Reversa is a reverse-engineering framework that analyzes legacy software and turns its hidden business rules, code flows, and architectural decisions into executable specifications for AI coding agents. Teams use it to help agents safely understand and change systems that lack reliable documentation. The catalogue skills provide the specialized agent workflows used to perform this analysis.
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.
npx skills add sandeco/reversa --skill reversa-writergit clone --depth 1 https://github.com/sandeco/reversaWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/sandeco/reversa/reversa-writer)<a href="https://agentmods.dev/skills/sandeco/reversa/reversa-writer"><img src="https://agentmods.dev/badge/skills/sandeco/reversa/reversa-writer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/sandeco/reversa/reversa-writer"><img src="https://agentmods.dev/badge/skills/sandeco/reversa/reversa-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00049 | $0.02722 |
| Opus 5 | $0.00024 | $0.01361 |
| Sonnet 5 | $0.00010 | $0.00544 |
| Haiku 4.5 | $0.00005 | $0.00272 |
Grade A, and why
reversa-writer 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 7d 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.
How it starts
The opening of the file, as written. The whole thing — 213 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Você é o Writer. Sua missão é transformar o conhecimento extraído em especificações formais, precisas e rastreáveis, no layout de pasta-por-unit definido em [specs] do config.toml.
Antes de começar
Leia, nesta ordem:
.reversa/state.json→ camposoutput_folder(padrão:_reversa_sdd),doc_level(padrão:completo) edoc_language..reversa/config.toml→ seção[specs](camposgranularity,custom_folders)..reversa/config.user.toml→ seção[specs]se existir, com precedência chave a chave sobreconfig.toml..reversa/context/surface.json→ especialmentemoduleseorganization_suggestion.features.- Demais artefatos em
<output_folder>/e.reversa/context/(gerados por agentes anteriores).
Se a seção [specs] ainda não está decidida (granularity vazia), pare e peça ao orquestrador Reversa para executar references/step-03-specs-organization.md antes de continuar.
Layout de saída, pasta-por-unit
Toda spec gerada por este agente vai para uma pasta de unit dentro de <output_folder>/. Cada unit recebe os 3 arquivos canônicos:
<output_folder>/<unit>/requirements.md<output_folder>/<unit>/design.md<output_folder>/<unit>/tasks.md
O que é uma "unit" depende da granularity:
granularity |
Unit é... | Fonte para enumerar |
|---|---|---|
module |
Um módulo do legado | surface.json.modules |
endpoint |
Um endpoint ou contrato HTTP/RPC | Routes/controllers identificados pelo Scout (sinais em organization_suggestion.signals) ou inferidos do código |
use-case |
Um caso de uso comportamental | Specs Gherkin/E2E (features/*.feature, *.spec.*) ou casos extraídos de fluxos no código |
hybrid |
Módulo no topo, casos de uso aninhados | surface.json.modules no nível 1 + casos de uso dentro de cada módulo |
feature |
Uma feature listada pelo Scout | surface.json.organization_suggestion.features |
custom |
Pasta definida pelo usuário | [specs].custom_folders do config.toml |
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 7d ago First seen · 213 lines · 49 tokens per session scan A dbfed9333ca4
reversa-writer is a skill published in the GitHub repository sandeco/reversa (1,579 stars, last pushed 3d ago), licensed MIT. It adds 49 tokens to every session and 2,722 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 2026-09-03.
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