Citadel at commit e41ff1d, republished under its MIT licence (© SethGammon). 812 words, ~1,694 tokens.

Download SKILL.mdSave it as .claude/skills/create-app/SKILL.md (or your agent's skills folder). This skill also uses 2 other files; get the full folder from GitHub.

name: create-app
description: End-to-end app creation from a single description. Five tiers: blank project, guided, templated, fully generated, or feature addition to existing codebase. Routes through PRD, architecture, and Archon campaign with verification at every step.
license: MIT
user-invocable: true
auto-trigger: false
trigger_keywords: create app, build app, build me, make an app, new app, generate app, add auth, add payments, integrate
effort: max

/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.

Tier Classification

Input Pattern	Tier
"blank project", "scaffold", "new empty"	1
"help me build", "I want to create", "guide me"	2
"todo app", "blog", "dashboard", well-known app type	3
"build me [detailed]", "create [app]", confident description	4
"add [feature]", "implement [feature]", existing project + feature description	5
Ambiguous	Default to Tier 2 (safest)

Protocol

Step 1: CLASSIFY

Read the user's input. Determine the tier. Announce what you'll do in plain language — not tier numbers. If the classification is wrong, accept user overrides ("just scaffold it" → Tier 1, "just build it" → Tier 4).

Show full SKILL.md (374 more words)Show less

Step 2: EXECUTE TIER

Tier 1: Invoke /scaffold. Done.

Tier 2: /prd → user approves → /architect → user approves → Archon campaign → brief user after each major phase.

Tier 3: Check .planning/_templates/app-types/ for template → present PRD, ask for changes → /architect with template defaults → Archon campaign.

Tier 4:

/prd express mode (0-1 questions)
User approves PRD (only mandatory checkpoint)
/architect (auto-approve if all end conditions are machine-verifiable)
Archon campaign with ALL safety systems active:
- Direction alignment every 2 phases, quality spot-check every phase
- Circuit breakers: 3 failures = new approach, 5+ type errors = park
Execute autonomously until complete or parked
Run full verification of all PRD end conditions, present results

Tier 5 (Feature Addition):

Read existing codebase — file tree, package.json, key entry points, existing patterns
/prd in feature mode (max 2 questions)
User approves feature spec (one mandatory checkpoint)
/architect in existing codebase mode — Phase 0 always "Baseline" (run typecheck + tests, record counts). Auto-approve if machine-verifiable.
Archon campaign — every phase end condition includes "no new typecheck errors vs baseline" and "existing tests pass"
On completion: verify all feature end conditions + baseline regression check, present results

Step 3: VERIFY (All Tiers except 1)

Check each PRD end condition (run commands, check files, invoke /live-preview for visual checks). Report PASS / PARTIAL / FAIL with specifics.

Step 4: DELIVER

Present: what was built, what was verified, what needs attention, how to run it, and suggested next step (e.g., /postmortem or deploy command).

Quality Gates

PRD exists and is approved before any code is written
Architecture exists before Archon starts
Every campaign phase has machine-verifiable end conditions
Final verification checks all PRD end conditions
User receives a clear report of what was built and what needs attention

Fringe Cases

Vague requirements: Default to Tier 2 and ask clarifying questions before producing the PRD.

Project already initialized: Existing source files (src/, app/, package.json with deps) → automatically classify as Tier 5. Do not scaffold over an existing project.

If .planning/ does not exist: /prd and /architect will create it. If not possible, present inline and ask the user to run /do setup first.

Tier misclassification: Switch immediately on user correction without re-reading the input.

Exit Protocol

After the campaign completes and verification runs, output:

---HANDOFF---
- App: {name}
- Built: {feature ledger summary}
- Verified: {N}/{total} end conditions passed
- Status: {complete | partial | failed}
- To run: {start command}
- Next: {suggested next step, e.g., /postmortem or deploy command}
- Reversibility: amber -- multi-tier creation, revert the creation commits
---

Files

SKILL.md and 2 other files in skills/create-app of SethGammon/Citadel.

SKILL.md
__benchmarks__/existing-codebase.md
__benchmarks__/greenfield-vague.md

Open the folder on GitHubat commit e41ff1d

Compare with similar skills

Create App next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Create App compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Create App this skillSethGammon/Citadel	922	—	~1.7k	Automated safety check: Pass	MIT	6 days ago
CCPM Project Managementautomazeio/ccpm	8.4k	—	~1.1k	Automated safety check: Pass	MIT	6 mo ago
Ralph Tui Create Beadssubsy/ralph-tui	2.5k	1 repos	~2.6k	Automated safety check: Pass	MIT	1 mo ago
Trellis Brainstormanjiemo/SunnyBeach	178	7 repos	~4k	Automated safety check: Pass	Apache-2.0	26 days ago
Adversarial Speczscole/adversarial-spec	556	1 repos	~8.3k	Automated safety check: Notes	MIT	8 mo ago
Ralph Tui Create Beads Rustsubsy/ralph-tui	2.5k	1 repos	~2.8k	Automated safety check: Pass	MIT	1 mo ago

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Questions about Create App

What does Create App do?

End-to-end app creation from a single description. An agent skill from SethGammon/Citadel. Create App is an agent skill from SethGammon/Citadel. End-to-end app creation from a single description.

When should I use Create App?

Create App fits situations like: tasks that involve PRD writing.

How do I install Create App in Claude Code?

Run `npx skills add SethGammon/Citadel --skill create-app -a claude-code`. Or copy the skill folder (skills/create-app in SethGammon/Citadel) into .claude/skills/create-app in your project. Claude Code loads it when a task matches its description.

How do I install Create App in Codex?

Run `npx skills add SethGammon/Citadel --skill create-app -a codex`. Or copy the skill folder (skills/create-app in SethGammon/Citadel) into .agents/skills/create-app in your project. Codex loads it when a task matches its description.

Can I use Create App in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add SethGammon/Citadel --skill create-app -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/create-app, .gemini/skills/create-app, .github/skills/create-app and .opencode/skills/create-app in your project.

What does Create App need to run?

SKILL.md names no scripts, command-line tools or credentials: Create App is instructions for the agent only.

Does Create App access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Create App safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Create App use?

Create App is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Create App use?

About 1.7k tokens (SKILL.md is roughly 6.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Create App?

Skills that share tags, products or a category with Create App: CCPM Project Management (automazeio/ccpm, 8.4k stars), Ralph Tui Create Beads (subsy/ralph-tui, 2.5k stars), Trellis Brainstorm (anjiemo/SunnyBeach, 178 stars) and Adversarial Spec (zscole/adversarial-spec, 556 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Create App?

SethGammon (a GitHub user) maintains it in SethGammon/Citadel, which has 922 GitHub stars. The repository holds 48 skills in this directory. The repository was last updated on October 1, 2026.

Source: SethGammon/Citadel on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Create App

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

/create-app — From Description to Verified Application

Orientation

Tier Detection

Tier 1: Blank Project

Tier 2: Guided

Tier 3: Templated

Tier 4: Generated (Full Autonomy)

Tier 5: Feature Addition (Existing Codebase)

Tier Classification

Protocol

Step 1: CLASSIFY

Step 2: EXECUTE TIER

Step 3: VERIFY (All Tiers except 1)

Step 4: DELIVER

Quality Gates

Fringe Cases

Exit Protocol

Files

Compare with similar skills

Similar skills

More from SethGammon/Citadel

Related

Questions about Create App