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 rules/krivoox/agent-stack-template/tdd-domaingit clone --depth 1 https://github.com/krivoox/agent-stack-templateWhat 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 | $0.00000 | $0.00281 |
| Opus 5 | $0.00000 | $0.00140 |
| Sonnet 5 | $0.00000 | $0.00056 |
| Haiku 4.5 | $0.00000 | $0.00028 |
Grade A, and why
tdd-domain 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.
What it actually says
TDD — business logic
Red → green → refactor. The test comes first, and it must fail for the right reason before you write the implementation.
Tested
src/domain/**src/features/*/domain/**- Any pure calculation or invariant
Not tested
React components, styles, layout, snapshots. A snapshot test of a component is a maintenance cost with no signal — do not add one, even "for coverage".
Writing the test
- One behaviour per
it, named as the rule it protects, not as the function it calls:"rejects a duplicate name regardless of casing", not"works". - Assert on the error type from
src/domain/errors.ts, not on the message — copy changes, semantics do not. - Cover the boundary, not just the happy path: empty input, the limit itself, one past the limit, and the case that must be rejected.
- No mocks. If a rule needs the clock, a random value or a database row, that input is a parameter — this is what keeps the domain testable.
Full workflow
docs/tdd-workflow.md.
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 · 37 lines · 0 tokens per session scan A 53e481160794
tdd-domain is a cursor rule published in the GitHub repository krivoox/agent-stack-template (31 stars, last pushed 12d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 281 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 2026-08-30.
Other cursor rules, from other repositories
tdd-skill
TDD follows Kent Beck's short feedback loop. With an AI agent, the Green step is more deliberate: do not ask for intentionally dirty code and plan a cleanup pass. Ask for the smallest production-quality implementation that satisfies the test, then reserve deeper design changes for a separate refining refactor.
us-prioritization
Cursor rule "us-prioritization" from KaelSensei/MagicAIBuilder, covering set to false so it only applies when relevant, user story prioritization & weighting, story points (planning poker), what it is and why fibonacci?.
documentation
CRITICAL: Update documentation automatically after every code change.
technical-stack
These rules guide the AI assistant when generating or modifying code in MagicTheOfflining, a React Native offline MTG deck viewer.
version-management
Automatically commit and push changes after completing any feature, bug fix, or significant addition.
general-principles
These rules define the core philosophy and mental model for MagicTheOfflining - a personal, offline-first React Native app for managing Magic: The Gathering Commander decks.