What is asm-assemble?

A tool that turns assembly text into machine-code bytes for x86, x64, ARM, or ARM64 processors using clang’s built-in assembler. The result can be shown as hexadecimal text, a C byte array, raw bytes, or JSON.

Use it to assemble code from a file or command line, extract its code bytes, prepare shellcode-style byte arrays, or pass the result to a separate emulator for testing.

It removes the need to write or configure a complete native program when you only need the bytes produced by an assembly snippet. The bytes are generated but not run on the host machine.

asm-assemble — Skill for Claude Code and Codex by batteryshark: A tool that turns assembly text into machine-code bytes…

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add skills/batteryshark/rekit/asm-assemble

Any agent

npx skills add batteryshark/rekit --skill asm-assemble

Clone the repo

git clone --depth 1 https://github.com/batteryshark/rekit

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/batteryshark/rekit/asm-assemble.svg)](https://agentmods.dev/skills/batteryshark/rekit/asm-assemble)

Your own site

<a href="https://agentmods.dev/skills/batteryshark/rekit/asm-assemble"><img src="https://agentmods.dev/badge/skills/batteryshark/rekit/asm-assemble.svg" alt="Measured on agentmods" height="20"></a>

Per session 104 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 598 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5	$0.00104	$0.00598
Opus 5	$0.00052	$0.00299
Sonnet 5	$0.00021	$0.00120
Haiku 4.5	$0.00010	$0.00060

Measured 5d ago against content hash f04261908eba, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

asm-assemble scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/run.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/asm-assemble/SKILL.md · 48 lines

What it actually says

Assembler (LLVM/clang)

🔨 Construct tier — produces bytes, runs nothing.

Role in the workflow

The write-side partner of emulate-code. Where that skill runs bytes on a virtual CPU, this one makes them: assemble a snippet, then emulate it — a tight write-shellcode → observe-behavior loop with no host execution at any point.

What it does

Assembles asm text (a file or --code "…") with the LLVM/clang integrated assembler for x64 / x86 / arm64 / arm, then extracts the raw .text bytes, emitted as:

hex (default) — a hex string
c — a ready-to-paste unsigned char shellcode[] = { … }; array (drop into a cc-build stub)
raw — the raw bytes (to --out, or stdout)
json — {ok, arch, triple, length, hex, out?}

x86/x64 default to Intel syntax (--att for AT&T/GAS); ARM uses GAS syntax.

Toolchain choice

The LLVM assembler supports the target architectures anywhere clang runs. keystone-engine has no arm64 macOS wheel, which would make that alternative platform-dependent.

Prerequisites

clang — xcode-select --install (macOS) or install clang/LLVM (Linux).
A section extractor — otool (ships with Xcode CLT) on macOS, or objcopy/llvm-objcopy/objdump on Linux. Checked flexibly; absent → honest hint.

Usage — the shellcode loop

rekit run asm-assemble --code "mov rax, 0x1337; mov [rsp], rax" --out sc.bin
rekit run emulate-code sc.bin            # ← run what you just assembled, contained
rekit run asm-assemble --code "mov x0, #0x1337" --arch arm64 --format hex
rekit run asm-assemble --code "xor eax,eax; ret" --arch x86 --format c   # C array for a stub

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

scripts/run.py 6.9 KB runs code

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

5d ago First seen · 48 lines · 104 tokens per session scan A f04261908eba

Subscribe to this mod's changes

asm-assemble is a skill published in the GitHub repository batteryshark/rekit (11 stars, last pushed 26d ago), licensed Apache-2.0. It adds 104 tokens to every session and 598 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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