reverify

Reverify

Stop your AI from making things up. It proposes; deterministic tools check every claim against ground truth, and only what's verified counts.

AI is confident and often wrong: it invents an API, a struct field, an offset, or what a function does, and says it like fact. Reverify makes a deterministic tool the judge — the model proposes a claim, the tool checks it against the actual artifact, and it comes back VERIFIED / REFUTED with evidence. The model never gets to assert a fact on its own.

Two things it does today:

• Keeps your AI honest — every structural or behavioral claim is checked against ground truth, not trusted, and only what survives becomes a fact (reverify verify, or the MCP server your agent already talks to).
• Keeps your AI's context from rotting — instead of a lossy auto-summary, reverify rollover hands the session off to a file and starts a fresh one, so long tasks don't drift or need /clear. Works in Claude Code, Codex, Gemini CLI and OpenCode.

The hardest place to prove the first point is binary reverse engineering, where hallucination is worst — so that's where the numbers come from. On 71 real Windows system files the AI's textbook answer was wrong 97% of the time; reverify caught every one and never accepted a wrong claim (0 of 71; the same gate runs in CI on Linux and macOS every push, and an independent aarch64 run found the same) (EXAMPLE.md, BENCHMARK.md; python benchmarks/prologue_prior.py).

The problem

Language models are great at reading code and unreliable at reverse engineering. Ask a model to reconstruct a struct or an algorithm from a binary and it will confidently invent offsets, sizes, and behavior. In binary analysis this hallucination problem is far worse than in source code, and "did the model just make that up?" is the single biggest blocker to using AI for real RE.

What Reverify does

Reverify pairs a language model with a deterministic, pure-Python RE toolkit and makes the toolkit the judge. The model proposes; the tools verify. A hypothesis about a structure or an algorithm is only reported once it has been checked against the actual bytes — disassembled, pattern-matched, or executed in the emulator — so the output is grounded in the binary instead of the model's imagination.

• Deterministic core — PE/ELF/Mach-O parsing, x86/x64/ARM/ARM64 disassembly, AOB pattern scanning, CPU emulation, Protobuf/TLV dissection, Frida hook generation. Pure Python out of the box; installs clean with no Ghidra.
• Mature engines, optional — with pip install "reverify[full]" the toolkit upgrades itself in place to capstone (disassembly), unicorn (real CPU emulation), lief (PE/ELF/Mach-O) and Z3 (proofs); pip install "reverify[angr]" adds angr for function boundaries, the call graph and cross-references. Not installed? It falls back to the pure-Python core. reverify backends shows what's active.
• Grounded, not guessed — structural claims are verified against the binary by the tools.
• Not only binaries — reverify equiv <reference> <candidate> --lang python (or C) runs a candidate implementation and a reference over shared inputs and checks they agree, so an AI's rewrite or refactor is tested, not trusted — a refutation comes back with the input and both outputs. The same rigour, aimed at ordinary source code.
• Agent-native — ships as an MCP server, so Claude Code, Cursor, and other agents can call the tools directly; also a plain CLI.

Reverify is for authorized reverse engineering — malware analysis, CTF, interoperability research, and software you own or are permitted to analyze. See SECURITY.md.

Quick start

# Install the CLI + MCP server from PyPI:
pip install reverify        # pure-Python core; or "reverify[full]" for capstone+unicorn+lief
reverify auto sample.bin --json

# Or run straight from a checkout — pure standard library, nothing to install:
python reverify/cli.py auto sample.bin --json
python reverify/cli.py parse-pe sample.exe --json
python reverify/cli.py disasm 90505831C0C3 --arch x86_64

The verification loop

This is what the name is about. A claim is any hypothesis about the binary; the deterministic tools are the judge and hand back VERIFIED, REFUTED, or INCONCLUSIVE together with the bytes they actually observed:

reverify verify sample.bin --claim '{
  "kind": "instructions", "offset": 4096,
  "mnemonics": ["push", "mov", "sub"], "note": "function prologue"
}'

# Check a reconstructed routine actually computes what the model claimed:
reverify verify - --claim '{
  "kind": "emulate_result", "code": "b805000000b90300000001c8c3",
  "arch": "x86", "expect_registers": {"eax": 8}
}'

Claims can be batched from a JSON file (--claims-file claims.json); the CLI exits non-zero if anything is refuted, so an agent or CI job can gate on a grounded reconstruction. Claim kinds: bytes_at, u16_at / u32_at / u64_at (typed reads, no endianness math), pattern_present, string_present, instructions (mnemonics and optionally operands), emulate_result, behavior_equiv, prove_equiv, protobuf_field, import_present, export_present, section_present, and the semantic kinds function_at, calls, references, reachable_from_entry (see The semantic layer). Offsets are file offsets unless a claim says "space": "rva" or "va"; the verifier translates through the section table and echoes all three addresses in the evidence, and a refuted bytes_at reports where the expected bytes actually are. Set "observe": true (or omit expected) to have the tools read a value instead of asserting one, and "depends_on": [...] so a refuted root invalidates the claims built on it.

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