superplan-tdd

A workflow for test-driven development, or TDD, where a failing test or check is written before production code, followed by implementation and cleanup.

In plain words
What is it for?
Use it for features, bug fixes, and behavior changes with testable requirements.
Why use it?
It makes the intended behavior explicit before coding and provides proof that the change works.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/superplan-md/superplan-plugin/superplan-tdd
Any agent
npx skills add superplan-md/superplan-plugin --skill superplan-tdd
Clone the repo
git clone --depth 1 https://github.com/superplan-md/superplan-plugin

Made for: Claude Code, Codex.

Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 396 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00028 $0.00396
Opus 5 $0.00014 $0.00198
Sonnet 5 $0.00006 $0.00079
Haiku 4.5 $0.00003 $0.00040

Measured 2d ago against content hash 227ebf68dd3f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

superplan-tdd 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.

output/skills/superplan-tdd/SKILL.md · 57 lines

What it actually says

Test-Driven Development

Overview

Write the test or equivalent check first. Watch it fail. Write the minimal code to pass.

Iron Law

No production code without a failing test or failing check first.

If code was written before the proof path, delete the shortcut and start from the failing test.

Hard Gate

Do not treat "I can add tests after" as equivalent. If the proof was not red first, it is not guiding the implementation.

Trigger

Use when:

  • a task has clear enough acceptance criteria that tests or checks can express intended behavior
  • feature work, bugfix work, or behavior change is about to start

Red Green Refactor

  1. Red: write one minimal failing test or check that expresses the contract.
  2. Verify red: confirm it fails for the expected reason.
  3. Green: write the simplest code that passes.
  4. Verify green: rerun the proof and keep other relevant checks green.
  5. Refactor: clean up without changing behavior.

Core Rules

  • prefer the workspace's existing test and verification style
  • derive tests or checks from the task contract and acceptance criteria
  • if the repo lacks strong tests, define the cheapest honest proof before broad code changes
  • keep the verification path aligned with what superplan-review will later judge
  • avoid adding test ceremony that fights the repo's actual setup

Forbidden Behavior

  • writing tests after implementation and calling it equivalent
  • writing vague proofs that do not actually pin the acceptance criteria
  • forcing a test style the repo clearly does not use
  • treating "I wrote a test" as proof the strategy is good

Handoff

After green, execution continues through the normal shaped path and later review still flows through superplan-review.

Files

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.

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. 2d ago First seen · 57 lines · 28 tokens per session scan A 227ebf68dd3f

Subscribe to this mod's changes

superplan-tdd is a skill published in the GitHub repository superplan-md/superplan-plugin (72 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 28 tokens to every session and 396 once invoked, about $0.0001 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.

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