What is studio-api-contracts?

A set of instructions for changing API agreements in Junjo AI Studio. An API agreement defines how a backend endpoint, frontend, SDK, command-line tool, or other service exchanges requests and responses.

Use it when adding or changing an endpoint and updating its schemas, generated API description, frontend consumers, SDKs, command-line clients, or contract tests.

It helps keep the backend and every client consistent when routes, data formats, authentication, errors, or browser access rules change.

How mdrideout/junjo configures Claude Code and Codex

Reuse

Borrowing it

Nothing to install: this file belongs to mdrideout/junjo. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/mdrideout/junjo/master/.agents/skills/studio-api-contracts/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/mdrideout/junjo

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/mdrideout/junjo/studio-api-contracts/github.svg)](https://agentmods.dev/skills/mdrideout/junjo/studio-api-contracts)

Your own site

<a href="https://agentmods.dev/skills/mdrideout/junjo/studio-api-contracts"><img src="https://agentmods.dev/badge/skills/mdrideout/junjo/studio-api-contracts/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/mdrideout/junjo/studio-api-contracts"><img src="https://agentmods.dev/badge/skills/mdrideout/junjo/studio-api-contracts.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 341 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00035	$0.00341
Opus 5.5	$0.00014	$0.00136
Sonnet 5.5	$0.00007	$0.00068
Haiku 4.5	$0.00003	$0.00034

Measured 17d ago against content hash 655fc7f45093, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

studio-api-contracts 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 17d 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.

.agents/skills/studio-api-contracts/SKILL.md · 38 lines

What it actually says

Studio API Contracts

Contract Decisions

Backend routes and their Rust request and response types own REST contracts.
Generated OpenAPI is a transport artifact, not a hand-edited source.
Frontend Zod schemas and request code are consumers and change with the backend contract.
Authentication, cookies, status codes, and the {code, message} error body are part of the endpoint contract.
A cross-boundary change is incomplete until the producer and every affected consumer are validated together.

Surface To Inspect

apps/studio/backend/server/src/features/ and the owning backend tests
apps/studio/backend/server/src/app.rs, where every route is registered
apps/studio/backend/scripts/validate_rest_api_contracts.sh, which exports the OpenAPI document
apps/studio/frontend/backend/openapi.json
apps/studio/frontend/src/features/ or apps/studio/frontend/src/auth/
apps/studio/frontend/src/__tests__/contracts/
apps/studio/frontend/src/__tests__/integration/
SDK or CLI clients that call the same route

Routing

Use studio-backend-rust for backend implementation, studio-frontend-react for browser implementation, and studio-security-auth when the contract includes credentials or sessions. Validation commands remain owned by scoped AGENTS.md files; concrete behavior remains owned by code and tests.

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.

17d ago Changed · +2 lines 655fc7f45093
1mo ago First seen · 36 lines · 35 tokens per session scan A f955f8f33522

Subscribe to this mod's changes

studio-api-contracts is a skill published in the GitHub repository mdrideout/junjo (20 stars, last pushed 17d ago), licensed Apache-2.0. It adds 35 tokens to every session and 341 once invoked, about $0.0001 per session on Opus 5.5. 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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