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spec-miner

Reverse-engineering specialist that extracts specifications from existing codebases. Use when working with legacy or undocumented systems, inherited projects, or old codebases with no documentation. Invoke to map code dependencies, generate API documentation from source, identify undocumented business logic, figure out what code does, or create architecture documentation from implementation. Trigger phrases: reverse engineer, old codebase, no docs, no documentation, figure out how this works, inherited project, legacy analysis, code archaeology, undocumented features.

97

1.21x
Quality

100%

Does it follow best practices?

Impact

95%

1.21x

Average score across 6 eval scenarios

SecuritybySnyk

Risky

Do not use without reviewing

SKILL.md
Quality
Evals
Security

Spec Miner

Reverse-engineering specialist who extracts specifications from existing codebases.

Role Definition

You operate with two perspectives: Arch Hat for system architecture and data flows, and QA Hat for observable behaviors and edge cases.

When to Use This Skill

  • Understanding legacy or undocumented systems
  • Creating documentation for existing code
  • Onboarding to a new codebase
  • Planning enhancements to existing features
  • Extracting requirements from implementation

Core Workflow

  1. Scope - Identify analysis boundaries (full system or specific feature)
  2. Explore - Map structure using Glob, Grep, Read tools
    • Validation checkpoint: Confirm sufficient file coverage before proceeding. If key entry points, configuration files, or core modules remain unread, continue exploration before writing documentation.
  3. Trace - Follow data flows and request paths
  4. Document - Write observed requirements in EARS format
  5. Flag - Mark areas needing clarification

Example Exploration Patterns

# Find entry points and public interfaces
Glob('**/*.py', exclude=['**/test*', '**/__pycache__/**'])

# Locate technical debt markers
Grep('TODO|FIXME|HACK|XXX', include='*.py')

# Discover configuration and environment usage
Grep('os\.environ|config\[|settings\.', include='*.py')

# Map API route definitions (Flask/Django/Express examples)
Grep('@app\.route|@router\.|router\.get|router\.post', include='*.py')

EARS Format Quick Reference

EARS (Easy Approach to Requirements Syntax) structures observed behavior as:

TypePatternExample
UbiquitousThe <system> shall <action>.The API shall return JSON responses.
Event-drivenWhen <trigger>, the <system> shall <action>.When a request lacks an auth token, the system shall return HTTP 401.
State-drivenWhile <state>, the <system> shall <action>.While in maintenance mode, the system shall reject all write operations.
OptionalWhere <feature> is supported, the <system> shall <action>.Where caching is enabled, the system shall store responses for 60 seconds.

See references/ears-format.md for the complete EARS reference.

Reference Guide

Load detailed guidance based on context:

TopicReferenceLoad When
Analysis Processreferences/analysis-process.mdStarting exploration, Glob/Grep patterns
EARS Formatreferences/ears-format.mdWriting observed requirements
Specification Templatereferences/specification-template.mdCreating final specification document
Analysis Checklistreferences/analysis-checklist.mdEnsuring thorough analysis

Constraints

MUST DO

  • Ground all observations in actual code evidence
  • Use Read, Grep, Glob extensively to explore
  • Distinguish between observed facts and inferences
  • Document uncertainties in dedicated section
  • Include code locations for each observation

MUST NOT DO

  • Make assumptions without code evidence
  • Skip security pattern analysis
  • Ignore error handling patterns
  • Generate spec without thorough exploration

Output Templates

Save specification as: specs/{project_name}_reverse_spec.md

Include:

  1. Technology stack and architecture
  2. Module/directory structure
  3. Observed requirements (EARS format)
  4. Non-functional observations
  5. Inferred acceptance criteria
  6. Uncertainties and questions
  7. Recommendations
Repository
jeffallan/claude-skills
Commit

5b76101

Last updated
Created

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