Borrowing it
Nothing to install: this file belongs to richardthe3rd/cambridge-beer-festival-app. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/richardthe3rd/cambridge-beer-festival-app/main/.claude/skills/architecture-contract/SKILL.mdgit clone --depth 1 https://github.com/richardthe3rd/cambridge-beer-festival-appWrote 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/richardthe3rd/cambridge-beer-festival-app/architecture-contract)<a href="https://agentmods.dev/skills/richardthe3rd/cambridge-beer-festival-app/architecture-contract"><img src="https://agentmods.dev/badge/skills/richardthe3rd/cambridge-beer-festival-app/architecture-contract/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/richardthe3rd/cambridge-beer-festival-app/architecture-contract"><img src="https://agentmods.dev/badge/skills/richardthe3rd/cambridge-beer-festival-app/architecture-contract.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00250 | $0.10985 |
| Opus 5 | $0.00125 | $0.05493 |
| Sonnet 5 | $0.00050 | $0.02197 |
| Haiku 4.5 | $0.00025 | $0.01098 |
Grade A, and why
architecture-contract 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 5d 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 — 640 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Architecture Contract
This is the map of how the app is built, not how to run it (see run-and-operate)
or how to fix a specific bug (see debugging-playbook / failure-archaeology).
Read this before adding code to lib/providers/, lib/domain/, lib/services/,
or lib/models/, or before trusting a review comment that claims a layer
boundary was crossed.
The app is released. Current version is 2026.9.0+2026090500
(pubspec.yaml:4), shipping to Cloudflare Pages and the Google Play
Internal track. Every fact below that says "no migration was needed" refers
to a pre-release decision. That era is over — see §3.
1. The layer contract
UI (lib/screens/, lib/widgets/)
context.watch<BeerProvider>() in build(); context.read<BeerProvider>() in callbacks
↓ calls provider methods, never touches controllers/repositories/services directly
BeerProvider (lib/providers/beer_provider.dart, ChangeNotifier — 1021 lines)
OWNS: the six UI signals — the drinks four (_isLoading/_isRefreshing/
_error/_refreshNotice) plus the festivals pair (_isFestivalsLoading/
_festivalsError, consumed only by festival_menu_sheets.dart),
persistence (calls repos + SharedPreferences), analytics (unawaited),
notifyListeners(), and orchestration between controllers/repositories.
↓ feeds loaded data in, reads derived views out
domain/controllers/ (pure, synchronous, NO Flutter / IO / async / analytics):
DrinkFilterController, UserDrinkStateController, FestivalController,
UserPreferencesController (the one exception: talks to SharedPreferences,
nothing else)
↓ use
domain/services/: DrinkFilterService, DrinkSortService (also pure)
↓
domain/repositories/ interfaces: DrinkRepository, FestivalRepository
impls: ApiDrinkRepository, ApiFestivalRepository — THIS is where IO happens
↓
services/: BeerApiService (HTTP), DrinkCacheService, UserDataStore
(SharedPreferencesUserDataStore), FestivalService, FestivalCacheService,
FestivalStorageService, AnalyticsService, EnvironmentService,
connectivity_io/web.dart
↓
models/: Drink (= Product + Producer), Festival, LogEntry, UserDrinkState
(a DERIVED view since v2 — see §3), MyFestivalEntry
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.
- 5d ago Changed · +8 lines c47b2b2a694d
- 8d ago Changed · +10 lines 6d83622e509d
- 12d ago First seen · 622 lines · 250 tokens per session scan A fb20eecc62bf
architecture-contract is a skill published in the GitHub repository richardthe3rd/cambridge-beer-festival-app (2 stars, last pushed yesterday), licensed MIT. It adds 250 tokens to every session and 10,985 once invoked, about $0.0013 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 2026-08-31.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
local-ai-agents
Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…
next-cache-components-adoption
Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…
chat-pet-sprite-creation
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…
insight-error-page
Write or audit an insight-kind error page for the Next.js dev overlay. Use when creating a new errors/ .mdx page, auditing an existing one, or checking that a page matches the framework fix cards. Covers page structure, title alignment, FixCard cards with Copy prompt button, code snippets, terminology verification…