# The Permanent Record — Bitcoin OP_RETURN Monitor

> opreturn.xyz is a real-time, high-availability monitor and historical archive for arbitrary data and messages embedded inside the Bitcoin blockchain via OP_RETURN outputs. It tracks active bulletin boards, hacker communications, dormant wallet notices, and cultural memorials, with AI categorization and high-performance edge caching.

## What is Bitcoin OP_RETURN?

- **Opcode Mechanics**: `OP_RETURN` (`0x6a`) is a script opcode that marks a transaction output as provably unspendable.
- **UTXO Set Health**: Because provably unspendable outputs can never be spent, compliant nodes immediately prune them from their RAM-resident UTXO (Unspent Transaction Output) set, eliminating UTXO bloat while permanently committing the data to the blockchain history.
- **Data Limits**: Standard relay policy historically capped OP_RETURN data at 40 bytes (2014) and 80 bytes (2016). In 2025, Bitcoin Core v30 removed the default 80-byte relay cap (`-datacarriersize`), enabling standard propagation of larger arbitrary data payloads and multi-output data chaining.
- **Cost**: Embedding data requires paying miner fees proportional to transaction virtual size (vBytes), with output value typically set to 0 sats.
- **Immutability**: Once confirmed inside a Bitcoin block, transmissions are mathematically unalterable, uncensorable, and permanently replicated across tens of thousands of nodes worldwide.

## Monitored Collections & On-Chain Phenomena

The archive focuses on addresses that have evolved into public bulletin boards:
1. **Liquid Network Peg-Out Bulletin Board**: Addresses from the September 2026 Liquid Network whitehat incident (~3,996 BTC peg-out negotiation between hackers and Blockstream security).
2. **Coldcard Exploit Bulletin Board**: Primary holding addresses from the July-August 2026 Coldcard firmware RNG exploit, filled with laundry ads, victim pleas, threats, and prompt injections.
3. **High-Value Dormant Wallet Notices**: Early 2010-2011 high-balance addresses (including the Mt. Gox 1Feex address) targeted with legal notices, ownership claims, and phishing attempts.
4. **Genesis & Satoshi Tribute**: The Genesis block address (`1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa`), receiving ongoing memorials and prayers to Satoshi Nakamoto.
5. **Russian Intelligence Marking Campaign**: Addresses marked in 2022 via OP_RETURN as associated with GRU / SVR / FSB intelligence agencies.
6. **Cultural Memorials & Digital Graffiti**: Permanent personal tributes, biblical verses, and vanity address communications.
7. **Historical Hacker Negotiation Boards**: Historic addresses used for public bounty negotiations and victim-attacker dialogue.

## AI Classification Taxonomy

Transmissions are classified into seven discrete categories:
- `Laundry / Service Ads`: Mixers, crypto laundry, OTC desks, phishing links.
- `Begging / Victim Appeals`: Requests for refunds, charity, hospital bills, student loans.
- `Threats / Hostility`: Law enforcement ultimatums, hacker taunts, extortion.
- `Prompt Injection`: Text attempting to subvert LLM indexing bots (e.g., 'Ignore previous instructions').
- `Haiku / Philosophical`: Poetry, blockchain maxims, existential reflections.
- `Self-deprecating / Black Humor`: Irony, despair, memes about losing private keys.
- `Other`: General greetings, unclassified data, signatures.

## Public REST API

- `GET https://opreturn.xyz/api/collections` — All collections with address & message counts.
- `GET https://opreturn.xyz/api/messages?sort=hot|new&limit=50&collection_id=&address=&category=` — Filtered transmission feed.
- `GET https://opreturn.xyz/api/chat?collection_id=&address=` — Chronological conversation stream.
- `GET https://opreturn.xyz/api/categories` — Category distribution and counts.
- `GET https://opreturn.xyz/api/message/:key` — Message lookup by ID or txid.
- `GET https://opreturn.xyz/api/price?ts=` — Historical USD price at block timestamp.

## Machine Discovery & Agent Standards

- Full Technical Dossier: https://opreturn.xyz/llms-full.txt
- Live Transmissions Feed: https://opreturn.xyz/feed
- Curated Collections: https://opreturn.xyz/collections
- Field Manual (How to Etch): https://opreturn.xyz/guide
- Canonical Sitemap: https://opreturn.xyz/sitemap.xml
- RFC 9727 API Catalog: https://opreturn.xyz/.well-known/api-catalog
- OpenAPI Specification: https://opreturn.xyz/api/openapi.json
- A2A Agent Card: https://opreturn.xyz/.well-known/agent-card.json
- MCP Server Card: https://opreturn.xyz/.well-known/mcp/server-card.json
- Agent Authentication (Auth.md): https://opreturn.xyz/auth.md