Borrowing it
Nothing to install: this file belongs to flowing-abyss/obsidian-hybrid-search. 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/flowing-abyss/obsidian-hybrid-search/master/.ai/skills/test-driven-development/SKILL.mdgit clone --depth 1 https://github.com/flowing-abyss/obsidian-hybrid-searchWrote 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/flowing-abyss/obsidian-hybrid-search/test-driven-development)<a href="https://agentmods.dev/skills/flowing-abyss/obsidian-hybrid-search/test-driven-development"><img src="https://agentmods.dev/badge/skills/flowing-abyss/obsidian-hybrid-search/test-driven-development/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/flowing-abyss/obsidian-hybrid-search/test-driven-development"><img src="https://agentmods.dev/badge/skills/flowing-abyss/obsidian-hybrid-search/test-driven-development.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 | $0.00017 | $0.02401 |
| Opus 5.5 | $0.00007 | $0.00960 |
| Sonnet 5.5 | $0.00003 | $0.00480 |
| Haiku 4.5 | $0.00002 | $0.00240 |
Grade A, and why
test-driven-development 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 today.
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.
This is a copy
84% identical to test-driven-development — 81 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 344 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test-Driven Development (TDD)
Overview
Write the test first. Watch it fail. Write minimal code to pass.
Core principle: If you didn't watch the test fail, you don't know if it tests the right thing.
Violating the letter of the rules is violating the spirit of the rules.
When to Use
Always:
- New features
- Bug fixes
- Refactoring
- Behavior changes
Exceptions (ask your human partner):
- Throwaway prototypes
- Generated code
- Configuration files
Thinking "skip TDD just this once"? Stop. That's rationalization.
The Iron Law
NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST
Write code before the test? Delete it. Start over.
No exceptions:
- Don't keep it as "reference"
- Don't "adapt" it while writing tests
- Don't look at it
- Delete means delete
Implement fresh from tests. Period.
Red-Green-Refactor
digraph tdd_cycle {
rankdir=LR;
red [label="RED\nWrite failing test", shape=box, style=filled, fillcolor="#ffcccc"];
verify_red [label="Verify fails\ncorrectly", shape=diamond];
green [label="GREEN\nMinimal code", shape=box, style=filled, fillcolor="#ccffcc"];
verify_green [label="Verify passes\nAll green", shape=diamond];
refactor [label="REFACTOR\nClean up", shape=box, style=filled, fillcolor="#ccccff"];
next [label="Next", shape=ellipse];
red -> verify_red;
verify_red -> green [label="yes"];
verify_red -> red [label="wrong\nfailure"];
green -> verify_green;
verify_green -> refactor [label="yes"];
verify_green -> green [label="no"];
refactor -> verify_green [label="stay\ngreen"];
verify_green -> next;
next -> red;
}
RED - Write Failing Test
Write one minimal test showing what should happen.
const result = await retryOperation(operation);
expect(result).toBe('success'); expect(attempts).toBe(3); });
Clear name, tests real behavior, one thing
</Good>
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- today First seen · 344 lines · 17 tokens per session scan A af9f393d9d1f
test-driven-development is a skill published in the GitHub repository flowing-abyss/obsidian-hybrid-search (113 stars, last pushed today), licensed MIT. It adds 17 tokens to every session and 2,401 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 84% identical to test-driven-development, differing in 81 lines, and is treated as a copy.
Other skills, from other repositories
tdd
A test-first development workflow based on TDD, or test-driven development. It writes a failing test, adds code to make it pass, and then improves the code without changing its behavior.
test-driven-development
(TDD) Use when implementing any feature or bugfix. Apply the Logic Gate to identify what needs tests, then use the Iron Rule for strict test-first development on logic.
test-driven-development
A software-development method called test-driven development, or TDD, where you write a test first, confirm that it fails, then write the smallest implementation that makes it pass.
using-superpowers
An engineering workflow that guides an agent from idea clarification through design, planning, test-driven development, review, verification, and branch cleanup. Test-driven development, or TDD, means writing a failing test before the production code that makes it pass.
test-driven-development
Use when implementing any feature or bugfix, before writing implementation code.
engram-testing-coverage
TDD and coverage standards for Engram. Trigger: When implementing behavior changes in any package.