sdlc-implement

A software-development workflow that implements planned work with Test-Driven Development (TDD), meaning tests are written and used to guide the code.

In plain words
What is it for?
It reviews planning documents, creates test cases from acceptance criteria, and works through tests one priority group at a time.
Why use it?
It turns a user story and implementation plan into checked, incremental work and prevents the process from moving on before each phase passes verification.

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/djscheuf/agentic-dev-ecosystem-template/sdlc-implement
Any agent
npx skills add djscheuf/agentic-dev-ecosystem-template --skill sdlc-implement
Clone the repo
git clone --depth 1 https://github.com/djscheuf/agentic-dev-ecosystem-template

Made for: Claude Code, Codex.

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,226 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 $0.00042 $0.01226
Opus 5 $0.00021 $0.00613
Sonnet 5 $0.00008 $0.00245
Haiku 4.5 $0.00004 $0.00123

Measured 2d ago against content hash 5392c1db7866, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sdlc-implement 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.

.devin/skills/sdlc-implement/SKILL.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SDLC Implement Workflow

Purpose

Implement planned functionality using Test-Driven Development (TDD) methodology by orchestrating skills and subworkflows.

Trigger

  • After Planning an implementation, and before writing any production code

Inputs Required

  • User Story Analysis Document (path to .json file)
  • Implementation Plan for this Workstream (path to .json file)
  • Relevant domain context

CRITICAL RULES

  1. FORBIDDEN: Writing production code directly - You MUST use the designated skills and subworkflows
  2. FORBIDDEN: Skipping skill invocations - Each phase requires specific skill/workflow invocation
  3. FORBIDDEN: Proceeding to next phase until current phase verification passes
  4. ONE priority group at a time - Complete all tests in a priority group before moving to next

Workflow Phases

Phase 0: Review Context

MANDATORY: Read all input documents before proceeding.

Required Inputs:

  • User Story Analysis Document
  • This Workstream's Implementation Plan
  • Existing Test Cases Document (if any from previous run)
  • Relevant domain context (vault pages, existing code)

Actions:

  • Read and understand the requirements
  • Identify what needs to be built
  • Note any dependencies or constraints

Output: Mental model of the task (no files created)


Phase 1: Design Test Cases

MANDATORY: INVOKE the design-test-cases skill.

FORBIDDEN:

  • Write test cases manually
  • Skip this step if test cases already exist (review them instead)

Skill to Invoke: design-test-cases

Expected Output:

  • Test cases JSON file at path specified in sentinel file
  • Sentinel file: .process/design-test-cases.done.json

Verification:

  • Confirm test cases file exists and follows schema
  • Confirm sentinel file exists
  • Review test cases for completeness

Before Proceeding: Ensure verification passes.


Phase 2: Red-Green Loop (Per Priority Group)

CRITICAL: You MUST invoke the /sdlc-tdd subworkflow. DO NOT write tests or implementation code directly.

Read the full file on GitHub · 173 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 · 173 lines · 42 tokens per session scan A 5392c1db7866

Subscribe to this mod's changes

sdlc-implement is a skill published in the GitHub repository djscheuf/agentic-dev-ecosystem-template (12 stars, last pushed 2d ago), licensed MIT. It adds 42 tokens to every session and 1,226 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.

Related

Other skills, from other repositories

agent-integration

Run all three agent integration phases sequentially: research, write-tests, and implement using E2E-first TDD (unit tests written last). For individual phases, use /agent-integration:research, /agent-integration:write-tests, or /agent-integration:implement. Use when the user says "integrate agent", "add agent…

entireio/cli · 89 tokens

engram-testing-coverage

TDD and coverage standards for Engram. Trigger: When implementing behavior changes in any package.

Gentleman-Programming/engram · 25 tokens

code-assist

Guides implementation of code tasks using test-driven development in an Explore, Plan, Code, Commit workflow. Acts as a Technical Implementation Partner and TDD Coach — following existing patterns, avoiding over-engineering, and producing idiomatic, modern code.

mikeyobrien/ralph-orchestrator · 53 tokens

tdd

Test-driven development. Use when the user wants to build features or fix bugs test-first, mentions "red-green-refactor", or wants integration tests.

GreyDGL/PentestGPT · 33 tokens

css-design-tdd

Test-driven CSS design system modifications. Run checks before/after CSS changes to verify token usage, variable definitions, fallbacks, and consistency. Use when modifying CSS tokens, fixing design inconsistencies, or auditing CSS architecture.

xiaolai/vmark · 49 tokens

mobiai-mobile-tdd

You MUST use this before writing any implementation code for a mobile feature, bug fix, refactor, or behavior change. Tests come before implementation — no exceptions.

ArisGuimera/MobiAI-Core · 38 tokens