reversa-inspector

Generates parity specs and Gherkin feature files proving legacy-to-new system behavioral equivalence.

1|Updated Jul 10, 2026
One-click install
npx skills add https://github.com/tjsasakifln/extra-cli --skill reversa-inspector-tjsasakifln
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: reversa-inspector
Source: https://github.com/tjsasakifln/extra-cli/tree/main/.agents/skills/reversa-inspector
Command: npx skills add https://github.com/tjsasakifln/extra-cli --skill reversa-inspector-tjsasakifln

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve? When migrating a legacy system to a new architecture, teams need a rigorous way to prove the new system behaves equivalently to the old one. This Skill defines parity validation strategies adapted to the target paradigm and produces traceable Gherkin specifications for critical flows. ## Core Features & Use Cases - Parity Strategy Definition: Selects validation modes (shadow mode, characterization tests, contract tests, data parity) and defines acceptance criteria such as divergence thresholds and observation windows. - Paradigm-Adapted Coverage: Adjusts required test dimensions based on the paradigm transition (e.g., synchronous to event-driven requires idempotency, ordering, and DLQ scenarios). - Gherkin Spec Generation: Produces one .feature file per critical flow with traceability to process flows, target architecture, and business rules, including screen parity scenarios when a UI exists. - Use Case: After the migration team finalizes the target architecture, invoke this Skill to generate parity_specs.md and parity_tests/*.feature files that the coding agent later translates into executable tests. ## Quick Start Run /reversa-inspector after the migration strategy and target architecture are approved to generate the parity specs and Gherkin feature files for all critical flows.

Frequently Asked Questions about reversa-inspector

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I prove a migrated system is equivalent to the legacy system?▼

Define parity specs that select validation modes such as shadow mode, characterization tests, contract tests, and data parity, then set a primary divergence metric and observation window. Generate Gherkin scenarios per critical flow covering positive cases, edge cases, and paradigm-specific concerns like idempotency.

What test scenarios are needed when migrating from synchronous to event-driven architecture?▼

Each critical flow needs at least parity, idempotency, and ordering scenarios, plus dead letter queue behavior when queue failure matters. The parity-coverage matrix defines minimum scenario sets per paradigm transition, including saga compensation for distributed transactions.

Can the generated Gherkin feature files be executed directly as tests?▼

No, the .feature files are specifications, not executable tests. They contain traceability metadata and scenario definitions that a coding agent or developer translates into the appropriate test framework for the target stack.

What happens to screen parity when the legacy system has no UI?▼

When the screen modernization decision is in skipped status, visual parity is ignored entirely and no paridade-visual scenarios are created. The parity specs document that the system has no UI.

What are typical acceptance criteria for parity in regulated systems?▼

Fiscal or regulatory systems typically require functional divergence below 0.01% over 60 days with zero divergence in regulated fields. Financial systems target monetary divergence below 0.001% with zero divergence in totalizers.