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.
npx skills add nathanonn/agent-skills --skill webg-spec-to-goalgit clone --depth 1 https://github.com/nathanonn/agent-skillsWrote 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.
[](https://agentmods.dev/skills/nathanonn/agent-skills/webg-spec-to-goal)<a href="https://agentmods.dev/skills/nathanonn/agent-skills/webg-spec-to-goal"><img src="https://agentmods.dev/badge/skills/nathanonn/agent-skills/webg-spec-to-goal/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.
<a href="https://agentmods.dev/skills/nathanonn/agent-skills/webg-spec-to-goal"><img src="https://agentmods.dev/badge/skills/nathanonn/agent-skills/webg-spec-to-goal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00201 | $0.05776 |
| Opus 5 | $0.00101 | $0.02888 |
| Sonnet 5 | $0.00040 | $0.01155 |
| Haiku 4.5 | $0.00020 | $0.00578 |
Grade A, and why
webg-spec-to-goal 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 12d 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.
How it starts
The opening of the file, as written. The whole thing — 469 lines — stays where its author put it; the contents beside it link to each section on GitHub.
webg-spec-to-goal — Vague Game Idea → Complete Codex /goal Project
Turn a rough web game idea into a runnable Phaser 3 project scaffold plus every goal folder Codex /goal needs to build it autonomously:
my-game/
├── AGENTS.md
├── goals-plan.md
├── goals/
│ ├── 00-foundation/ GOAL.md VERIFY.md PROGRESS.md
│ ├── 01-core-mechanic/ GOAL.md VERIFY.md PROGRESS.md
│ ├── ...
│ └── NN-polish/ GOAL.md VERIFY.md PROGRESS.md
├── src/ runnable game skeleton
├── tests/ Playwright config + helpers
└── public/ assets directories
Games naturally decompose into 5-8 goals following a universal build order. This skill generates all goals at once — no checkpoint between plan and generation.
Extend mode: This skill also supports extending an existing game with new features. When the user explicitly states they want to extend an existing game, the skill reads the current project state and generates additional goals that continue the sequence.
Why this skill exists
Games have a predictable build order: scaffold → core mechanic → enemies/content → progression → UI → polish. This skill exploits that pattern to collapse the entire "idea → goal bundle" pipeline into one conversation that:
- auto-detects genre from the description and tailors everything to it
- asks 2-3 rounds of clarifying questions (each with options + recommendation)
- writes a runnable scaffold (boots to a blank Phaser scene out of the box)
- generates all goal folders at once with genre-aware decomposition
- bakes in state bridge verification (
window.__GAME_STATE__+ Playwright)
Genre system
Five base genres, each with known variants:
| Genre | Variants | Physics | Key Data Structures |
|---|---|---|---|
| shoot-em-up | bullet hell, shmup, Raiden-type, vertical/horizontal shooter | Arcade | bullet pools, wave spawners, hitboxes |
| card-game | solitaire, matching, deck-builder, poker variant | None | deck, hand, discard pile, card state |
| platformer | endless runner, side-scroller, precision platformer | Arcade | tilemap, player body, collectibles |
| tower-defense | lane defense, creep wave, placement strategy | None (path-based) | tower registry, enemy path, wave queue |
| puzzle | match-3, sliding, Tetris-type, word game | None or Arcade | grid state, match detection, gravity |
What ships with it
8 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.
- references/agents-template.md 9.5 KB
- references/genre-templates.md 31 KB
- references/goal-template.md 6.5 KB
- references/goals-plan-template.md 4.3 KB
- references/progress-template.md 2.3 KB
- references/qc-checkpoint-template.md 8.1 KB
- references/scaffold-templates.md 14 KB
- references/verify-template.md 7.8 KB
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.
- 12d ago First seen · 469 lines · 201 tokens per session scan A 1afa8a1fa624
webg-spec-to-goal is a skill published in the GitHub repository nathanonn/agent-skills (19 stars, last pushed 23d ago), licensed MIT. It adds 201 tokens to every session and 5,776 once invoked, about $0.0010 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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