tdd-plan

tdd-plan is a skill for Claude Code from morodomi/tdd-skills. It costs 37 tokens per session (874 once invoked), scanned A, original, MIT.

A planning step in TDD, or test-driven development, a method where tests are written to guide implementation. It reads the current project cycle document, plans the work, updates the plan, and creates a checklist of tests.

In plain words
What is it for?
Use it to prepare a feature plan, review project risks and documentation, discuss architecture and quality requirements, and list normal, boundary, edge, error, permission, external-service, and security cases.
Why use it?
It helps define the design, risks, dependencies, and expected behavior before code is written. This step does not create implementation code or test code.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the tdd-core plugin — 13 skills, 14 agents shipped together

Good fit Use it to prepare a feature plan, review project risks and documentation, discuss architecture and quality requirements, and list normal, boundary, edge, error, permission, external-service, and security cases.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/morodomi/tdd-skills/tdd-plan
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.

Any agent
npx skills add morodomi/tdd-skills --skill tdd-plan
Clone the repo
git clone --depth 1 https://github.com/morodomi/tdd-skills

Made for: Claude Code.

Or install tdd-core, the plugin that ships this one along with the rest of its 13 skills, 14 agents.

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 tdd-plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/morodomi/tdd-skills/tdd-plan/github.svg)](https://agentmods.dev/skills/morodomi/tdd-skills/tdd-plan)
Your own site
<a href="https://agentmods.dev/skills/morodomi/tdd-skills/tdd-plan"><img src="https://agentmods.dev/badge/skills/morodomi/tdd-skills/tdd-plan/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.

agentmods 80×15 button for tdd-plan

Your own site · 80×15
<a href="https://agentmods.dev/skills/morodomi/tdd-skills/tdd-plan"><img src="https://agentmods.dev/badge/skills/morodomi/tdd-skills/tdd-plan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 874 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original 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 5.1 $0.00037 $0.00874
Opus 5 $0.00018 $0.00437
Sonnet 5 $0.00007 $0.00175
Haiku 4.5 $0.00004 $0.00087

Measured 10d ago against content hash 051dacdb271f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

tdd-plan 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 10d 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.

plugins/tdd-core/skills/tdd-plan/SKILL.md · 99 lines

What it actually says

TDD PLAN Phase

実装計画を作成し、Cycle docのPLANセクションを更新する。

Progress Checklist

PLAN Progress:
- [ ] Cycle doc確認 → リスク確認 → ドキュメント確認
- [ ] 対話 → PLAN更新 → Test List作成
- [ ] plan-review自動実行

禁止事項

  • 実装コード作成(GREENで行う)
  • テストコード作成(REDで行う)

Workflow

Step 1: Cycle doc確認

ls -t docs/cycles/*.md 2>/dev/null | head -1

Environmentセクションでバージョン情報を把握。

Step 1.5: リスクスコア確認

Cycle docの Risk: [スコア] ([判定]) を読み取り、設計深度を決定:

スコア 判定 設計深度
0-29 PASS 簡易設計(Test List中心、対話省略可)
30-59 WARN 標準設計(現行通り)
60-100 BLOCK 詳細設計(reference.md参照)

Riskフィールドなし → WARN(標準設計)として扱う。

Step 2: 最新ドキュメント確認(必要な場合)

メジャーバージョンや破壊的変更が疑われる場合、WebSearch/WebFetchで確認。

Step 3: 実装計画の対話

アーキテクチャ、依存関係、品質基準をユーザーに確認。

Step 4: PLANセクション更新

背景・設計方針・ファイル構成をCycle docに追記。

Step 5: Test List作成

タスク粒度: 各タスクは2-5分で完了する1アクション

5分を超えそうなタスクは分割する。詳細: reference.md

カテゴリ 必須
正常系
境界値
エッジケース
異常系
権限 △ 認証機能時
外部依存 △ API/DB連携時
セキュリティ △ 入力処理時

目安: 機能1つにつき5-10ケース(各2-5分)

異常系は エラーメッセージ設計 を参照。

## Test List

### TODO
- [ ] TC-01: [正常系]
- [ ] TC-02: [境界値]
- [ ] TC-03: [エッジケース]
- [ ] TC-04: [異常系]

Step 5.5: クロスレイヤー検出(tdd-parallel 提案)

CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS 有効時、複数レイヤー検出で tdd-parallel を提案。詳細: reference.md

Step 6: plan-review自動実行

Test List作成後、Skill(tdd-core:plan-review) を実行。plan-reviewがRED以降を制御。

Reference

Files

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.

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. 10d ago First seen · 99 lines · 37 tokens per session scan A 051dacdb271f

Subscribe to this mod's changes

tdd-plan is a skill published in the GitHub repository morodomi/tdd-skills (8 stars, last pushed 6mo ago), licensed MIT. It adds 37 tokens to every session and 874 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 2026-08-31.