orchestrator: Skill for Claude Code

.claude/skills/test-authoring/SKILL.md

test-authoring is a skill for Claude Code from c9r-io/orchestrator. It costs 58 tokens per session (1,054 once invoked), scanned A, original, MIT.

A guide for writing or improving unit tests and Playwright end-to-end tests. Unit tests check small pieces of code, while end-to-end tests check complete user flows in a running application.

In plain words
What is it for?
Use it to test new features, add missing unit or browser tests, and improve coverage in the Rust backend or React frontend.
Why use it?
It helps developers choose the right test scope, find coverage gaps, and follow the project's existing Rust, React, Vite, and Playwright layout.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is c9r-io/orchestrator's own configuration. It tells Claude Code how to work on orchestrator itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything orchestrator configures →

Reuse

Borrowing it

Nothing to install: this file belongs to c9r-io/orchestrator. 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/c9r-io/orchestrator/main/.claude/skills/test-authoring/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/c9r-io/orchestrator

Made for: Claude Code.

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.

agentmods badge for test-authoring

README.md
[![agentmods](https://agentmods.dev/badge/skills/c9r-io/orchestrator/test-authoring.svg)](https://agentmods.dev/skills/c9r-io/orchestrator/test-authoring)
Your own site
<a href="https://agentmods.dev/skills/c9r-io/orchestrator/test-authoring"><img src="https://agentmods.dev/badge/skills/c9r-io/orchestrator/test-authoring.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,054 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00058 $0.01054
Opus 5 $0.00029 $0.00527
Sonnet 5 $0.00012 $0.00211
Haiku 4.5 $0.00006 $0.00105

Measured 8d ago against content hash 3417405772a0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

test-authoring 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 8d 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.

.claude/skills/test-authoring/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Test Authoring

Write tests for newly implemented functionality, or improve an existing project's test suite by using coverage data to identify gaps.

In this repository, the Rust workspace spans core/ and crates/, while the React/Vite frontend and Playwright suite live under gui/. For other targets, discover their test layout before selecting commands.

Decide Scope

Confirm which of these the user wants:

  • Unit tests (backend and/or frontend)
  • E2E tests (usually Playwright)
  • Coverage improvement (and any target: e.g. "80%+ service layer")

If the user says "new feature implemented", treat the changed code as the test target (optimize for verifying behavior, not lines).

Discover Project Test Tooling

From repo root, identify:

  • Backend language:
    • Rust: core/Cargo.toml exists
    • Other: ask for the test command and coverage command
  • Frontend:
    • gui/package.json exists (TypeScript/React frontend)
  • E2E:
    • Look for Playwright in gui/playwright.config.ts and gui/package.json

Prefer scripts in gui/package.json and commands declared by the root Cargo workspace over inventing new ones.

Unit Tests (Backend)

Rust (core/)

Principles:

  • Keep tests fast and deterministic.
  • Prefer unit tests for business logic without Docker.
  • Mock boundaries (repositories, HTTP clients) using traits and mock libraries (e.g. mockall).

Placement:

  • For pure logic: colocate tests in core/src/** using #[cfg(test)] mod tests.
  • For API/behavior tests: use core/tests/** if the project has a test harness there.

Workflow:

  1. Identify behavior added/changed (inputs, outputs, error cases).
  2. Add tests for:
    • Happy path
    • Boundary conditions
    • Negative cases (validation, authz, not-found, conflict)
  3. Run backend tests (project-specific):
    • cargo test --workspace

Coverage (if requested):

  • Prefer cargo llvm-cov if configured, otherwise follow the project's existing coverage commands.
  • If no coverage tooling exists, propose adding cargo llvm-cov support (do not force-install tools without user confirmation).

Read the full file on GitHub · 123 lines

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.

  1. 8d ago First seen · 123 lines · 58 tokens per session scan A 3417405772a0

Subscribe to this mod's changes

test-authoring is a skill published in the GitHub repository c9r-io/orchestrator (21 stars, last pushed 7d ago), licensed MIT. It adds 58 tokens to every session and 1,054 once invoked, about $0.0003 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.