What is zapcode CLAUDE.md?

Project-specific instructions for an AI coding assistant working on Zapcode, a project that parses TypeScript, compiles it to bytecode, and runs it in a virtual machine. It also defines where key parts of the codebase are located and which safety rules to follow.

Use it to orient work on parsing, the intermediate representation, compilation, bytecode, the virtual machine, and snapshots. It also sets a required reading order and a Git commit rule.

It gives the assistant the project’s architecture and security constraints before it changes code, reducing the risk of violating important sandbox rules.

How TheUncharted/zapcode configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to TheUncharted/zapcode. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/TheUncharted/zapcode/develop/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/TheUncharted/zapcode

Made for: Claude Code.

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/instructions/theuncharted/zapcode/claude-md/github.svg)](https://agentmods.dev/instructions/theuncharted/zapcode/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/theuncharted/zapcode/claude-md"><img src="https://agentmods.dev/badge/instructions/theuncharted/zapcode/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/theuncharted/zapcode/claude-md"><img src="https://agentmods.dev/badge/instructions/theuncharted/zapcode/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,620 This file is loaded in full into every session.

When invoked 1,620 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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 5.1	$0.01620	$0.01620
Opus 5.5	$0.00648	$0.00648
Sonnet 5.5	$0.00324	$0.00324
Haiku 4.5	$0.00162	$0.00162

Measured 2mo ago against content hash 23d109e202e5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

zapcode CLAUDE.md 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 2mo ago.

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.

CLAUDE.md · 188 lines

How it starts

The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

AI coding assistant instructions for the zapcode project. See AGENTS.md for the full architecture reference. This file adds Claude-Code-specific guidance on top of it.

Git

Do not add Co-Authored-By trailers to git commits.

Read AGENTS.md first

Before writing any code in this repository, read AGENTS.md in full. It defines:

What Zapcode is and what it must never do
The full architecture (parser → IR → bytecode → VM → snapshot)
The five sandbox invariants that must never be violated
The definition of "done" for any feature

Do not skip this. The sandbox invariants in particular will save you from introducing security vulnerabilities that are hard to detect and easy to ship.

Codebase orientation

Start here when working on a new area:

Area	Entry point
Parsing TypeScript	`crates/zapcode-core/src/parser/mod.rs`
IR definition	`crates/zapcode-core/src/parser/ir.rs`
Bytecode instructions	`crates/zapcode-core/src/compiler/instruction.rs`
Compiler (IR → bytecode)	`crates/zapcode-core/src/compiler/mod.rs`
VM main loop + dispatch	`crates/zapcode-core/src/vm/mod.rs`
Built-in functions	`crates/zapcode-core/src/vm/builtins.rs`
Value / type system	`crates/zapcode-core/src/value.rs`
Snapshot / resume	`crates/zapcode-core/src/snapshot.rs`
Resource limits	`crates/zapcode-core/src/sandbox.rs`
Error types	`crates/zapcode-core/src/error.rs`
JS bindings API	`crates/zapcode-js/src/lib.rs`
Python bindings API	`crates/zapcode-py/src/lib.rs`
WASM bindings API	`crates/zapcode-wasm/src/lib.rs`

When in doubt about where something belongs: zapcode-core is pure Rust with zero I/O. Bindings crates only translate types and marshal calls into zapcode-core. Never put business logic in binding crates.

How to add a new language feature

Check the supported subset table in AGENTS.md first. If the feature is explicitly listed as unsupported, do not add it without opening a discussion. Features are excluded intentionally.

Read the full file on GitHub · 188 lines

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.

2mo ago First seen · 188 lines · 1,620 tokens per session scan A 23d109e202e5

Subscribe to this mod's changes

zapcode CLAUDE.md is an instructions file published in the GitHub repository TheUncharted/zapcode (95 stars, last pushed 2mo ago), licensed MIT. It adds 1,620 tokens to every session, about $0.0065 per session on Opus 5.5. 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.

LLM agent ai ai-agents code-execution interpreter

zapcode CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
zapcode CLAUDE.mdTheUncharted/zapcode	Instructions file	95	2mo ago	MIT	A	1,620	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

zapcode: Instructions file for Claude Code