What is carbonado AGENTS.md?

A development guide for Carbonado, an archival format designed for durable, verifiable data storage, including Bitcoin-related data. It documents the current cryptographic design, streaming behavior, concurrency work, and important rules.

Use it when working on encryption, authentication, streaming, verification, error correction, sharding, or archive implementation details.

It records security-sensitive invariants and separates related concepts that could be confused when changing the format.

How bitmask-stack/carbonado configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to bitmask-stack/carbonado. 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/bitmask-stack/carbonado/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/bitmask-stack/carbonado

Made for: Codex, OpenCode.

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/bitmask-stack/carbonado/agents-md/github.svg)](https://agentmods.dev/instructions/bitmask-stack/carbonado/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/bitmask-stack/carbonado/agents-md"><img src="https://agentmods.dev/badge/instructions/bitmask-stack/carbonado/agents-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/bitmask-stack/carbonado/agents-md"><img src="https://agentmods.dev/badge/instructions/bitmask-stack/carbonado/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 19,385 This file is loaded in full into every session.

When invoked 19,385 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	$0.19385	$0.19385
Opus 5.5	$0.07754	$0.07754
Sonnet 5.5	$0.03877	$0.03877
Haiku 4.5	$0.01938	$0.01938

Measured 2mo ago against content hash eccb79c6cd2e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

carbonado AGENTS.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.

AGENTS.md · 982 lines

How it starts

The opening of the file, as written. The whole thing — 982 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md — Carbonado Development Guidelines

Project: Carbonado (bitmask-stack/carbonado)
Mission: Apocalypse-resistant archival format for consensus-critical data, with a focus on Bitcoin quantum resistance.
Current Status (as of 2026-07): Symmetric v2 stack (CARBONADO20\n, AES-256-CTR + HMAC-SHA512 EtM) stable. P1: SLICE_LEN=4096, keyed 4 KiB Bao groups, seekable slice verify. P2: streaming-first encode/decode. P3: segment sharding. P4: Adamantine 1.0 directory archives (see §7.1). FEC: reed-solomon-erasure RS 4/8. Outboard + scrub complete.

Unified streaming stack (three independent axes — do not conflate):

Axis	Status
Streaming / memory	Phase 1 fused sync path shipped (`SeekableSpool`, streaming EtM, stripe FEC). M1: non-FEC verification (c6) uses `SeekWriteAt` (O(chunk) RAM); FEC verification retains O(FEC body) shard buffers under segment-wide RS geometry (`finish_into` avoids a second full logical `Vec`). Residuals: FEC O(segment body), O(sidecar) outboard verify, async encoded-body spool. See doc/STREAMING_PARALLELISM.md. Not the same as Bao slice/stream verification.
Concurrency	Phase 2 optional `async` / `stream_decode_async` (disk spool bridge; WASM `NotImplemented`).
Parallelism	Phase 3 `parallel` feature (default on): `std::thread::scope` RS parity; WASM serial at runtime. No rayon; Tokio is not the CPU-parallel story.

PQC: bitcoinpqc 0.4, SLH-DSA-SHA2-128s sidecars only (SLH_DSA_SHA2_128S). Dev SHAKE-128s sidecars are incompatible — re-sign.

1. Core Principles

Clean cryptographic break. This version of Carbonado does not contain any code to read or write v1 ECIES-encrypted files. Old encrypted archives require external migration (use an older version of the tool to extract plaintext, then re-encode with the new symmetric primitives).
"Backward compatibility / migration path" (from the original spec) refers only to preserving the non-crypto properties of the format:
- Pipeline ordering (compress(zstd-20) → encrypt → FEC → bao and reverse)
- Flat-file portability
- WASM/browser support
- Bao-based streaming verification and replication proofs
- Forward error correction (4/8 RS model — see v1-vs-v2 rationale)
- Content addressability via the outer bao hash
First-principles security. All cryptographic decisions must be justifiable from security definitions (IND-CPA for CTR, INT-CTXT for EtM, PRF properties of HMAC-SHA512, domain separation, key independence).
HMAC-SHA512 is mandatory for both authentication (full 64-byte tags) and all subkey derivation. No simple splits, no SHA-256-only KDFs for key material.

Read the full file on GitHub · 982 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 · 982 lines · 19,385 tokens per session scan A eccb79c6cd2e

Subscribe to this mod's changes

carbonado AGENTS.md is an instructions file published in the GitHub repository bitmask-stack/carbonado (119 stars, last pushed 2mo ago), licensed MIT. It adds 19,385 tokens to every session, about $0.0775 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.

carbonado AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
carbonado AGENTS.mdbitmask-stack/carbonado	Instructions file	119	2mo ago	MIT	A	19,385	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	9,719	GitHub Copilot
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	5,516	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	today	MIT	A	4,680	Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode model-prompts.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	2,022	GitHub Copilot

carbonado: Instructions file for Codex