ba-mode-reverse-engineer

A business-analysis workflow for reconstructing software requirements from an existing codebase when no approved requirements document exists. It uses archaeology reports and an extracted architecture document, then pauses for human confirmation.

In plain words
What is it for?
Use it during brownfield onboarding to derive a draft software requirements document from code, architecture notes, archaeology reports, and API contracts.
Why use it?
It provides a way to document what an existing system appears to do without silently treating those findings as confirmed requirements.

Skill for Claude CodeCodex

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 skills/evolplus/talos/ba-mode-reverse-engineer
Any agent
npx skills add evolplus/talos --skill ba-mode-reverse-engineer
Clone the repo
git clone --depth 1 https://github.com/evolplus/talos

Made for: Claude Code, Codex.

Per session 89 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,866 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 $0.00089 $0.04866
Opus 5 $0.00044 $0.02433
Sonnet 5 $0.00018 $0.00973
Haiku 4.5 $0.00009 $0.00487

Measured 2d ago against content hash 0318f54a3fc3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ba-mode-reverse-engineer 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.

skills/ba-mode-reverse-engineer/SKILL.md · 160 lines

How it starts

The opening of the file, as written. The whole thing — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.

BA Mode E — reverse-engineer-from-code (brownfield Stage 3)

When to use

You are the BA and Shape Detection selected Mode E: the codebase exists, no SRS has been authored, and the Codebase Archaeologist (Stage 1) + SA extract (Stage 2) have produced docs/archaeology-reports/ and a provisional docs/architecture.md. Derive a kit-shape SRS, then HALT for the Stage 4 human-confirmation gate (never auto-approve).

Phase 1.E — Mode reverse-engineer-from-code setup (brownfield onboarding Stage 3)

The codebase exists; no SRS has been authored yet (or only a placeholder exists). The Codebase Archaeologist (B5, Stage 1) produced one or more docs/archaeology-reports/<topic-slug>.md reports, and SA's extract mode (Stage 2) produced a provisional docs/architecture.md flagged Source: extracted. Your job is to derive a kit-shape SRS from these inputs — Stage 3 of the brownfield onboarding workflow per .claude/rules/brownfield-onboarding.md §12.

E1. Read all inputs.

  • Every docs/archaeology-reports/<topic-slug>.md (Stage 1 output).
  • docs/architecture.md from SA extract mode (Stage 2 output; Source: extracted per section).
  • Every docs/api-contracts/* file produced by SA extract mode with Status: Extracted.
  • Any pre-existing non-kit docs the archaeology report cataloged (READMEs, Confluence pages, prior ADRs).
  • User-supplied context from the dispatch input (named PM, named Eng Lead, business intent the team can articulate even if it's not in code).
  • Frontend framework evidence from the archaeology report (## Frontend Framework Evidence if present, Service / Module Inventory Stack column otherwise) and architecture container stack fields.
  • Backend track/framework evidence from the archaeology report (## Backend Framework Evidence if present, Service / Module Inventory Stack column otherwise), public API/event/worker evidence, and architecture container stack fields.
  • Route/dependency/message evidence from the archaeology report: ## Service Boundary & Entry Point Map, ## Route / RPC / Job Trace Matrix, ## Dependency & Call Graph (C3), ## Message Broker / Consumer Logic, and ## API / Message Spec Candidates.

Read the full file on GitHub · 160 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 · 160 lines · 89 tokens per session scan A 0318f54a3fc3

Subscribe to this mod's changes

ba-mode-reverse-engineer is a skill published in the GitHub repository evolplus/talos (8 stars, last pushed 28d ago), licensed Apache-2.0. It adds 89 tokens to every session and 4,866 once invoked, about $0.0004 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 2026-08-31.

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