reverse-engineering-anything/docs/guides/evm/evm-bytecode.md

# Offline EVM bytecode

`inspect_evm_interface` / `inspect-evm-interface` infers interface candidates
from one explicitly selected local bytecode carrier. The capability is general:
contract investigation, compatibility, audit and CTF showcases use the same
portable primitive. It does not require an active native binary target.

```sh
rea inspect-evm-interface ./runtime.hex hex --json
rea inspect-evm-interface ./runtime.bin raw --json
```

```json
{
  "name": "inspect_evm_interface",
  "arguments": { "path": "/artifacts/runtime.hex", "encoding": "hex" }
}
```

Initial real verification covers flat legacy bytecode on Linux x64 and unchanged
bundled EVMole 0.9.3. EOF-style EF00 containers return `unsupported_target`,
with the selected path and format reason. Selected-path resolution errors
`ENOENT`, `ENOTDIR`, `ELOOP`, and `ENAMETOOLONG` are `invalid_request` path
issues. Permission, resource, cancellation, provider, and cleanup failures retain
their distinct classifications.
The host must already provide util-linux `prlimit`, normally `/usr/bin/prlimit`;
`REA_EVM_PRLIMIT_COMMAND` can select another absolute executable. REA installs
no system tools and changes no user configuration. [Upstream provenance and
license](https://github.com/morluto/rea/blob/main/third_party/evmole/README.md) are packaged.

Limiter discovery validates the selected path without launching it. A relative
path or directory is reported as `not_configured`, a missing file as
`executable_missing`, and denied access or another filesystem-probe failure as
`runtime_unavailable`. Recovery names the selected path and
`REA_EVM_PRLIMIT_COMMAND`; denied access asks for execute permission and
filesystem access. The original admission or system code stays in diagnostics.
An available filesystem probe does not verify the selected tool's version or
util-linux compatibility, and REA does not substitute another command.

## Evidence semantics

- `encoding` is required: raw bytes or UTF-8 hex, with optional `0x` prefix and
  outer ASCII whitespace. Odd hex, interior separators, BOM, non-ASCII whitespace
  and invalid UTF-8 are rejected. Empty bytecode is valid and has unknown coverage.
- Carrier SHA-256 identifies the exact original file, including prefix/casing
  and whitespace. Decoded-byte SHA-256 identifies actual selected EVM bytes.
  Neither digest is the Ethereum Keccak code hash.
- Full bytecode, upstream function offsets and original producer representation
  are returned inline by default. Offsets are byte positions in decoded bytecode.
- Upstream also returns terminal metadata during selector recovery. Its reported
  values remain in `raw_result`; integer precision and non-text-key coverage are
  unknown in the JS binding. Full bytecode retains the original encoded metadata.
- `bytecode.metadata` independently interprets a plausible terminal CBOR root
  map from the selected bytes. Integers use decimal strings; byte strings use hex,
  and scalar keys retain their types. The recorded offset/length addresses the
  original bytecode, so summary delivery does not copy an opaque CBOR payload.
  Nested containers have partial scalar coverage; map keys are still checked for
  duplicates throughout nested maps and arrays. Unsupported or malformed
  candidates report `not-decoded` with a diagnostic. Decoding is bounded to 64
  container levels and the terminal payload's encoded size.
- An unavailable trailer does not prove metadata absence or Solidity origin.
  Compiler-version bytes/text are metadata declarations, not verified compiler,
  source-file or deployed-contract identity. Historical omission parses as a null
  unknown facet without changing the original Evidence record. Metadata/source
  URLs are not fetched.
- Selectors, argument strings and state mutability are **inferences**. Function
  names/signatures are not looked up. Optimized code may produce different
  mutability candidates; recovered types are not a verified source ABI.
- Runtime/init-code identity, deployed authenticity, hardfork and discovery
  completeness remain unknown. Empty candidates do not prove no callable interface.
- Analysis is offline: no target runtime execution, implicit chain/RPC/explorer
  lookup, wallet action, transaction broadcast or network request.

## Selected interface delivery and retained views

Existing CLI calls and MCP calls with omitted or `complete` detail keep the
complete inline result. On a retaining MCP server, select `detail: "summary"`
when the question needs every inferred function and its identity/uncertainty,
without bytecode text or duplicated raw stdout:

```json
{
  "name": "inspect_evm_interface",
  "arguments": {
    "path": "/artifacts/runtime.hex",
    "encoding": "hex",
    "detail": "summary"
  }
}
```

The result is distinct view Evidence linked to its complete parent. Like the
parent, it has `confidence: inferred`; projection never strengthens inferred
candidates. Its `normalized_result.summary` preserves every producer-returned
selector, decoded
byte offset, dispatch, argument/mutability string including null, carrier/decoded
identities, original limitations and explicit unknowns. Payload `evidence_kind`
remains `inferred`. It preserves stderr/truncation and records stdout text length.
Complete-within-view coverage covers returned candidates; discovery completeness
remains unknown even for an empty or exhausted collection. Analysis still runs;
delivery selection does not save interpreter work or change source parameters.

Use `normalized_result.parent_evidence_id` with `inspect_analysis_view` source
kind `retained-evidence`. EVM view kind `evm` pages `functions` by original row
order, or `bytecode_hex`, `stdout`, `stderr` by UTF-16 code units. Hex pages preserve
the original lowercase text without a prefix; two characters represent one decoded
byte. A text-page offset differs from a function's decoded-byte offset. Complete
parent Evidence remains accessible through the normal ledger/export workflow;
reading views does not rerun analysis or change its identity. Existing record
retention and close semantics are unchanged.

Portable historical complete EVM Evidence can use source kind `inline` without
a provider. A fixed server without Evidence retention rejects selected summary
delivery before starting analysis and continues to support complete delivery.
Discover the actual advertised schema before sending `detail` to an older server;
use its complete operation when an equivalent workflow is required. The one-shot
CLI keeps its existing complete result.

## Resource and lifecycle limits

Per-call `producer_limits` selects `input_bytes`, `output_bytes`,
`diagnostic_bytes`, `address_space_bytes`, `file_bytes` and `cpu_seconds`.
Omission keeps 4 MiB input, 16 MiB reply/file, 1 MiB diagnostics, 3 GiB address
space and 30 CPU seconds. Omitted `file_bytes` follows the selected
`output_bytes`, so raising the reply allowance does not silently meet the old
file-write allowance. Explicit file limits remain independent. These fields
accept positive safe integers; changes apply to the next call without a REA
restart. The CLI accepts the same exact policy as JSON, for example:

```sh
rea inspect-evm-interface ./runtime.hex hex --producer-limits '{"input_bytes":8388608,"output_bytes":33554432}'
```

The owned worker's 256 MiB JavaScript heap remains separate. The worker command
deadline is `timeout_ms` (default 30000 ms, integer 1 through 2147483647), or
`--timeout-ms` on the CLI. Raising it does not raise producer, heap or client
limits. An oversized carrier reports non-retryable `resource_constraint` with
`reported_limits.maximum_input_bytes` and recovery naming
`producer_limits.input_bytes`.
Complete-reply allowance refusals use the same non-retryable resource family,
with `reported_limits.maximum_reply_bytes`; malformed JSON remains unreadable
output. This refusal leaves no complete report to retrieve through another
delivery channel. Virtual address space differs from resident memory. The worker retains inherited tighter
soft/hard limits, reports its configured soft limits inline and leaves hard limits
unchanged. WASM trap reservations are disabled
so the engine can run within that virtual limit; actual memory is not equated to
the selected address-space allowance. Limits fail without partial success. Stable snapshots,
private files and owned processes are cleaned independently of caller cancellation.
Invalid-input, unsupported, cancellation, timeout and malformed-reply failures
retain bounded stdout/stderr under `details.captured_output`, including whether
diagnostic output was truncated. Cleanup failures preserve the
original error projection and any captured output.
Successful results expose `diagnostics.truncated` from the supervisor as well.
Excess diagnostic output fails the complete-output contract even when the worker
has written a valid reply.
SIGXCPU retains a CPU resource diagnostic and CPU-specific guidance. Observed
file-size write failures (EFBIG) and SIGXFSZ likewise retain a file-size resource
diagnostic. Exact signal/write causes remain unknown. Configured
soft limits are reported separately from unknown effective limits; the received
signal alone does not establish its exact cause.
Reserved file-size exits require a matching private marker written by the
worker's EFBIG branch. Bare launcher exits or unwritable markers retain process
diagnostics with the resource cause unverified.

Source/metadata, proxy resolution, storage/CFG and fork-explicit execution/traces
remain separate increments under #972, with materially different result or
execution authority. This primitive makes no deployment or runtime behavior claim.

The real verification lane traces representative raw/hex CLI workflows and checks
that only declared Node/prlimit launchers and process ownership inspection run.
Socket traces permit local stdio socket pairs and reject attempted network requests.
These observations verify those fixtures; they are not a general network sandbox.

For the independent metadata parser, `npm run verify:solidity:metadata` uses an
existing caller-selected solc 0.8.30 module:

```sh
REA_VERIFY_SOLC_MODULE=/absolute/path/to/solc/index.js npm run verify:solidity:metadata
```

It compiles the owned fixture with unoptimized, viaIR, content-hash-free and
CBOR-free settings, verifies the observed trailer facts and reports local decode
timings. No contract is executed. This lane does not establish the complete
Linux EVM provider's CLI/MCP, resource-limit or cleanup behavior.