implement

name	implement
description	Implement features using Test-Driven Development (TDD). Executes red-green-refactor cycle, uses bmad-commands for file operations and testing, verifies acceptance criteria. This skill should be used when implementing new features or functionality from task specifications with test coverage.
acceptance	[{"tests_passing":"All tests must pass"},{"coverage_threshold":"Test coverage >= 80%"},{"no_syntax_errors":"Code must have no syntax errors"},{"task_spec_loaded":"Task specification must be successfully loaded"},{"all_requirements_met":"All acceptance criteria from task spec must be met"}]
inputs	{"task_id":{"type":"string","required":true,"description":"Task identifier (e.g., task-auth-002)","validation":"Must match pattern: task-{component}-{number}"}}
outputs	{"implementation_complete":{"type":"boolean","description":"Whether implementation is complete and meets all criteria"},"test_coverage_percent":{"type":"number","description":"Test coverage percentage achieved"},"files_modified":{"type":"array","description":"List of files created or modified"},"tests_passed":{"type":"boolean","description":"Whether all tests passed"}}
telemetry	{"emit":"skill.implement.completed","track":["task_id","test_coverage_percent","duration_ms","files_modified_count","tests_total","tests_passed","tests_failed"]}

Implement Feature with TDD

Overview

Implement features following strict Test-Driven Development workflow. Uses bmad-commands for deterministic file and test operations, ensures acceptance criteria are met through automated verification.

TDD Cycle:

1. RED: Write failing tests
2. GREEN: Implement code to pass tests
3. REFACTOR: Improve code while keeping tests green

Prerequisites

• Task specification exists at workspace/tasks/{task_id}.md
• bmad-commands skill available at .claude/skills/bmad-commands/
• Development environment configured
• Test framework installed (Jest or Pytest)

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Workflow

Step 0: Load Task Specification

Action: Use read_file command to load task spec.

python .claude/skills/bmad-commands/scripts/read_file.py \
  --path workspace/tasks/{task_id}.md \
  --output json

Parse Response:

• Extract outputs.content for task specification
• Verify success == true
• Parse task spec sections:
  • Objective
  • Acceptance Criteria
  • Technical Specifications
  • Required Files

Required Sections in Task Spec:

## Objective
[What to build]

## Acceptance Criteria
1. [Testable requirement 1]
2. [Testable requirement 2]

## Technical Specifications
- API endpoints
- Data models
- Dependencies
- File locations

## Required Files
- src/path/to/implementation.ts
- tests/path/to/tests.test.ts

If task spec not found or invalid:

• Return error with message
• Suggest creating task spec first
• Halt implementation

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Step 0.5: Check for External Packages and Fetch Documentation