Files
rea/README.md
T
e4d3e1399d feat(flutter): identify Dart snapshot builds and inspect AOT payloads by pure APK parsing (#1582)
* feat(flutter): identify Dart snapshot builds by pure APK parsing

Add a flutter-provider family with one operation, identify_flutter_build,
that reads an APK's lib/<abi>/libapp.so and libflutter.so through the
hardened ZIP reader and reports build facts as observations:

- The Dart VM snapshot hash, read 20 bytes after every snapshot magic
  (f5f5dcdc). The vm and isolate sections are cross-checked: agreeing
  sections collapse to one snapshot_hash, disagreeing sections keep every
  candidate with snapshot_hash null and partial coverage.
- Per-ABI library digests and byte sizes, plus the engine library's GNU
  build-id note and any labeled 'Dart VM version' or Android clang/LLVM
  toolchain strings, verbatim; release builds without a version string
  report null rather than a guess.
- The APK is digested before parsing so Evidence binds the observation to
  the exact input, and a target with no libapp.so reports not-detected
  with complete coverage.

The scanner is streaming with explicit pending-magic and rescan
bookkeeping, so chunk boundaries cannot double-count or drop sections, and
magic-free streams never accumulate. No engine, no external lookups: the
hash-to-SDK mapping stays with external datasets by design.

Verified against Flutter Gallery 2.9.2 (112 MB, three ABIs): every ABI
reports the same agreeing hash 65817c30a78bb44c3dc3771876b6010a from two
sections, per-ABI build-ids, and the clang toolchain line; a plain
aapt2-built APK reports not-detected with complete coverage. Scanner
goldens come from the same libraries. READMEs carry the new 'Flutter apps'
row in every supported language.

* feat(flutter): inspect Dart AOT snapshots through the ELF symbol table

Add inspect_dart_aot to the flutter family: for one ABI's libapp.so it
locates the four _kDart*Snapshot* symbols through the ELF dynamic symbol
table (ELF32 and ELF64 little-endian, bounds-checked reads; a payload
without exported symbols is refused), reports each section's offset and
size, validates data-section headers (magic, kind, length; instructions
sections honestly report nulls for the fields their layout does not
carry), and projects a bounded string pool from the isolate data section:
distinct package: source URIs (the app's dependency inventory), dart: SDK
URIs, and identifier-shaped tokens, each with counts, bounds, and partial
coverage when truncated.

The string pool is labeled as a byte-pattern projection, not deserialized
cluster semantics: typed class and function recovery remains an
SDK-specific parser, which the snapshot hash now unlocks. The ABI is
caller-selected with a deterministic default (arm64-v8a, x86_64, then
first available).

Verified against Flutter Gallery 2.9.2: all four symbols on both ELF64
(arm64-v8a) and ELF32 (armeabi-v7a) images, header validation, hash
agreement with identify_flutter_build, and a 756 package: / 201 dart:
URI pool from the isolate data section; goldens in DartElf.test.ts come
from the same libraries.

* fix(flutter): own snapshots, bound image reads, and preserve cancellation

Mirror the ownership bar the maintainers applied across the merged JEB,
ADB, and Apktool PRs:

- Copy the admitted APK into a provider-owned, read-only snapshot (EXCL
  create, chmod 0400) before digesting and parsing; every later read uses
  the snapshot, so a concurrently modified original cannot mix into one
  observation. The result reports the snapshot's byte size and digest.
- Retain failed snapshot-root cleanup in a provider set and retry it on
  close(), throwing an aggregate error when a root is still owned; root
  removal is injectable so the retention is testable.
- Allocate the AOT image buffer at exactly the declared library size
  before reading (bounded before allocation, not concat-after-stream),
  keep the 256 MiB ceiling, and check cancellation between digest and
  stream chunks through a captured abort reason.
- Accept APK paths containing spaces (covered by a fixture test) and
  escape the ABI pattern's dash for v-mode regex compatibility.

Also add tests for cleanup retention with close retry and for
cancellation before any snapshot root is created.

* docs(flutter): cover the Italian README with the Flutter row

The Italian translation landed between the merged feature PRs; its table
now carries every merged row plus this one, keeping its documentation-link
set identical to README.md.

* fix(flutter): make the ABI pattern portable for v-mode validators

Use a hex-escaped hyphen in the ABI character class, matching the form
the ADB portability fix uses, so clients compiling advertised schemas in
unicodeSets mode accept the inspect_dart_aot input schema.

* refactor(flutter): reuse shared harnesses and deduplicate the vertical

The duplicate-detection gate (jscpd, 2.5% threshold) tipped to 2.51% with
the flutter files added. Reuse the existing machinery instead of repeating
it:

- FlutterBuildAnalysisService delegates to executeProviderOperation, the
  shared admission/Evidence composition, instead of restating its body.
- The CLI registers both commands from one table-driven spec.
- Boundary tests use the shared serveCli and assertAdvertisedMcpContracts
  harnesses rather than hand-rolled equivalents.
- The provider test consolidates the four payload-shape cases into one
  table-driven case; the service test uses one admission table and
  distinct phrasings.

Duplicate lines fall from 2.51% to 2.48%, back under the gate.

* fix(flutter): address review findings from real-app verification

CassieFox23 verified the PR against three real F-Droid Flutter apps and
a control app, and found five gaps. All are fixed and re-verified against
cone (info.tangential.cone), one of the tested apps:

- Build-id: the scanner now reads the descriptor length from the note
  header instead of assuming 20 bytes, so 8-byte ids from older
  toolchains parse; the schema accepts 8-128 hex characters. Verified
  against cone's readelf-reported ids on all three ABIs.
- Compiler line: the toolchain capture bound rises from 200 to 500
  characters, keeping cone's 262-character clang line verbatim.
- Zero-byte libapp.so: the extraction target is created before streaming,
  so an empty entry yields a clean unsupported_target refusal for
  inspect_dart_aot and elf_header_valid: false with partial coverage for
  identify_flutter_build, instead of a raw ENOENT with code UNKNOWN.
- Truncated library: identify_flutter_build marks fewer than two snapshot
  sections as partial coverage with a limitation naming the count, and a
  missing ELF magic gets its own limitation.
- Docs: the default ABI preference now matches the code exactly
  (arm64-v8a, x86_64, x86, armeabi-v7a, then the rest alphabetically).

Also: every test that read the author's /tmp/opencode goldens now builds
a self-contained synthetic ELF64 image with dynsym, four snapshot
symbols, two snapshot sections, and a string pool, so the suite runs
anywhere; the verify lane now requires a present hex build-id per ABI
instead of accepting null.

* fix(flutter): address the Codex review findings

Eight findings, all applied:

- P1: SnapshotHashScanner keeps candidates in a Set (no quadratic
  Array.includes) with a 64-distinct-hash cap, so a hostile payload of
  magic+hash records cannot stall the scan or bloat the response.
- P1: projectStringPool stops admitting new distinct entries once each
  category reaches twice its projection bound and reports
  collectionCapped; allocation and sorting now track the response, not
  the payload.
- P2: ZIP reader rejections during entry iteration or entry streaming
  map into the typed error algebra (cancellation vs input refusal)
  instead of escaping as unhandled exceptions in both operations.
- P2: magic_valid now marks coverage only for the *Data symbols; a
  complete four-symbol image with valid data magics reports complete
  coverage (the instruction symbols intentionally lack the magic).
- P2: the MCP server closes the Flutter provider during shutdown, so a
  retained snapshot root is retried and reported, not leaked.
- P2: LabeledStringScanner commits matches only when a printable run is
  delimiter-terminated; the carry grows to 600 bytes so a 500-character
  toolchain line survives any chunk boundary untruncated.
- P2: both Flutter tool effects declare writesFilesystem: true; the
  owned APK snapshot and extracted libapp.so are temporary writes.
- P2: the verify lane asserts every ABI agrees on exactly one snapshot
  hash instead of discarding the computed set.

* fix(flutter): address the second Codex review round

Nine findings on the first-round fixes:

- P1: identify_flutter_build enforces a cumulative extraction budget
  (768 MiB) across every library entry, not just per library, so an APK
  with many ABIs cannot stream an unbounded total.
- P1: a single NUL-free printable run stops materializing at 1024 bytes
  and marks the pool capped, so an adversarial one-run section cannot
  allocate unbounded strings.
- P1: ELF cString bounds the NUL-terminator scan to the name maximum
  plus one, so malformed symbol tables cannot scan the whole image per
  entry.
- P2: mapReaderFailure distinguishes ArtifactReaderFailure texts —
  budget/limit rejections map to resource constraints, integrity
  failures (CRC/overlap/signature) to their own input refusal — instead
  of collapsing all reader failures into one message.
- P2: the labeled-string carry is cleared when a delimiter commits a
  run, so consecutive toolchain lines are never concatenated.
- P2: string-pool counts are renamed *_count_at_least and documented as
  lower bounds, because capped collection discards values beyond twice
  the projection bound.
- P2: inspect_dart_aot marks hash disagreements, non-pair source counts,
  and candidate-cap saturation as partial coverage.
- P2: only valid lowercase-hex hash records count as snapshot sources;
  complete magic records with non-hex fields do not inflate agreement.
- P2: the per-entry size refusal in inspect_dart_aot moves after ABI
  selection, so an oversized unselected ABI no longer refuses a small
  request.

* fix(flutter): address the third Codex review round

Five findings:

- P2: the owned snapshot revalidates the source after the copy (size,
  mtime, inode), so an in-place replacement or swap mid-copy refuses
  the observation instead of publishing mixed bytes.
- P2: a failed ZipArtifactReader close retains the snapshot root for
  close() retry instead of silently swallowing the descriptor leak,
  in both operations.
- P2: snapshot headers are parsed within their symbol bounds and a
  symbol smaller than the 16-byte header reports magic_valid false,
  so trailing-image bytes can no longer fake a valid data section.
- P2: the verify lane counts provider.close() cleanup failures as
  lane failures instead of certifying a run with retained roots.
- P2: LabeledStringScanner reports toolchain_capped when further
  distinct matching lines are observed past the 4-line projection;
  identify marks such results partial with a naming limitation.

* fix(flutter): address rounds three and four of the Codex review

Round three (one missed finding) plus round four (five findings):

- P2: the GNU build-id note descriptor size is decoded from all four
  bytes of the little-endian field, rejecting nonzero high bytes
  instead of masking them to 16 bits.
- P1: the Flutter MCP handlers route through createContractToolHandler
  and the session's analysisAdmission, so close_binary and snapshot
  operations drain in-flight Flutter calls instead of racing them.
- P2: the owned-snapshot copy is a streamed, abort-checked write (no
  copyFile), so cancellation stops the write promptly while the
  source-identity revalidation (size, mtime, inode) still guards
  against mid-copy replacement.
- P2: identify marks any snapshot_hash_sources value other than exactly
  two as partial, matching the inspection path's pair requirement.
- P2: the verify lane refuses to run without --apk (exit 2) instead of
  printing a false-green pass, and the engine check requires every
  libapp-carrying ABI to have a present libflutter with a valid hex
  build-id rather than filtering missing engines away vacuously.

* fix(flutter): address the fifth Codex review round

Six findings plus the upstream duplication baseline:

- P2: the flutter-provider kind reports available in the capability
  inventory, so binary_session no longer lists always-registered
  Flutter tools as provider_missing.
- P2: printable runs that exceed the 1024-byte cap are discarded at
  their delimiter instead of emitting their truncated prefix as a
  fabricated observation.
- P2: ELF symbols must fit inside the file-backed portion of their
  PT_LOAD segment (p_filesz), so addresses in gaps or BSS are refused
  instead of accepting unrelated bytes.
- P2: the build-id carry spans the complete 80-byte maximum note
  (16-byte header + 64-byte descriptor) so chunk-boundary splits
  cannot drop the first byte.
- P2: the labeled-string carry is sized for the toolchain pattern's
  true 605-byte maximum, not the previous 600.
- P2: the AOT completeness predicate requires exactly two sources and
  one candidate unconditionally, so zero-source images with valid data
  magics report partial instead of complete.

Also: the shared ELF fixture builder and snapshot-section helper moved
to a dedicated FlutterTestFixtures module, eliminating cross-file test
duplication; jscpd now passes at 2.50% while main sits at 2.52%.

* fix(flutter): address the sixth Codex review round

Five findings:

- P2: snapshot-hash scanning is bounded to the exported data symbols'
  byte ranges, so decoy or stale magic/hash sequences elsewhere in the
  image cannot inflate source counts or contribute candidates.
- P2: labeled-string runs longer than the carry bound are rejected
  instead of truncated, preventing a regex prefix from being published
  as a verbatim source string.
- P2: the AOT image reread checks cancellation between file reads and
  before the synchronous parsing stage, so a cancelled caller cannot
  receive a success from a completed 256 MiB read.
- P2: the verify lane requires exactly two snapshot sources per ABI,
  matching the provider's pair requirement, instead of accepting any
  count >= 2.
- P2: ELF section and program header entry sizes are validated against
  the class-defined minimum widths before walking either table, so
  undersized entries cannot cause field reads to cross into
  neighboring bytes.

* fix(flutter): address the seventh Codex review round

Six findings:

- P2: data-symbol ranges are deduplicated by offset and size, so aliased
  symbols mapping to the same bytes are scanned once and the result
  marks partial coverage with a limitation naming the shared range.
- P2: openEntrySafely forwards return/throw to the underlying Readable's
  iterator, so an early for-await exit closes the ZIP entry stream and
  releases its producer instead of leaking a backpressured pipe.
- P2: inspect_dart_aot now reports snapshot_hash_candidates and
  snapshot_hash_sources alongside snapshot_hash, so a null hash from
  conflicting evidence is distinguishable from missing hash data.
- P2: overlong printable runs only set toolchain_capped when they begin
  with a recognized label prefix (Dart VM version: or Android (); other
  long strings such as license text are skipped without marking partial.
- P2: readElfSymbol falls back to PT_DYNAMIC/DT_SYMTAB when section
  headers are absent (e_shnum 0, ET_DYN), so stripped Flutter libraries
  with exported snapshot symbols are no longer refused; the dynamic
  table is bounded by DT_STRSZ, DT_SYMENT, and the image end.
- P2: the verify lane exercises inspect_dart_aot for every ABI carrying
  libapp.so, not just the preferred default.

* fix(flutter): address the eighth Codex review round

Five findings:

- P2: each data-symbol range gets a fresh SnapshotHashScanner so the
  carry from one noncontiguous slice cannot fabricate a record spanning
  into the next; results are aggregated after scanning.
- P2: dynsym name lookups are bounded to the linked string table —
  st_name offsets outside the table and terminators beyond it are
  rejected instead of reading unrelated payload bytes as symbol names,
  in both the section-header and PT_DYNAMIC paths.
- P2: identify_flutter_build routes its reader.entries and reader.open
  calls through the same collectEntriesSafely and openEntrySafely
  wrappers as inspect_dart_aot, so malformed ZIPs surface as input
  refusals instead of AnalysisProtocolError.
- P2: mapReaderFailure recognizes ArtifactReaderFailure texts carrying
  a cancelled reason, mapping them to AnalysisCancelledError instead
  of AnalysisInputError.
- P2: the cumulative extraction cap is enforced inside the chunk loop,
  not after each library completes, so refusal happens before the
  remaining bytes are streamed and hashed.

* fix(flutter): harden streaming, sizes, and cancellation after self-review

Four issues found in a systematic self-audit across all bug classes
from eight Codex rounds:

- createReadStream in both the digest function and the owned-snapshot
  copy now receives the AbortSignal directly, so cancellation aborts
  the filesystem read at the source instead of waiting for the next
  chunk to arrive on a slow filesystem.
- The owned snapshot enforces a 2 GiB APK-level size cap before any
  copy I/O, so a path pointing at an enormous file is refused before
  disk usage grows.
- identify_flutter_build preflights the sum of declared entry sizes
  against the 768 MiB cumulative budget, refusing before any ZIP
  extraction when the declared total already exceeds it.
- The LabeledStringScanner triple result() call is collapsed to a
  single invocation (the previous code called result() three times in
  the emission, relying on end() being idempotent).

No behavior change for valid inputs; all 36 tests, check:fast, and
the cone verify lane pass unchanged.

* fix(flutter): require structurally parseable ELF headers for complete coverage

CassieFox23's third corrupt-header case: an ELF with valid magic but
zeroed section/program header offsets passes the 4-byte magic check
and the byte scanner still finds hash patterns in the data sections,
so identify_flutter_build reports complete coverage for a structurally
broken file.

The elf_header_valid check now also verifies beyond the magic:
e_type must be a known value (ET_REL/ET_EXEC/ET_DYN), at least one
of e_shoff/e_phoff must be non-zero, and at least one of
e_shnum/e_phnum must be non-zero. A file with valid magic but zeroed
structure reports partial coverage with the existing ELF-magic
limitation.

* fix(flutter): validate ELF and snapshot coverage

Share bounded ELF header parsing between identification and inspection. Accumulate headers across ZIP chunks and validate table entry widths and extents before claiming complete identification coverage.

Bind AOT hashes to the exported VM and isolate headers, validate stored snapshot lengths including the magic bytes, and preserve partial evidence for missing, malformed, aliased, or overlapping data headers.

Preserve native stream cancellations and APK resource constraints across both operations. Bound snapshot copies while streaming and retain useful input-failure diagnostics and lower-bound count wording.

Validation: 72 focused tests; check:fast; check including formatting; docs:check; test discovery; jscpd; real cone APK and non-Flutter control on Linux. Verified CLI/MCP parity for valid and corrupted ELF headers and AOT inspection across three ABIs. Native Windows and macOS were not run.

* fix(flutter): unify artifact ownership and bound ELF evidence

* fix(flutter): preserve ELF provenance and partial coverage

Read GNU build IDs only from bounded ELF note ranges and retain conflicting candidates. Preserve source versus owned storage failures and honor cancellation through parsing and final cleanup.

Separate snapshot structure from string-pool coverage. Verify every Gallery ABI with digest-bound engine labels and URI counts, and document the supported snapshot-kind layout.

---------

Co-authored-by: REA Contributor <contributor@rea.tools>
Co-authored-by: morluto <76467478+morluto@users.noreply.github.com>
2026-10-12 22:35:55 +08:00

19 KiB

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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.

npm version MCP tool catalog Node.js requirements skills.sh MIT license Discord

morluto%2Frea | Trendshift

Website · Guides · Showcases

Quick start · How REA works · What you can analyze · Showcases · FAQ · Documentation

npx rea-agents setup


REA launching its analysis bridge inside Hopper while inspecting a native binary



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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

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.

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

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.

REA investigation flow: your agent asks about a local target, REA inspects and traces it using analysis tools, and the agent uses the returned code, references and unknowns to explain, implement and test.

Open the full-size figure.

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
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
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
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; 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; mitmdump on Linux for native mitmproxy captures; 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
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

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.

Native formats and host support vary by provider. See Hopper and Ghidra setup, the IDA 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

Illustrations of the DX-Ball sound-pan, Notion clipboard-bridge, and TH04 bullet-ring 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.

Read the case study

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:

Report vulnerabilities through SECURITY.md.

Star history

🎉 110,000 GitHub stars — thank you!

Thanks to everyone using REA, reporting bugs, requesting features, testing builds, and contributing fixes.

REA GitHub star history

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

MIT

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.