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/api-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/api-contract)<a href="https://agentmods.dev/skills/richardthe3rd/cambridge-beer-festival-app/api-contract"><img src="https://agentmods.dev/badge/skills/richardthe3rd/cambridge-beer-festival-app/api-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/api-contract"><img src="https://agentmods.dev/badge/skills/richardthe3rd/cambridge-beer-festival-app/api-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 | $0.00192 | $0.06777 |
| Opus 5 | $0.00096 | $0.03388 |
| Sonnet 5 | $0.00038 | $0.01355 |
| Haiku 4.5 | $0.00019 | $0.00678 |
Grade C, and why
api-contract scanned grade C with 1 finding 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 11d 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.
Recursive force deletehighDestructive command
rm -rf with a variable or a broad path is one typo away from removing the wrong tree.
rm -rf cloudflare-worker/src docs/code/api/openapi How it starts
The opening of the file, as written. The whole thing — 380 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API contract (proto-first)
The whole API surface — CatalogService (read-only festival/drink catalogue)
and MyFestivalService (personal state + aggregates) — is defined once as
Protocol Buffers in proto/cambeerfestival/festival/v1alpha/*.proto. The
proto is the source of truth. There is no gRPC server: google.api.http
annotations on each RPC define its REST route, and an OpenAPI v3 document
(docs/code/api/openapi/openapi.yaml, gitignored — always generated, never
committed) is derived from the proto for the hand-written Cloudflare Worker
and any HTTP client. That OpenAPI doc is published as a Redoc site to GitHub
Pages on every push to main (.github/workflows/api-docs.yml); PRs get it
attached as a downloadable artifact instead.
If you need the plain-English meaning of a term used below (AIP, D1,
workerd, etag, keyset pagination, CalVer, ...), see skill reference — this
skill assumes you already know what they mean and focuses on what this repo
specifically does with them.
1. Doctrine, in one paragraph
Design the resource in proto first (message + service + google.api.http
binding), never in the Worker. docs/code/api/openapi/openapi.yaml and
cloudflare-worker/src/api-types.ts are generated artifacts — both are
gitignored (proto/docs/code/api/.gitignore has openapi/;
cloudflare-worker/.gitignore has src/). Never hand-edit either; if a type
looks wrong, fix the .proto and regenerate. The same applies to
packages/myfestival_client (gitignored at the repo root, packages/) —
the generated Dart/Dio sync client for Flutter.
2. Edit workflow — exact commands
Run in this order after any .proto change (all dev-only tasks, so prefix
MISE_ENV=dev off Claude Code Web; on Claude Code Web the .miserc.toml
auto-env already includes dev, so plain ./bin/mise works there):
MISE_ENV=dev ./bin/mise run proto:format # buf format -w — formats .proto in place
MISE_ENV=dev ./bin/mise run proto:lint # buf lint — STANDARD ruleset (minus 2 exceptions, see §4)
MISE_ENV=dev ./bin/mise run proto:api-lint # AIP design-guideline linter (googleapis/api-linter)
MISE_ENV=dev ./bin/mise run proto:generate # buf generate -> docs/code/api/openapi/openapi.yaml
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.
- 11d ago First seen · 380 lines · 192 tokens per session scan C c45778558531
api-contract is a skill published in the GitHub repository richardthe3rd/cambridge-beer-festival-app (2 stars, last pushed yesterday), licensed MIT. It adds 192 tokens to every session and 6,777 once invoked, about $0.0010 per session on Opus 5. A static security scan graded it C with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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