derive-tdd

derive-tdd is a command for Gemini CLI from AsiaOstrich/universal-dev-standards. It costs 0 tokens per session (440 once invoked), scanned A, original, no licence file.

A command for applying test-driven development, or TDD, to software design. TDD means writing a failing test before writing the code that makes it pass.

In plain words
What is it for?
Use it when deriving an implementation approach from tests and TDD practices.
Why use it?
It helps make expected behavior explicit before implementation starts.

Command for Gemini CLI

Part of the universal-dev-standards plugin — 55 skills, 53 commands, 10 agents, 1 hook shipped together

Install

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.

agentmods
npx agentmods add commands/asiaostrich/universal-dev-standards/derive-tdd
Clone the repo
git clone --depth 1 https://github.com/AsiaOstrich/universal-dev-standards

Made for: Gemini CLI.

Or install universal-dev-standards, the plugin that ships this one along with the rest of its 55 skills, 53 commands, 10 agents, 1 hook.

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 derive-tdd

README.md
[![agentmods](https://agentmods.dev/badge/commands/asiaostrich/universal-dev-standards/derive-tdd.svg)](https://agentmods.dev/commands/asiaostrich/universal-dev-standards/derive-tdd)
Your own site
<a href="https://agentmods.dev/commands/asiaostrich/universal-dev-standards/derive-tdd"><img src="https://agentmods.dev/badge/commands/asiaostrich/universal-dev-standards/derive-tdd.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 440 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00000 $0.00440
Opus 5 $0.00000 $0.00220
Sonnet 5 $0.00000 $0.00088
Haiku 4.5 $0.00000 $0.00044

Measured yesterday against content hash b87d187fbfb0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

derive-tdd 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 yesterday.

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.

.gemini/commands/derive-tdd.toml · 53 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. yesterday First seen · 53 lines · 0 tokens per session scan A b87d187fbfb0

Subscribe to this mod's changes

derive-tdd is a command published in the GitHub repository AsiaOstrich/universal-dev-standards (73 stars, last pushed today), with no licence file. It costs nothing until one of its globs matches a file; then it loads 440 tokens. 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 2026-09-03.