7aa1b51282
* feat(diagnostics): report a byte entropy profile for one local file The diff adds the MCP tool inspect_byte_entropy and the CLI command inspect-byte-entropy, both implemented by ByteEntropyService. One absolute regular file is read offline into observed Evidence: file-wide SHA-256 and Shannon entropy, then fixed blocks and adjacent runs for an optional window, using a power-of-two block size from 256 to 65536 (default 4096), with high at 7.2 or above and low at 1.0 or below. A window past EOF, a missing path, or a non-file is an input error; a size or identity change during the read is an artifact-changed error; empty input reports entropy 0; cancellation is honored before and during the read. Summary detail retains the complete series and returns file entropy, counts, and the ten longest runs for inspect_analysis_view, while the registered effect remains read-only Evidence and the diagnostics docs record the operation and its errors. * fix(diagnostics): flag zero-size files as not shown empty Generated files such as Linux /proc entries report size 0 while holding content, so inspect_byte_entropy read nothing and returned an empty-looking report. A file that reports size 0 now carries a limitation that the result does not show the file is empty. The result stays a success because the tool reads the declared size, which the file-stability checks depend on. * fix(mcp): reject unsupported diagnostic summaries before inspection * fix(ci): repair integrated checks and Hopper test baseline * test(entropy): use shared MCP schema verification after merge * fix(catalog): list inspect_byte_entropy under its own provider Adding inspect_byte_entropy to BINARY_DIAGNOSTICS_TOOL_CONTRACTS put it under pwntools-elf in the generated product catalog, because the pwntools group took every binary diagnostics tool except inspect_pe_resources. The service reports provider byte-entropy. Add a BYTE_ENTROPY_PROVIDER identity beside PE_RESOURCES_PROVIDER, use it in ByteEntropyService, give it its own catalog group, and name the pwntools tools (inspect_binary_layout, inspect_recorded_crash) explicitly so a new diagnostics tool is not attributed to pwntools by default. The catalog test pins both groups. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01KFTE4BHbGYzgf8Uhzcppdh * fix(cli): resolve the byte-entropy path with absoluteCallerPath main replaced the node:path resolve import in binaryDiagnosticsCommands.ts with absoluteCallerPath (#4067), so the byte-entropy command's resolve(args.path) no longer type-checks once the PR is merged with main. Use absoluteCallerPath like the other commands, and add src/filesystem/callerPath.ts matching main so the branch builds on its own. * fix(diagnostics): retain entropy read cleanup ownership * docs(diagnostics): explain entropy output capacity * fix(diagnostics): preserve entropy cancellation outcomes * fix(diagnostics): close the entropy input and warn on large reports Public inspect_byte_entropy input now uses publicInputStrictObject before detail is added, so unknown keys stay rejected on the advertised schema. The tool description warns that complete output can become very large and points callers to a shorter length or a larger block_size. Co-authored-by: morluto <morluto@users.noreply.github.com> * fix(diagnostics): keep byte-entropy registration mergeable with main Register inspect_byte_entropy beside layout inspection and reject unretained summaries before the file read, without editing workflows. Co-authored-by: morluto <morluto@users.noreply.github.com> * fix(diagnostics): register byte entropy with the shared tool options Use toolRegistrationOptions so the handler typechecks on this branch and on main, and still refuse unretained summaries before the file read. Co-authored-by: morluto <morluto@users.noreply.github.com> --------- Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com> Co-authored-by: morluto <76467478+morluto@users.noreply.github.com> Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com> Co-authored-by: Kaoru0822 <208281322+kaoru0822-kitauji@users.noreply.github.com> Co-authored-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: morluto <morluto@users.noreply.github.com>
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REA: Reverse Engineer Anything
One MCP for reverse engineering across binaries, applications, and runtime behavior.
See a feature you like. Understand how it works, down to the binary level.
Quick start · How REA works · What you can analyze · Showcases · FAQ · Documentation
npx rea-agents setup
Important
Get REA from morluto/rea, rea.tools, or the rea-agents npm package. Follow the installation and release links from these official sources. A similar repository name or copied README does not establish that a download is official.
See a feature in an app that you want in your own product? Ask your agent to investigate it with REA. It can inspect the app without its source code, explain how the feature works, show the evidence, and build a version for your project.
REA connects your agent to tools for inspecting native binaries, JavaScript and Electron apps, .NET assemblies, and websites. You can also use the same tools from your terminal. Analysis runs locally, and results include the evidence and limitations behind each conclusion.
Setup registers REA with your agent and installs matching workflow instructions. Native analysis can use an existing Hopper, Ghidra, or IDA installation; setup can optionally install Hopper with approval. Static JavaScript analysis needs no native analysis engine.
Visit the REA website for setup instructions, illustrated guides, and real case studies.
Quick start
On Linux, Ghidra, JADX, firmware tool launches and static JavaScript/Electron
analysis require a procps-compatible ps on REA's PATH for process ownership
checks. Recovery steps are in docs/installation.md under
"Linux owned-process prerequisite".
Set up your agent
With Node.js and npm installed, run:
npx rea-agents setup
Choose your agents, review the proposed changes, and approve them. Setup adds REA's MCP server and matching workflow instructions, with backups of existing configuration. Restart your agent afterward.
Setup supports Claude Code, Codex, Cursor, Gemini CLI, Grok Build and other agents. See installation and setup for provider configuration and manual MCP registration.
MCP uses compact input schemas by default to reduce context overhead. Set
REA_MCP_INPUT_SCHEMA_PROFILE=full in your MCP registration when you need the
complete advertised field guidance and nested validation details. Both profiles
keep the full tool set and canonical server validation. See
"Compact input schema profile" in the MCP contracts guide.
Ask your agent
Understand how search works in the Notes app, show me the evidence, and build a
similar feature for my project.
Replace Notes with your target app and the feature you want to understand.
Use the terminal
Inspect an extracted JavaScript/Electron app directory or ASAR:
npx -y rea-agents@latest analyze-javascript-application /absolute/path/to/app --json
The result includes modules, imports, Electron boundaries and their evidence.
Replace the path with your target, such as "D:/apps/example" on Windows.
To install the rea command for regular use:
npm install --global rea-agents
rea --help
For native analysis, configure a provider first. See the CLI and Evidence guide for native commands, provider selection, snapshots and scripting.
Update REA
REA changes quickly, and new releases include frequent bug fixes. Keep your installation up to date.
For a CLI installed with npm install --global or bun add --global:
rea update
rea --update is an alias for this verified workflow and accepts the same global
output flags. Use rea update when combining it with other command controls.
Updater commands retain at most 4 MiB of stdout and stderr combined. Oversized metadata replies are rejected after the command exits; verbose installs continue with bounded diagnostics. Human progress output respects terminal backpressure and waits for submitted writes to finish.
Bun global updates require Bun 1.2.17 or later. With an older Bun release,
upgrade Bun manually before running rea update.
To refresh your agent registrations and skill, run the setup command printed by the update.
If you use npx, update your agent setup with:
npx rea-agents@latest setup
Review the setup changes and restart your agent. For one-off CLI commands,
use npx rea-agents@latest followed by the command. With Bun, use
bunx rea-agents@latest in place of npx rea-agents@latest.
How REA works
Your agent calls REA through MCP to inspect the target and trace relevant code. REA returns findings with their evidence. The agent uses them to ask follow-up questions, explain the behavior, or write and test an implementation. CLI commands use the same workflows.
What you can analyze
REA requires Node.js 22.x (>=22.19), 24.x (>=24.11), or 26+, plus npm. Additional tools and host support depend on the target:
| Target | What REA returns | Requirements and guide |
|---|---|---|
| Desktop installations | Runtime candidates, supporting files, component markers and next probes | Built-in bounded directory/header inspection; desktop applications |
| Native binaries | Pseudocode, assembly, strings, symbols, calls and references | Hopper, Ghidra or IDA; native analysis |
| Offline ELF layout | Sections, segments, original symbols/relocations and static mitigation candidates | Caller-supplied pwntools on Linux x64; binary diagnostics |
| Go binaries | Embedded compiler version, modules, replacements and build settings | Built-in static ELF/PE/thin Mach-O inspection; no Go installation required |
| GPU code objects | CUDA/HIP targets, selected kernel parameters and resources, retained PTX text | Built-in static ELF/PE/fatbin/CUBIN/PTX inspection; GPU code objects |
| Model artifacts | GGUF / safetensors metadata, tensor declarations and derived totals | Built-in header inspection; optional full-file hash; model files |
| IL2CPP metadata | Unity global-metadata.dat assembly images, type and method names and index ranges | Built-in static decoding of versions 24, 27, 29, 31 and 39; no Unity required |
| Godot PCK | Archive inventory and extraction, original header/directory facts and selected content identities | Built-in static formats 2, 3 and 4; no Godot required |
| Rust binaries | Embedded cargo-auditable crate names, versions, sources and dependency edges | Built-in static ELF/PE/thin Mach-O inspection; Rust binaries |
| WASM artifact | Validation, sections, exact import/export WAT forms and decoded WAT | Caller-supplied WABT 1.0.42; inspect_wasm_artifact |
| EVM bytecode | Dispatch selectors, byte offsets, inferred arguments and mutability | Local raw/hex carrier on Linux x64; offline EVM guide |
| SQLite databases | Tables, columns, indexes, views, triggers and selected ordinary-table rows | Local database/WAL snapshot; Node.js 24.x >=24.15 or 26+ with native SQLite limits |
| Recorded Linux crashes | Raw notes, every recorded thread's registers/signals and optional mapping candidates | Caller-supplied pwntools on Linux x64; optional GDB/pwndbg; recorded crashes |
| JavaScript / Electron | Modules, imports, source maps, routes, IPC and native add-on relationships | Node.js and npm; Linux: procps-compatible ps; application analysis |
| Websites | Page structure, scripts, network observations and requested screenshots | A Chrome-family browser; browser analysis |
| Saved network captures | Requests, responses, exposed payloads and source locations | HAR or Fiddler Everywhere SAZ; mitmdump on Linux for native mitmproxy; capture guide |
| .NET assemblies | Metadata, CIL instructions, declared native dependencies and build comparisons | None (static only); managed-code guide |
| Android APKs | Manifest declarations, classes, decompiled methods and references | Headless JADX and a full JDK on Linux/macOS/Windows x64; Android guide |
| Android devices | Devices, packages, processes, logs, dumps, screen captures, and APK/file transfers | Caller-supplied adb (emulator or hardware); ADB guide |
| JEB projects | Engine-backed project units, artifact digests and type/method pseudo-code | A caller-started JEB client serving MCP, selected with REA_JEB_MCP_URL; JEB guide |
| Android resources | Decoded manifest, string tables, locales and version facts | Caller-supplied Apktool launcher; resource guide |
| Flutter apps | Dart snapshot hash, per-ABI library digests and engine build provenance | None (static APK parsing); Flutter guide |
| Firmware | Regions, extraction results and native-analysis handoffs | Binwalk / Unblob on Linux; firmware guide |
| Recorded packets | Selected fields, repeated values, filters and decode-as rules | Linux: TShark 4.x + prlimit; capture guide |
| Packet summaries | Endpoints, DNS, TLS SNI, protocol distribution and HTTP requests | Caller-supplied tshark and capinfos (Linux-verified); pcap guide |
| Recorded logic signals | Decoder annotations, sample ranges and diagnostics | Linux: sigrok-cli 0.7.2 + prlimit; signal recordings |
| Packages and resources | File inventories, digests, plists, Apple bundle anatomy and extracted resources | Artifact and JavaScript guide, Apple applications |
| Process behavior | Terminal output, interactions, exit and filesystem observations, and run comparisons | Linux/macOS with a native PTY; process capture |
| PyInstaller executables | CArchive members, Python version, entry scripts and extracted bytecode | None (static only); Python packaged applications |
Static JavaScript and .NET inspection read the supplied files without running the application. Runtime capture runs or interacts with the selected target using your user permissions; each runtime guide describes its effects.
For offline native-binary inspection, REA also supports caller-supplied GNU objdump and Rizin. See the reverse-engineering tools guide for provider setup, CLI commands, and Evidence limitations. REA does not install or update either provider.
Native formats and host support vary by provider. See
Hopper and Ghidra setup, the
IDA guide (including an optional native MCP bridge), the
Kuna decompiler guide, and
experimental Windows Ghidra support.
Ghidra also supports 16-bit DOS analysis.
For large binaries, raise the provider's startup deadline with
REA_GHIDRA_STARTUP_TIMEOUT_MS or REA_HOPPER_STARTUP_TIMEOUT_MS.
For provider selection, see the CLI guide.
Check release availability
for features added since the latest npm release.
Showcases
DX-Ball: reconstruct a sound-pan calculation
Follow a sound call into its position-to-pan helper, inspect the instructions, and turn incomplete pseudocode into C. The reconstruction passes 3,205 original-x86 cases and reproduces all 63 compiled function bytes.
Read the case study · Reconstruction repository
Notion: trace the Electron clipboard bridge
Find the renderer's clipboard API, follow it through preload and IPC into the main process, and inspect the rich clipboard format.
TH04: recover a DOS bullet-ring calculation
Inspect the original PC-98 game's 16-bit instructions, recover the fixed and aimed angle calculations, and compare the reconstructed C++ with the historical compiler output.
Read the case study · Reconstruction repository
If you've used REA on something interesting, we'd love to see it. Share your case in an issue or a pull request, including the target, your question, how REA helped, and what you found.
FAQ
Which agents can use REA?
Any agent that supports local MCP servers. Setup configures the supported agents; other clients can use manual MCP registration.
Do I need Hopper, Ghidra or IDA?
Deep native analysis uses one of them. Static JavaScript and .NET inspection work without a native analysis engine. Setup can install Hopper after approval; Ghidra and IDA use your existing installations. See provider setup.
Do I need to start Hopper first?
REA starts Hopper when an operation needs it. On macOS, a first-run dialog may ask you to choose demo mode or activate your license. Complete that prompt in the same user session before your first CLI/MCP operation or unattended job. Open Hopper manually if needed. See Hopper startup and troubleshooting.
What does installing the skill from skills.sh do?
The skill supplies investigation instructions for your agent. Use npx rea-agents setup
to register REA's MCP server and install the matching instructions, then restart
your agent. See skill-only installation.
What code does REA return?
Native analysis returns pseudocode and assembly. JavaScript/Electron analysis recovers modules and their relationships. Your agent uses these findings to write and test an implementation; the showcases give worked examples.
Does REA upload my app?
REA analyzes targets locally. Your agent receives the tool results, and its model provider has its own data policy.
What should I do if I hit a bug?
Update first; a recent release may already fix it.
For a CLI installed with npm install --global or bun add --global:
rea update
For agent setup through npx:
npx rea-agents@latest setup
If you're using an agent, complete the setup refresh and restart it. Retry the same task. If the problem persists, open an issue with your REA version, target type, steps to reproduce and error output.
Documentation
Start with the website's worked guides. For exact options, prerequisites and result contracts:
- Installation and setup: agent registration, provider configuration, updates and uninstall.
- Readiness and troubleshooting: diagnose one agent or analysis engine.
- CLI and Evidence: commands, provider selection, snapshots, import/export and exit statuses.
- MCP contracts and agent prompts: tool results, sessions and guided investigations.
- Tool catalog: generated inventory of tools, providers and CLI commands.
- Roadmap: planned work and capability trackers.
Report vulnerabilities through SECURITY.md.
Star history
🎉 300,000 GitHub stars — thank you!
Thanks to everyone using REA, reporting bugs, requesting features, testing builds, and contributing fixes.
Disclaimer
See DISCLAIMER.md for responsible-use guidance.
The project's position on illegal or unauthorized use covers all REA versions, distribution channels, and platforms; each copy retains its applicable licenses.
REA is for lawful research, education, interoperability, software preservation, and analysis of software you own or are authorized to examine.
Contributing
We'd love your help with REA! Open an issue to report a bug or suggest a feature, or send a pull request to improve the code or docs.
See CONTRIBUTING.md for development setup and checks, testing for verification lanes, and the architecture map for the project structure.
License
REA-authored code is licensed under MIT. Third-party material retains its own licenses and copyright notices; see Third-party notices for the dependency inventory, preserved license texts, and external-tool terms.
You must legally obtain and be authorized to use commercial tools, including IDA Pro / Hex-Rays decompilers, Hopper, and JEB, under their applicable licenses. REA grants no tool license, key, or activation entitlement. Trials and demos remain subject to vendor terms, including user, feature, automation, and output sharing restrictions. Cracked copies, stolen keys, unauthorized key sharing, and bypassing license restrictions are not authorized. This guidance does not amend MIT or third-party licenses.