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.
npx agentmods add skills/dean0x/devflow/test-driven-developmentnpx skills add dean0x/devflow --skill test-driven-developmentgit clone --depth 1 https://github.com/dean0x/devflowWhat 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 | $0.00032 | $0.02192 |
| Opus 5 | $0.00016 | $0.01096 |
| Sonnet 5 | $0.00006 | $0.00438 |
| Haiku 4.5 | $0.00003 | $0.00219 |
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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 198 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test-Driven Development
Enforce the RED-GREEN-REFACTOR cycle for all implementation work. Tests define the design. Code satisfies the tests. Refactoring improves the design without changing behavior.
Iron Law
TESTS FIRST, ALWAYS
Write the failing test before the production code. No exceptions. If you catch yourself writing production code without a failing test, stop immediately, delete the production code, write the test, watch it fail, then write the minimum code to make it pass. The test IS the specification.
The Cycle
Step 1: RED — Write a Failing Test
Write a test that describes the behavior you want. Run it. Watch it fail. The failure message IS your specification.
Describe what the code SHOULD do, not how it does it.
One behavior per test. One assertion per test (ideally).
Name tests as sentences: "returns error when email is invalid"
Checkpoint: The test MUST fail before proceeding. A test that passes immediately proves nothing.
Step 2: GREEN — Write Minimum Code to Pass
Write the simplest production code that makes the failing test pass. No more, no less.
Hardcode first if that's simplest. Generalize when the next test forces it.
Don't write code "you'll need later." Write code the test demands NOW.
Don't optimize. Don't refactor. Don't clean up. Just pass the test.
Checkpoint: All tests pass. If any test fails, fix it before moving on.
Step 3: REFACTOR — Improve Without Changing Behavior
Now clean up. Extract helpers, rename variables, simplify logic. Tests stay green throughout.
Run tests after every refactoring step.
If a test breaks during refactor, undo immediately — you changed behavior.
Apply DRY, extract patterns, improve readability.
Checkpoint: All tests still pass. Code is clean. Repeat from Step 1 for next behavior.
Cycle Verification
After each RED-GREEN-REFACTOR cycle, ALL must hold:
- Test existed BEFORE production code (not concurrent, not after)
- Test failed for the RIGHT reason (expected behavior absent, not syntax/import error)
- Production code is minimal — no speculative additions beyond what the test demands
- ALL tests pass, not just the new one
- Refactoring happened in Step 3 (or code is already clean — state explicitly)
- No untested production code remains
What ships with it
1 file 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.
- 2d ago First seen · 198 lines · 32 tokens per session scan A d841ab907be7
test-driven-development is a skill published in the GitHub repository dean0x/devflow (19 stars, last pushed 2d ago), licensed MIT. It adds 32 tokens to every session and 2,192 once invoked, about $0.0002 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.
Other skills, from other repositories
data-engineering
Skill "data-engineering" from fengshao1227/ccg-workflow, covering 数据工程域 · data engineering, 域概览, 数据管道编排, 框架对比 and airflow 核心模式.
verify-change
变更校验关卡。分析代码变更，检测文档同步状态，评估变更影响范围。当用户提到变更检查、文档同步、代码审查、提交前检查、diff分析时使用。在设计级变更、重构完成时自动触发。.
verify-security
安全校验关卡。自动扫描代码安全漏洞，检测危险模式，确保安全决策有文档记录。当用户提到安全扫描、漏洞检测、安全审计、代码安全、OWASP、注入检测、敏感信息泄露时使用。在新建模块、安全相关变更、攻防任务、重构完成时自动触发。.
liquid-glass
Apple Liquid Glass design system. Use when building UI with translucent, depth-aware glass morphism following Apple's design language. Provides CSS tokens, component patterns, dark/light mode, and animation specs.
gen-docs
文档生成器。自动分析模块结构，生成 README.md 和 DESIGN.md 骨架。当用户提到生成文档、创建README、创建DESIGN、文档骨架、文档模板时使用。在新建模块开始时自动触发。.
verify-module
模块完整性校验关卡。扫描目录结构、检测缺失文档、验证代码与文档同步。当用户提到模块校验、文档检查、结构完整性、README检查、DESIGN检查时使用。在新建模块完成时自动触发。.