# Rea Analysis > Reverse engineer apps with REA. Explore how features work, then build a version tailored to your project. - **Type:** Skill - **Install:** `agentstack add skill-morluto-rea-rea-analysis` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [morluto](https://agentstack.voostack.com/s/morluto) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [morluto](https://github.com/morluto) - **Source:** https://github.com/morluto/rea/tree/main/skills/rea-analysis ## Install ```sh agentstack add skill-morluto-rea-rea-analysis ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # REA Use REA when the user wants to understand how an app or feature works, compare app versions, decompile code, or build a similar feature. ## Understand the request Identify the app and what the user wants to understand or build. Do not ask for information they already provided. If the app is missing, ask which app they want to reverse engineer. If the app is known but the goal is unclear, ask what they want to understand or build, and offer to start with an overview. Never require the user to supply a program path, address, architecture, or reverse-engineering terminology. Notes is only a documentation example. Never select an app unless the user names it or confirms it. ## Ensure REA is ready 1. Run `npx -y rea-agents doctor`. 2. If setup is needed, tell the user REA needs to install its local binary-analysis tools. Do not lead with implementation details or assume the user knows reverse-engineering products. 3. Before installing external software, obtain approval and identify what will be installed. If deeper analysis needs Hopper, describe it as REA's local analysis engine and note that it is a separate Mac app with its own license. Then run `npx -y rea-agents setup --yes`. 4. If macOS or an installer requests human input, tell the user exactly what needs attention. After they finish, rerun setup and doctor. 5. If setup registers a new MCP server, tell the user to restart their coding agent to load all REA tools. Direct CLI commands remain available before restart. ## Locate the app Accept a human-readable app name. Search macOS application locations and system metadata. If one clear match is found, continue without asking for a path. If several apps match, show their names and locations and ask which one the user means. If none match, ask where the app is installed. REA accepts a `.app` bundle directly. Do not expose its internal `Contents/MacOS` path unless it helps explain an error. ## Investigate Briefly tell the user what you will investigate. Open the app with `open_binary`, begin with `binary_overview`, and narrow the investigation around the requested feature. Use decompilation, strings, names, callers, callees, and cross-references as needed. For applications, ZIP/APK/IPA packages, or Electron ASAR archives, call `inventory_artifact` before extraction. Follow its deterministic occurrence pages and cite graph manifest IDs. `extract_artifact` requires explicit user approval, an absent absolute output root, and selected occurrence IDs; never extract every entry implicitly. Symlinks and encrypted entries are inventory facts, not extractable files. Nested containers require a separate deliberate inventory step. Explain conclusions in plain language. Point to the relevant decompiled code, strings, names, and connections so the user can see how the explanation was reached. Do not claim to recover original source code or automatically clone an application. Search uses bounded deterministic pages. Prefer literal mode; use regex mode only when regex semantics are needed, and continue from `next_offset` while `has_more` is true. Treat nullable permissions and explicit unavailable metadata as unknown, never as `false`. Every successful analysis result is Evidence v2. Cite evidence IDs and preserve limitations and residual unknowns. Process capture is disabled by default, requires per-call approval plus operator policy, and uses host networking only when the operator explicitly permits it. It is behavioral evidence, not a security sandbox. Do not let unanswered questions disappear. Use `record_unknown` only with explicit approval, attach supporting and contradicting evidence IDs, and record the authority/environment still required. Use `update_unknown` with the current `expected_revision`; stale updates must be re-read, not retried blindly. A verified resolution needs qualifying observed evidence. Inference, withdrawn, and out-of-scope dispositions are never substitutes for observed behavior. Set `unknown_registry_approved: true` on `trace_feature` or `capture_process_scenario` only when the user approves durable automatic recording of their bounded residuals. The same flag on a direct operation records typed provider unavailability, and on `compare_process_captures` records an observed disagreement as a contradiction. Use `compare_artifacts` with one record or bounded arrays of `inventory_artifact` Evidence pages per side. Pages must share one manifest; collect all node, occurrence, and edge pages for exhaustive comparison. It compares stable occurrence paths, content, metadata, and graph relations, cites both evidence sets on every delta, and paginates changes. Incomplete inventories are truncated or unknown, never equivalent. Set `unknown_registry_approved: true` only with approval to preserve the disagreement or missing evidence as a residual unknown. Use `compare_functions` with explicit `analyze_function` Evidence page sets; it does not perform fuzzy whole-binary matching. Collect every pseudocode, assembly, collection, and CFG page when exhaustive comparison matters. Absolute addresses are volatile only in CFG topology; pseudocode constants are never stripped. Omitted assembly, truncated scans, unavailable reference kinds, and cross-provider text remain unknown rather than equal. Use `compare_bundles` for canonical Evidence v2 bundle membership and residual-unknown history changes. Pair cross-version observations explicitly; the tool never guesses record identity. One-sided records prove only bundle inclusion or omission, not behavioral absence. Use the returned canonical bundle digests to anchor paginated reports. Use `find_changed_behavior` to combine existing comparison Evidence. Runtime process differences are observed changes; artifact and function differences remain static candidates, not causal proof. Supply complete comparison pages. Use `build_call_path` with explicit `analyze_function` Evidence groups from one artifact and provider. Select endpoints by exact address. Missing dossiers, incomplete callee pages, or a depth frontier make absence unknown; found paths remain valid and cite each contributing dossier. Use `correlate_static_and_runtime` only with explicit mappings between exact static and runtime comparison findings. A matching pattern is a hypothesis, never proof of causality. Declare side alignment; unmapped similarities are not correlated. Use `verify_reconstruction` with a finite typed specification and canonical Evidence bundle. Pass means all declared claims passed with comparable authority, not global implementation equivalence. Missing, limited, active- unknown, or incompatible evidence stays unknown; observed differences fail. ## Build When requested, use normal coding tools to build a version suited to the user's project, stack, interface, and requirements. Keep the implementation tied to what the investigation established, and distinguish observed behavior from assumptions or design choices. ## Human input and cleanup Hopper or macOS may show a window that needs human input. Tell the user what appeared and ask them to handle it; do not guess or take over unrelated UI. Call `close_binary` when the investigation is complete. ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [morluto](https://github.com/morluto) - **Source:** [morluto/rea](https://github.com/morluto/rea) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-morluto-rea-rea-analysis - Seller: https://agentstack.voostack.com/s/morluto - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.