tdd

A strict test-driven development workflow for behavior changes. Test-driven development, or TDD, means writing a failing test before writing the production code that should make it pass.

In plain words
What is it for?
Use it for new features, bug fixes, and refactoring by moving through failing test, passing test, cleanup, and completion stages.
Why use it?
It verifies the intended behavior first and keeps implementation changes focused on a demonstrated requirement.

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/datit309/supergraph/tdd
Any agent
npx skills add datit309/supergraph --skill tdd
Clone the repo
git clone --depth 1 https://github.com/datit309/supergraph

Made for: Claude Code, Codex.

Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,190 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 $0.00029 $0.01190
Opus 5 $0.00015 $0.00595
Sonnet 5 $0.00006 $0.00238
Haiku 4.5 $0.00003 $0.00119

Measured 2d ago against content hash 1717b2cbf382, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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.

plugins/supergraph/skills/tdd/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/supergraph:tdd

Requires healthy index_status for CBM_PROJECT (see references/codebase-memory-contract.md with codebase-memory-mcp); if stale/degraded → index_repository before graph calls.

Strict TDD for features, bug fixes, refactors.

Iron Law: NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST

Delete means delete: Production code written before verified failing test → delete and restart from RED.

When

Full TDD: new features, behavior changes, refactoring. Fast TDD: bug fixes (add regression test → RED verify → minimal fix). Ask to skip: config-only, generated code, throwaway prototype, docs-only.

State Machine (in order, never skip)

needs_testred_verifiedgreen_verifiedrefactor_allowedcomplete

Steps

0. Announce

"🔴 /supergraph:tdd — TDD: [full|fast] for [behavior]..."

1. Identify One Behavior

Behavior: [single externally visible behavior]
Test file: [path] | Test name: [name]
Command: [focused test command]
Expected RED: [why it should fail before implementation]

One behavior per test. Public behavior, not internals. Real code over mocks.

2. 🔴 RED — Write + Verify in One Round

Write one failing test, then run immediately:

<write test> && $TEST_CMD <focused command>

Valid 🔴 RED: fails for the expected missing behavior, not syntax/import/typo.

Record evidence:

## TDD Evidence — 🔴 RED
- 🔴 RED: `[command]` → FAIL ([expected missing behavior])

Serena diagnostics (optional): See serena/SKILL.md:Setupget_diagnostics_for_file before/after GREEN; use replace_symbol_body/rename_symbol over raw edits. Skip if SERENA_ACTIVE=false or unavailable.

Invalid RED → fix test setup, don't write production code yet.

3. 🟢 GREEN — Minimal Implementation

Write only enough code to pass the test. No abstractions, no cleanup, no extra features.

Delete any production code written before RED.

4. 🟢 GREEN Verify

Run focused test → broader suite:

## TDD Evidence — 🟢 GREEN
- 🟢 GREEN: `[command]` → PASS
- Suite: PASS

Read the full file on GitHub · 152 lines

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 · 152 lines · 29 tokens per session scan A 1717b2cbf382

Subscribe to this mod's changes

tdd is a skill published in the GitHub repository datit309/supergraph (21 stars, last pushed 4d ago), licensed MIT. It adds 29 tokens to every session and 1,190 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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