Borrowing it
Nothing to install: this file belongs to diillson/chatcli. 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/diillson/chatcli/main/.agent/skills/tdd-workflow/SKILL.mdgit clone --depth 1 https://github.com/diillson/chatcliWrote 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/diillson/chatcli/tdd-workflow)<a href="https://agentmods.dev/skills/diillson/chatcli/tdd-workflow"><img src="https://agentmods.dev/badge/skills/diillson/chatcli/tdd-workflow/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/diillson/chatcli/tdd-workflow"><img src="https://agentmods.dev/badge/skills/diillson/chatcli/tdd-workflow.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 | $0.00021 | $0.00724 |
| Opus 5.5 | $0.00008 | $0.00290 |
| Sonnet 5.5 | $0.00004 | $0.00145 |
| Haiku 4.5 | $0.00002 | $0.00072 |
Grade A, and why
tdd-workflow 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 1mo 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.
This is a copy
91% identical to tdd-workflow — 2 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 — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TDD Workflow
Write tests first, code second.
1. The TDD Cycle
🔴 RED → Write failing test
↓
🟢 GREEN → Write minimal code to pass
↓
🔵 REFACTOR → Improve code quality
↓
Repeat...
2. The Three Laws of TDD
- Write production code only to make a failing test pass
- Write only enough test to demonstrate failure
- Write only enough code to make the test pass
3. RED Phase Principles
What to Write
| Focus | Example |
|---|---|
| Behavior | "should add two numbers" |
| Edge cases | "should handle empty input" |
| Error states | "should throw for invalid data" |
RED Phase Rules
- Test must fail first
- Test name describes expected behavior
- One assertion per test (ideally)
4. GREEN Phase Principles
Minimum Code
| Principle | Meaning |
|---|---|
| YAGNI | You Aren't Gonna Need It |
| Simplest thing | Write the minimum to pass |
| No optimization | Just make it work |
GREEN Phase Rules
- Don't write unneeded code
- Don't optimize yet
- Pass the test, nothing more
5. REFACTOR Phase Principles
What to Improve
| Area | Action |
|---|---|
| Duplication | Extract common code |
| Naming | Make intent clear |
| Structure | Improve organization |
| Complexity | Simplify logic |
REFACTOR Rules
- All tests must stay green
- Small incremental changes
- Commit after each refactor
6. AAA Pattern
Every test follows:
| Step | Purpose |
|---|---|
| Arrange | Set up test data |
| Act | Execute code under test |
| Assert | Verify expected outcome |
7. When to Use TDD
| Scenario | TDD Value |
|---|---|
| New feature | High |
| Bug fix | High (write test first) |
| Complex logic | High |
| Exploratory | Low (spike, then TDD) |
| UI layout | Low |
8. Test Prioritization
| Priority | Test Type |
|---|---|
| 1 | Happy path |
| 2 | Error cases |
| 3 | Edge cases |
| 4 | Performance |
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.
- 1mo ago First seen · 150 lines · 21 tokens per session scan A b8fceb81c096
tdd-workflow is a skill published in the GitHub repository diillson/chatcli (93 stars, last pushed today), licensed Apache-2.0. It adds 21 tokens to every session and 724 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 91% identical to tdd-workflow, differing in 2 lines, and is treated as a copy.
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