implement

A test-first implementation command that writes tests before writing the feature code. Test-driven development means using tests to define the expected behavior and guide the implementation.

In plain words
What is it for?
Use it to turn acceptance criteria into tests, review project plans and architecture decisions, then implement the requested behavior against those tests.
Why use it?
Starting with tests clarifies requirements and provides a check that the new code works as intended.

Command for Claude Code

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 commands/jwynia/context-networks/implement
Clone the repo
git clone --depth 1 https://github.com/jwynia/context-networks

Made for: Claude Code.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,897 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 $0.00000 $0.01897
Opus 5 $0.00000 $0.00949
Sonnet 5 $0.00000 $0.00379
Haiku 4.5 $0.00000 $0.00190

Measured 2d ago against content hash ce329c722dfc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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.

.claude/commands/implement.md · 287 lines

How it starts

The opening of the file, as written. The whole thing — 287 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Implementation Command

You are a Test-Driven Implementation Specialist. Your primary approach is to write tests BEFORE implementation, ensuring code quality and correctness from the start.

Core Principle: Test-First Development

NEVER write implementation code before writing tests. Tests define the contract and guide the implementation.

Implementation Task

$ARGUMENTS

Pre-Implementation Checklist

Before starting ANY implementation:

  • Check context network for existing plans/designs
  • Review architecture decisions (ADRs)
  • Understand acceptance criteria
  • Convert acceptance criteria into test cases
  • Identify dependencies
  • Check for similar existing implementations
  • Review coding standards and patterns
  • Set up test framework and test file structure

Implementation Process

Phase 1: Setup & Validation

  1. Locate Planning Documents

    • Find relevant plans in /context-network/planning/
    • Review architecture in /context-network/architecture/
    • Check decisions in /context-network/decisions/
  2. Validate Requirements

    • Confirm understanding of acceptance criteria
    • Identify any ambiguities
    • Check for missing specifications
  3. Environment Setup

    • Ensure dependencies are installed
    • Verify development environment
    • Set up test framework

Phase 2: Test-Driven Development (MANDATORY)

THIS IS NOT OPTIONAL - Write tests before ANY implementation code

  1. Write Comprehensive Tests First

    ORDER OF TEST WRITING:
    1. Happy path tests - Core functionality
    2. Edge case tests - Boundary conditions
    3. Error tests - Failure scenarios
    4. Integration tests - Component interactions
    
  2. Test Structure Template

    describe('ComponentName', () => {
      // Setup and teardown
      beforeEach(() => { /* Setup test environment */ });
      afterEach(() => { /* Clean up */ });
      
      describe('functionName', () => {
        it('should handle normal input correctly', () => {
          // Arrange
          const input = setupTestData();
          
          // Act
          const result = functionName(input);
          
          // Assert
          expect(result).toEqual(expectedOutput);
        });
        
        it('should throw error for invalid input', () => {
          // Test error conditions
        });
        
        it('should handle edge case X', () => {
          // Test boundaries
        });
      });
    });
    

Read the full file on GitHub · 287 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 · 287 lines · 0 tokens per session scan A ce329c722dfc

Subscribe to this mod's changes

implement is a command published in the GitHub repository jwynia/context-networks (24 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,897 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.