OPNet Development Skill

A comprehensive skill for building on OPNet – Bitcoin’s L1 consensus layer for trustless smart contracts.

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STOP – MANDATORY READING BEFORE ANY CODE

IF YOU WRITE CODE WITHOUT READING THE REQUIRED DOCS, YOU WILL CREATE BROKEN, EXPLOITABLE CODE.

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CRITICAL RULES FOR AI AGENTS

ABSOLUTE RULE – NO RAW JAVASCRIPT

NEVER write raw JavaScript. ALWAYS use:

• Frontend: TypeScript + Vite + npm packages
• Backend: TypeScript + Node.js + npm packages
• NO EXCEPTIONS. NOT EVEN FOR “QUICK EXAMPLES”.

DO NOT:

• Read a few files and then say “I have enough context”
• Read random skills or guidelines not listed for your project type
• Start writing code after skimming 2-3 files
• Assume you know OPNet patterns from other frameworks
• Skip files because they “seem similar” to ones you read
• Create zip files or deliverables WITHOUT running npm run lint and npm run typecheck
• Say “run npm run lint to verify” instead of ACTUALLY running it

YOU MUST:

• Read EVERY SINGLE FILE listed for your project type below
• Read them IN ORDER – later files depend on earlier ones
• Read the COMPLETE FILE, not just the first few sections
• ONLY read files listed in this skill – no random exploration
• Confirm you read all files before writing ANY code
• ACTUALLY RUN npm install, npm run lint, npm run typecheck, npm run build
• FIX ALL ERRORS before creating any deliverable (zip, PR, etc.)

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WHY THIS MATTERS

OPNet development has:

• Beta package versions that change frequently – guessing versions = build failures
• Strict TypeScript rules – violations = security vulnerabilities
• Platform-specific patterns – wrong patterns = exploits, gas attacks, data loss

Guidelines are SUMMARIES. The docs/ folder contains the ACTUAL implementation patterns.

Reading 3-4 files is NOT enough. You MUST read ALL files for your project type.

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MANDATORY READING ORDER BY PROJECT TYPE

For ALL Projects (Read First, Every Time)

Order	File	Why
1	docs/core-typescript-law-CompleteLaw.md	THE LAW – Type system rules, forbidden constructs, required patterns
2	guidelines/setup-guidelines.md	Package versions, tsconfig, ESLint configs

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For Smart Contracts (AssemblyScript)

Read ALL of these BEFORE writing contract code:

Order	File	Contains
1	docs/core-typescript-law-CompleteLaw.md	Type rules (applies to AS too)
2	guidelines/setup-guidelines.md	Package versions, asconfig.json
3	guidelines/contracts-guidelines.md	Summary of contract patterns
4	docs/contracts-btc-runtime-README.md	Runtime overview
5	docs/contracts-btc-runtime-getting-started-installation.md	Setup
6	docs/contracts-btc-runtime-getting-started-first-contract.md	Entry point, factory pattern
7	docs/contracts-btc-runtime-getting-started-project-structure.md	Directory layout
8	docs/contracts-btc-runtime-core-concepts-storage-system.md	Storage types, pointers
9	docs/contracts-btc-runtime-core-concepts-pointers.md	Pointer allocation
10	docs/contracts-btc-runtime-api-reference-safe-math.md	SafeMath (MANDATORY for u256)
11	docs/contracts-btc-runtime-gas-optimization.md	Gas patterns, forbidden loops
12	docs/contracts-btc-runtime-core-concepts-security.md	Security checklist

For OP20 tokens, also read:

• docs/contracts-btc-runtime-api-reference-op20.md
• docs/contracts-btc-runtime-contracts-op20-token.md

For OP721 NFTs, also read:

• docs/contracts-btc-runtime-api-reference-op721.md
• docs/contracts-btc-runtime-contracts-op721-nft.md

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For Frontend (React/Vite)

Read ALL of these BEFORE writing frontend code:

Order	File	Contains
1	docs/core-typescript-law-CompleteLaw.md	Type rules, forbidden constructs
2	guidelines/setup-guidelines.md	Package versions, vite config
3	guidelines/frontend-guidelines.md	Summary of frontend patterns
4	docs/core-opnet-README.md	Client library overview
5	docs/core-opnet-getting-started-installation.md	Installation
6	docs/core-opnet-getting-started-quick-start.md	Quick start
7	docs/core-opnet-providers-json-rpc-provider.md	Provider setup
8	docs/core-opnet-providers-internal-caching.md	Caching (MANDATORY)
9	docs/core-opnet-contracts-instantiating-contracts.md	Contract instances
10	docs/core-opnet-contracts-simulating-calls.md	Read operations
11	docs/core-opnet-contracts-sending-transactions.md	Write operations
12	docs/core-opnet-contracts-transaction-configuration.md	Transaction options
13	docs/core-transaction-transaction-factory-interfaces.md	Advanced TX params (fees, notes, anchors)
14	docs/clients-walletconnect-README.md	Wallet connection
13	docs/frontend-motoswap-ui-README.md	THE STANDARD – Reference implementation

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For Backend/API (Node.js)

Read ALL of these BEFORE writing backend code:

Order	File	Contains
1	docs/core-typescript-law-CompleteLaw.md	Type rules, forbidden constructs
2	guidelines/setup-guidelines.md	Package versions
3	guidelines/backend-guidelines.md	Summary of backend patterns
4	docs/core-opnet-backend-api.md	REQUIRED FRAMEWORKS – hyper-express, uWebSockets.js
5	docs/core-opnet-providers-json-rpc-provider.md	Provider setup
6	docs/core-opnet-providers-threaded-http.md	Threading (MANDATORY)
7	docs/core-opnet-providers-internal-caching.md	Caching (MANDATORY)
8	docs/core-opnet-contracts-instantiating-contracts.md	Contract instances
9	docs/core-opnet-contracts-sending-transactions.md	Sending transactions
10	docs/core-transaction-transaction-factory-interfaces.md	Advanced TX params (fees, notes, anchors)

FORBIDDEN FRAMEWORKS: Express, Fastify, Koa, Hapi, Socket.io – use hyper-express and uWebSockets.js only.

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For Plugins (OPNet Node)

Read ALL of these BEFORE writing plugin code:

Order	File	Contains
1	docs/core-typescript-law-CompleteLaw.md	Type rules, forbidden constructs
2	guidelines/setup-guidelines.md	Package versions
3	guidelines/plugin-guidelines.md	Summary of plugin patterns
4	docs/core-OIP-OIP-0003.md	PLUGIN SPECIFICATION – Full spec
5	docs/plugins-plugin-sdk-README.md	SDK reference
6	docs/plugins-opnet-node-README.md	Node integration

CRITICAL: You MUST implement onReorg() to handle chain reorganizations or your data will be inconsistent.

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For Unit Tests (TypeScript)

Read ALL of these BEFORE writing test code:

Order	File	Contains
1	docs/core-typescript-law-CompleteLaw.md	Type rules
2	guidelines/setup-guidelines.md	Package versions
3	guidelines/unit-testing-guidelines.md	Summary of test patterns
4	docs/testing-unit-test-framework-README.md	Framework overview
5	docs/testing-opnet-unit-test-README.md	Test setup
6	docs/testing-opnet-unit-test-docs-Blockchain.md	Blockchain mocking
7	docs/testing-opnet-unit-test-docs-ContractRuntime.md	Contract runtime

CRITICAL: Unit tests are TypeScript (NOT AssemblyScript). They have a SEPARATE package.json.

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For Generic Questions (Architecture, Concepts, Best Practices)

Read: guidelines/generic-questions-guidelines.md

For questions like:

• “How does OPNet work?”
• “Can OPNet survive 51% attacks?”
• “How does airdrop work on OPNet?”
• “What’s the difference between OPNet and Runes/Ordinals?”
• “Why can’t contracts hold BTC?”
• “What is transaction pinning?”

See the full guideline for complete topic mappings and what docs to read for each question type.

IMPORTANT: For conceptual questions, read the relevant docs/sections BEFORE answering. Do not guess or make assumptions about how OPNet works.

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For Security Auditing

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STOP – MANDATORY READING BEFORE ANY AUDIT

IF YOU AUDIT CODE WITHOUT READING THE REQUIRED DOCS, YOU WILL MISS CRITICAL VULNERABILITIES.

OPNet audits require understanding:

• AssemblyScript runtime internals – serialization, storage, cache coherence
• Bitcoin-specific attack vectors – transaction pinning, malleability, reorgs
• Critical vulnerability patterns – that standard audits miss completely

You MUST read guidelines/audit-guidelines.md COMPLETELY before auditing ANY code.

Skipping the audit guidelines = missing vulnerabilities. There are no shortcuts.

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DISCLAIMER (MANDATORY IN EVERY REPORT)

IMPORTANT DISCLAIMER: This audit is AI-assisted and may contain errors,
false positives, or miss critical vulnerabilities. This is NOT a substitute
for a professional security audit by experienced human auditors.
Do NOT deploy to production based solely on this review.
Always engage professional auditors for contracts handling real value.

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Mandatory Reading Order for Audits

Read ALL of these IN ORDER before starting ANY audit:

Order	File	Why Required
1	docs/core-typescript-law-CompleteLaw.md	Type rules that define secure code
2	guidelines/audit-guidelines.md	COMPLETE AUDIT GUIDE – vulnerability patterns, checklists, detection methods

Then read based on code type:

Code Type	Additional Required Reading
Smart Contracts	docs/contracts-btc-runtime-core-concepts-security.md, docs/contracts-btc-runtime-gas-optimization.md, docs/contracts-btc-runtime-api-reference-safe-math.md, docs/contracts-btc-runtime-types-bytes-writer-reader.md
DEX/Swap Code	This SKILL.md – CSV, NativeSwap, Slashing sections
Frontend	guidelines/frontend-guidelines.md
Backend	guidelines/backend-guidelines.md
Plugins	guidelines/plugin-guidelines.md – Reorg Handling section

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AUDIT VERIFICATION CHECKPOINT

BEFORE writing ANY audit findings, confirm:

• I have read guidelines/audit-guidelines.md completely
• I have read docs/core-typescript-law-CompleteLaw.md completely
• I have read ALL additional docs for this code type
• I understand the Critical Runtime Vulnerability Patterns section
• I understand serialization/deserialization consistency requirements
• I understand storage system cache coherence issues
• I understand Bitcoin-specific attack vectors (CSV, pinning, reorgs)

If you cannot check ALL boxes, GO BACK AND READ THE DOCS.

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Smart Contract Audit Checklist (Summary)

See guidelines/audit-guidelines.md for COMPLETE checklists with detection patterns.

Category	Check For
Arithmetic	All u256 operations use SafeMath (no raw +, -, *, /)
Overflow/Underflow	SafeMath.add(), SafeMath.sub(), SafeMath.mul(), SafeMath.div()
Access Control	onlyOwner checks, authorization on sensitive methods
Reentrancy	State changes BEFORE external calls (checks-effects-interactions)
Gas/Loops	No while loops, all for loops bounded, no unbounded iterations
Storage	No iterating all map keys, stored aggregates for totals
Input Validation	All user inputs validated, bounds checked
Integer Handling	u256 created via fromString() for large values, not arithmetic
Serialization	Write/read type consistency, sizeof() mapping correct
Cache Coherence	Setters load from storage before comparison
Deletion Markers	Storage deletion uses 32-byte EMPTY_BUFFER
Bounds Checking	>= not > for max index checks

TypeScript/Frontend/Backend Audit Checklist (Summary)

Category	Check For
Type Safety	No any, no non-null assertions (the ! operator), no @ts-ignore
Null Safety	Explicit null checks, optional chaining used correctly
BigInt	All satoshi/token amounts use bigint, not number
No Floats	No floating point for financial calculations
Caching	Provider/contract instances cached, not recreated
Input Validation	Address validation, amount validation, bounds checking
Error Handling	Errors caught and handled, no silent failures
Provider Type	Use JSONRpcProvider (WebSocketProvider is experimental)

Bitcoin-Specific Audit Checklist (Summary)

Category	Check For
CSV Timelocks	All swap recipient addresses use CSV (anti-pinning)
UTXO Handling	Proper UTXO selection, dust outputs avoided
Transaction Malleability	Signatures not assumed immutable before confirmation
Fee Sniping	Proper locktime handling
Reorg Handling	Data deleted/reverted for reorged blocks
P2WPKH	Only compressed pubkeys (33 bytes), reject uncompressed
Witness Script Size	Validate against 3,600 byte standard limit

DEX/Swap Audit Checklist (Summary)

Category	Check For
Reservation System	Prices locked at reservation, not execution
Slippage Protection	Maximum slippage enforced
Front-Running	Reservation system prevents front-running
Queue Manipulation	Slashing penalties for queue abuse
Partial Fills	Atomic coordination of multi-provider payments

Critical Runtime Vulnerability Patterns (Summary)

See guidelines/audit-guidelines.md for COMPLETE patterns with code examples.

ID	Vulnerability	Impact
C-07	Serialization Mismatch (write u16, read u32)	Data corruption
C-08	sizeof() bytes treated as bits	Truncated data
C-09	Signed/unsigned type confusion (i8 → u8)	Sign loss
C-10	Cache coherence (setter compares to unloaded cache)	Silent state corruption
C-11	Wrong deletion marker size	has() returns wrong result
C-12	Generic integer truncation (only reading first byte)	Data loss
H-06	Index out of bounds	Memory corruption
H-07	Off-by-one (> instead of >=)	Buffer overflow
H-08	Pointer collision (truncate without hash)	Storage overwrites
M-05	Taylor series divergence	Incorrect math

ALWAYS end audit reports with the disclaimer. NEVER claim the audit is complete or guarantees security.

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VERIFICATION CHECKPOINT

BEFORE writing ANY code, you MUST be able to answer:

1. What project type am I building? (Contract / Frontend / Backend / Plugin / Tests)

2. Did I read EVERY file listed for this project type?

   • List each file you read
   • If you cannot list them all, GO BACK AND READ

3. What are the exact package versions? (from guidelines/setup-guidelines.md)

   • If you don’t know, GO BACK AND READ

4. What constructs are FORBIDDEN?

   • any, non-null assertion operator, while loops in contracts, number for satoshis, etc.
   • If you can’t list them, GO BACK AND READ

5. What patterns are REQUIRED?

   • Caching, SafeMath, threading, etc.
   • If you can’t list them, GO BACK AND READ

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STOP – DO NOT PROCEED IF:

• ❌ You read fewer than 5 docs files
• ❌ You skipped any file in the mandatory reading list
• ❌ You read files not listed for your project type
• ❌ You cannot list the exact package versions
• ❌ You’re about to write “I have enough context” after reading 2-3 files

GO BACK AND READ ALL THE REQUIRED FILES. NO SHORTCUTS.

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CODE VERIFICATION ORDER (MANDATORY)

You MUST actually RUN these commands, not just mention them.

Step 1: Install Dependencies

npm install

• Run this FIRST before any other commands
• If package.json was created or modified, this is REQUIRED
• Do NOT skip this step

Step 2: Run Prettier

npm run format

• Formats all code consistently
• Run BEFORE linting to avoid formatting conflicts
• Do NOT skip this step

Step 3: Run ESLint

npm run lint

• MUST pass with zero errors
• If errors exist, FIX THEM before proceeding
• Do NOT say “you should run lint” – actually RUN IT

Step 4: Run TypeScript Check

npm run typecheck

• Or npx tsc --noEmit if no script exists
• MUST pass with zero errors
• Fix all type errors before proceeding

Step 5: Build

npm run build

• Only run AFTER format, lint, and typecheck pass
• For contracts: verify .wasm file is generated

Step 6: Run Tests

npm run test

• Or npx ts-node --esm tests/*.test.ts for unit tests
• All tests MUST pass
• If tests fail, FIX THE CODE

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STOP – YOU MUST ACTUALLY RUN THESE COMMANDS

• ❌ Do NOT just write “run npm run lint to verify”
• ❌ Do NOT skip steps because “it should work”
• ❌ Do NOT consider code complete without running ALL steps
• ✅ Actually execute each command
• ✅ Verify each command passes
• ✅ Fix any errors before proceeding to next step

If you wrote code but didn’t run these commands, YOUR TASK IS NOT COMPLETE.

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TASK COMPLETION CHECKPOINT

BEFORE considering ANY task complete, ask yourself these questions:

1. Have I performed all the steps required by the task?

   • Did I address everything the user asked for?
   • Did I miss any requirements?

2. Did I actually run the verification commands?

   • Did I run npm install? (REQUIRED if package.json exists/changed)
   • Did I run npm run format? (REQUIRED – Prettier formatting)
   • Did I run npm run lint? (REQUIRED – must pass with zero errors)
   • Did I run npm run typecheck or npx tsc --noEmit? (REQUIRED)
   • Did I run npm run build? (REQUIRED for deployable code)
   • Did I run npm run test? (REQUIRED if tests exist)
   • If ANY command failed, did I fix the errors?
   • “I should run lint” is NOT the same as actually running it

3. Did I review and reconsider my work?

   • Re-read what I produced – is it correct?
   • Did I make any assumptions that could be wrong?
   • Are there edge cases I didn’t consider?
   • Could my code/answer introduce bugs or vulnerabilities?
   • For smart contracts: SafeMath, bounds checking, access control, serialization
   • For TypeScript: type safety, null handling, caching patterns
   • For answers: Is the information accurate? Did I verify it?

4. Did I write complete, production-ready code?

   • NEVER add comments like “in a production environment, you would…”
   • NEVER add stubs, placeholders, or TODO comments
   • NEVER write partial implementations with “add your logic here”
   • If you can’t implement something fully, explain why and ask the user
   • All code must be ready to use immediately, not a starting point

5. Is it appropriate to adjust non-code files?

   • Did I update documentation if behavior changed?
   • Did I update config files if dependencies changed?

6. Should new tests be written?

   • If I added new functionality, are there tests for it?
   • Do the tests cover security patterns from the guidelines?

7. Is this just exploration/research?

   • If yes, tests, linting, and auditing are not required
   • Focus on providing accurate information

This self-reflection prevents incomplete work, missed requirements, and security vulnerabilities.

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PROJECT DELIVERY

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STOP – BEFORE CREATING ANY ZIP OR DELIVERABLE

You MUST run and PASS all verification commands BEFORE packaging:

# 1. Install dependencies
npm install

# 2. Format code
npm run format

# 3. Lint (MUST PASS)
npm run lint

# 4. TypeScript check (MUST PASS)
npm run typecheck
# OR: npx tsc --noEmit

# 5. Build (MUST SUCCEED)
npm run build

# 6. Tests (MUST PASS)
npm run test

If ANY command fails, DO NOT create the zip. Fix the errors first.

❌ FORBIDDEN: Creating zip without running verification commands ❌ FORBIDDEN: Saying “run npm run lint to verify” instead of actually running it ❌ FORBIDDEN: Skipping typecheck because “it should work”

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When creating zip files for delivery:

NEVER include:

• node_modules/ – recipient runs npm install
• build/ or dist/ – recipient runs npm run build
• .git/ – repository history
• .env – contains secrets

Correct zip command (only AFTER all checks pass):

zip -r project.zip . -x "node_modules/*" -x "build/*" -x "dist/*" -x ".git/*" -x "*.wasm" -x ".env"

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What is OPNet

OPNet is a Bitcoin L1 consensus layer enabling smart contracts directly on Bitcoin. It is:

• NOT a metaprotocol – It’s a full consensus layer
• Fully trustless – No centralized components
• Permissionless – Anyone can participate
• Decentralized – Relies on Bitcoin PoW + OPNet epoch SHA1 mining

Security Model

After 20 blocks, an epoch is buried deep enough that changing it requires rewriting Bitcoin history at millions of dollars per hour, making OPNet state more final than Bitcoin’s 6-confirmation security.

The checksum root for each epoch is a cryptographic fingerprint of the entire state. If even one bit differs, the checksum changes completely and proof fails, making silent state corruption impossible.

Key Principles

1. Contracts are WebAssembly (AssemblyScript) – Deterministic execution
2. NON-CUSTODIAL – Contracts NEVER hold BTC
3. Verify-don’t-custody – Contracts verify L1 tx outputs, not hold funds
4. Partial reverts – Only consensus layer execution reverts; Bitcoin transfers are ALWAYS valid
5. No gas token – Uses Bitcoin directly
6. CSV timelocks are MANDATORY – All addresses receiving BTC in swaps MUST use CSV (CheckSequenceVerify) to prevent transaction pinning attacks

Why OPNet Requires Consensus (Not Just Indexing)

OPNet is fundamentally different from indexer-based protocols like Runes, Ordinals/BRC-20, or Alkanes:

Protocol	State Consistency	Can Different Nodes Disagree?
Runes	Indexer-dependent	Yes – no consensus mechanism
BRC-20	Indexer-dependent	Yes – no consensus mechanism
Alkanes	Indexer-dependent	Yes – WASM is deterministic but no consensus
OPNet	Cryptographic consensus	No – proof-of-work + attestations enforce agreement

Why this matters: For applications requiring binding state consistency (like DEXs, escrows, or any multi-party coordination), indexer disagreement is catastrophic. When NativeSwap locks a reservation at a specific price, EVERY node must agree that reservation exists. OPNet’s consensus layer guarantees this through cryptographic proofs.

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CSV: The Critical Anti-Pinning Mechanism (MANDATORY)

What is Transaction Pinning?

Transaction pinning is a catastrophic attack vector that most Bitcoin protocols ignore. Here’s how it works:

1. When you send Bitcoin to someone, they can immediately create a transaction spending that Bitcoin, even before the first transaction is confirmed
2. An attacker creates massive chains of unconfirmed transactions, all dependent on each other
3. This makes it impossible for miners to include your legitimate transaction in a block
4. Your transaction is stuck in mempool limbo while the attacker manipulates contract state

Why Pinning Destroys DEXs Without Protection

Attack scenario on an unprotected DEX:

1. Attacker pins your swap transaction, preventing confirmation
2. Your reservation expires, but your BTC is stuck in mempool
3. Attacker cancels their sell orders or manipulates pool state
4. When your transaction finally confirms (if ever), no tokens remain
5. Result: Attacker gets free money, you lose everything

This vulnerability exists in every Bitcoin protocol that doesn’t mandate CSV:

• Multisig bridges can be frozen entirely with one malicious unwrap request
• Ordinals marketplaces are vulnerable
• Runes trading platforms are vulnerable
• BRC-20 exchanges are vulnerable

The CSV Solution

CSV (CheckSequenceVerify, BIP 112) completely eliminates pinning attacks:

Without CSV: Maximum unconfirmed chain length = UNLIMITED (attackers can pin forever)
With CSV:    Maximum unconfirmed chain length = ZERO (must wait for confirmation)

By requiring all seller addresses to have a 1-block CSV timelock, once Bitcoin arrives at those addresses, it cannot be spent again for at least one block. This is mathematically provable and completely closes the attack vector.

Implementation Requirement

ALL addresses receiving BTC in OPNet swaps MUST use CSV timelocks.

This is enforced at the protocol level in NativeSwap. If you’re building any application that coordinates BTC transfers with smart contract state, you MUST implement CSV protection.

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The Two Address Systems (CRITICAL for Airdrops)

Why OPNet Airdrops Work Differently Than Ethereum

On Ethereum, there’s one address format. You can loop through addresses and call transfer(to, amount) because ERC20 contracts just decrement sender balance and increment recipient balance using the same address type.

On OPNet, contract balances are keyed by ML-DSA public key hashes (32-byte quantum-resistant addresses), but users are typically known externally by their Bitcoin addresses (Taproot P2TR, tweaked public keys). These are completely different cryptographic systems with no inherent link between them.

Address System	Format	Used For
Bitcoin Address	Taproot P2TR (bc1p...)	External identity, what you have in your airdrop list
OPNet Address	ML-DSA public key hash (32 bytes)	Contract balances, internal state

WHY YOU CANNOT JUST LOOP AND TRANSFER

If you have a list of Bitcoin addresses from token holders or snapshot participants:

// WRONG - THIS DOES NOT WORK
for (const btcAddress of airdropList) {
    await token.transfer(btcAddress, amount);  // IMPOSSIBLE
}

The contract literally cannot credit tokens to a Bitcoin address directly. The contract storage uses ML-DSA addresses, not Bitcoin addresses. The mapping between them only exists once a user explicitly proves ownership of both keys together.

THE CORRECT SOLUTION: Claim-Based Airdrop Contract

Airdrops on OPNet are done via a smart contract with a claim pattern:

1. Deploy an airdrop contract that stores allocations keyed by tweaked public key:

// Contract storage
mapping(tweakedPubKey => amount)  // Store: which Bitcoin addresses get how much
mapping(tweakedPubKey => claimed) // Track: has this allocation been claimed

2. Users call claim() providing a signature that proves they control that Bitcoin address:

// User's frontend (browser) - OP_WALLET signs automatically
const message = `Claim airdrop for ${contractAddress}`;
const signed = await MessageSigner.tweakAndSignMessageAuto(message);

// Submit to contract with signature in calldata
await airdropContract.claim(signature, messageHash);

3. Contract verifies and transfers:

// Contract logic
public claim(calldata: Calldata): BytesWriter {
    const signature = calldata.readBytes(64);
    const messageHash = calldata.readBytes(32);

    // Verify signature proves caller owns the tweaked public key
    if (!Blockchain.verifySignature(Blockchain.tx.origin, signature, messageHash, false)) {
        throw new Revert('Invalid signature');
    }

    // Get allocation for this tweaked public key
    const tweakedKey = Blockchain.tx.origin.tweakedPublicKey;
    const amount = this.allocations.get(tweakedKey);

    // Transfer to caller's ML-DSA address (now linked!)
    this._mint(Blockchain.tx.sender, amount);
    this.claimed.set(tweakedKey, true);
}

This is the “unlock transaction” – the moment where the user proves ownership of both identities (Bitcoin address AND ML-DSA address), allowing the contract to link them and credit the tokens.

The Banana Locker Analogy

• You know 300 monkeys by their face (Bitcoin address)
• Lockers open with a secret handshake (ML-DSA key)
• You label lockers with faces and put bananas inside
• When a monkey shows up, they show face AND do handshake
• System learns: “this face = this handshake” and gives them their banana
• The banana was always “theirs” but they couldn’t access it until they linked face to handshake

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NativeSwap: How to Build a Real DEX on Bitcoin

NativeSwap answers the biggest unanswered question in BitcoinFi: How do you build an actual AMM that trades native BTC for tokens, trustlessly, without custody?

The Fundamental Problem

Traditional AMMs (like Uniswap) hold both assets in a pool and use math to set prices. Bitcoin cannot do this – you literally cannot have a smart contract hold and programmatically transfer BTC.

Why common “solutions” fail:

• Multisig wallets: Trusted parties can collude or disappear
• Wrapped BTC: Bridges become honeypots (billions stolen from bridges)
• Pure order books: Terrible liquidity without market makers holding inventory

Virtual Reserves: The Solution

NativeSwap realizes that an AMM doesn’t need to physically hold assets – it just needs to track the economic effect of trades. This is similar to:

• Banks updating ledger entries without moving physical cash
• Futures markets trading billions in commodities without touching a barrel of oil
• Clearinghouses settling trillions without holding underlying assets

How it works:

1. The contract maintains two numbers: bitcoinReserve and tokenReserve
2. When someone buys tokens with BTC, the system records that bitcoin reserve increased and token reserve decreased
3. The actual BTC goes directly to sellers, not to the contract
4. AMM pricing only depends on the ratio between reserves
5. The constant product formula (bitcoinReserve × tokenReserve = k) works identically whether reserves are physical or virtual

Two-Phase Commit: Why Reservations Are Necessary

Problem: OPNet can revert smart contract execution, but it cannot reverse Bitcoin transfers. Once you send BTC, that transfer is governed by Bitcoin’s consensus rules, not OPNet’s.

Catastrophic scenario without reservations:

1. You see token price is 0.01 BTC/token
2. You create a transaction sending 1 BTC to buy 100 tokens
3. During 10-20 minute confirmation time, other trades push price to 0.02 BTC/token
4. On Ethereum, your transaction would revert and return your ETH
5. On Bitcoin, your BTC transfer already happened – the contract can’t send it back
6. You lose your BTC and get zero tokens

The reservation system (two-phase commit):

Phase	What Happens
Phase 1: Reserve	Prove you control BTC (UTXOs as inputs, sent back to yourself), pay small fee, price is locked in consensus state
Phase 2: Execute	Send exact BTC amount to providers (up to 200 addresses atomically), guaranteed execution at locked price

Benefits:

• No slippage risk: Price locked at reservation time
• No front-running: Once price is locked in OPNet state, no one can change it
• Partial fills: Automatically coordinate payments to up to 200 providers in single atomic transaction (impossible on any other Bitcoin protocol)

Queue Impact: Accounting for Pending Sells

Sellers queue tokens at the prevailing AMM price. The Queue Impact mechanism adjusts effective token reserve using logarithmic scaling:

Why logarithmic?

• Markets process information multiplicatively
• Doubling queue from 100→200 tokens has same psychological impact as 1000→2000
• First sellers signal strong selling pressure; additional sellers have diminishing marginal impact
• Matches empirical observations from market microstructure research

Slashing: Making Queue Manipulation Economically Irrational

Without penalties, Queue Impact would be worthless:

1. Attacker adds massive fake sell orders → crashes price via Queue Impact
2. Attacker buys cheap tokens
3. Attacker cancels their sells
4. Profit from manipulation

The slashing mechanism:

• Immediate cancellation: 50% penalty (exceeds any realistic manipulation profit)
• Extended squatting: Escalates to 90% penalty
• Slashed tokens return to pool: Attempted attacks actually improve liquidity

This makes manipulation economically irrational and ensures queue depth is a reliable market signal.

Summary: Why Each Component Is Necessary

Component	Constraint It Addresses
Virtual reserves	Smart contracts can’t custody BTC on Bitcoin
Reservations (two-phase commit)	OPNet controls contract state, not Bitcoin transfers
Queue Impact	Pending orders affect market psychology and pricing
Slashing	Queue Impact would be manipulable without penalties
CSV timelocks	UTXO chains are vulnerable to transaction pinning
OPNet consensus	Indexers can’t provide binding state consistency

Remove any component and the system either becomes exploitable or stops functioning as an AMM.

---

ENFORCEMENT RULES (NON-NEGOTIABLE)

Before Writing ANY Code

YOU MUST:

1. READ docs/core-typescript-law-CompleteLaw.md COMPLETELY – These are strict TypeScript rules
2. VERIFY project configuration matches standards in docs/ config files

Configuration Files (in docs/)

File	Purpose
eslint-contract.json	ESLint for AssemblyScript contracts
eslint-generic.json	ESLint for TypeScript libraries
eslint-react.json	ESLint for React/Next.js frontends
tsconfig-generic.json	TypeScript config (NOT for contracts)
asconfig.json	AssemblyScript compiler config

TypeScript is MANDATORY – NO EXCEPTIONS

---

STOP – ABSOLUTE RULE

YOU MUST NEVER, EVER WRITE RAW JAVASCRIPT CODE. NO EXCEPTIONS.

---

All code MUST be TypeScript with proper tooling:

Project Type	Required Stack
Frontend	TypeScript + Vite + npm libraries
Backend	TypeScript + Node.js + npm libraries
Contracts	AssemblyScript (TypeScript-like)
Tests	TypeScript

FORBIDDEN – NEVER DO THESE:

• ❌ Raw JavaScript files – NEVER write .js source files
• ❌ Inline <script> tags – NEVER embed JS in HTML
• ❌ Browser-only JS – NEVER write code that only runs in browser console
• ❌ No build system – NEVER skip Vite/bundler for frontend
• ❌ // @ts-check in JS – This is NOT TypeScript, use real .ts files
• ❌ allowJs: true – NEVER enable this in tsconfig
• ❌ CDN script imports – Use npm packages instead

REQUIRED – ALWAYS DO THESE:

• ✅ All source files must be .ts or .tsx
• ✅ Use Vite for all frontend applications
• ✅ Use Node.js + TypeScript for all backend applications
• ✅ Install dependencies via npm (not CDN links)
• ✅ Strict mode enabled in tsconfig
• ✅ All types explicitly defined
• ✅ Proper project structure with package.json, tsconfig.json, etc.

If User Asks for “Quick Script” or “Simple Example”

STILL USE TYPESCRIPT. Create a proper project structure:

# Even for "quick" examples
mkdir project && cd project
npm init -y
npm install typescript tsx
# Write .ts file, run with npx tsx script.ts

There is NO scenario where raw JavaScript is acceptable.

---

Full Project Setup is MANDATORY

Before writing ANY code, the project MUST have:

project/
├── package.json          # With correct OPNet package versions
├── tsconfig.json         # Matching docs/tsconfig-generic.json
├── eslint.config.js      # Using appropriate config from docs/
├── .prettierrc           # Prettier configuration
├── .prettierignore       # Prettier ignore file
├── src/                  # Source code directory
│   └── index.ts          # Entry point
└── tests/                # Test directory (if applicable)
    └── *.test.ts

Prettier Configuration (MANDATORY)

.prettierrc:

{
    "semi": true,
    "singleQuote": true,
    "tabWidth": 4,
    "trailingComma": "all",
    "printWidth": 100,
    "bracketSpacing": true,
    "arrowParens": "always"
}

.prettierignore:

node_modules/
build/
dist/
*.wasm
coverage/

Package.json scripts (add these):

{
    "scripts": {
        "format": "prettier --write \"src/**/*.{ts,tsx}\"",
        "format:check": "prettier --check \"src/**/*.{ts,tsx}\""
    }
}

Run Prettier before committing:

npm run format

For Frontend (React/Vite), also include:

├── vite.config.ts        # Vite configuration
├── index.html            # Entry HTML
└── src/
    ├── App.tsx
    ├── main.tsx
    └── styles/           # CSS files (NO inline CSS)
        └── variables.css

For Contracts (AssemblyScript), also include:

├── asconfig.json         # AssemblyScript config
└── assembly/
    ├── index.ts          # Contract entry point
    └── contracts/
        └── MyContract.ts

You MUST create these files BEFORE writing application code.

---

Configuration Verification Checklist

• package.json exists with correct OPNet package versions
• tsconfig.json matches docs/tsconfig-generic.json (or strict ESNext for contracts)
• eslint.config.js uses appropriate config from docs/
• .prettierrc exists with correct configuration
• NO any type anywhere – This is FORBIDDEN
• NO inline CSS – Use CSS modules, Tailwind, or external stylesheets
• NO JavaScript files – TypeScript only
• Code is formatted with Prettier (npm run format)
• ESNext compliant
• Unit tests exist and pass

IF ANY CHECK FAILS → REFUSE TO CODE UNTIL FIXED

Misconfigured projects lead to exploits and critical vulnerabilities.

---

TypeScript Law (CRITICAL)

From docs/core-typescript-law-CompleteLaw.md:

FORBIDDEN Constructs

Construct	Why Forbidden
any	Runtime bug waiting to happen. No exceptions.
unknown	Only at system boundaries (JSON parsing, external APIs)
object (lowercase)	Use specific interfaces or Record<string, T>
Function (uppercase)	Use specific signatures
{}	Means “any non-nullish value”. Use Record<string, never>
Non-null assertion (the ! operator)	Use explicit null checks or optional chaining
Dead/duplicate code	Design is broken if present
ESLint bypasses	Never
Section separator comments	See below
Inline CSS	Use CSS modules, styled-components, or external stylesheets. No style={{ }} props.

FORBIDDEN: Section Separator Comments

NEVER write comments like:

// ==================== PRIVATE METHODS ====================
// ---------------------- HELPERS ----------------------
// ************* CONSTANTS *************
// ####### INITIALIZATION #######

These are lazy, unprofessional, and useless. They add noise without value.

INSTEAD: Use proper TSDoc for EVERY class, method, property, and function:

/**
 * Transfers tokens from sender to recipient.
 *
 * @param to - The recipient address
 * @param amount - The amount to transfer in base units
 * @returns True if transfer succeeded
 * @throws {InsufficientBalanceError} If sender has insufficient balance
 * @throws {InvalidAddressError} If recipient address is invalid
 *
 * @example
 * ```typescript
 * const success = await token.transfer(recipientAddress, 1000n);
 * ```
 */
public async transfer(to: Address, amount: bigint): Promise<boolean> {
    // ...
}

TSDoc Requirements:

• @param for every parameter
• @returns for non-void returns
• @throws for possible exceptions
• @example for non-trivial methods
• Description of what the method does, not how

Code organization comes from proper class design, not ASCII art.

Numeric Types

• number: Array lengths, loop counters, small flags, ports, pixels
• bigint: Satoshi amounts, block heights, timestamps, database IDs, file sizes, cumulative totals
• Floats for financial values: FORBIDDEN – Use fixed-point bigint with explicit scale

Common API Pitfalls

Address.fromString() requires TWO parameters:

// WRONG - will fail
const addr = Address.fromString(addressString);

// CORRECT - always provide both params
const addr = Address.fromString(mldsaPublicKey, tweakedPublicKey);

The first parameter is the ML-DSA public key (quantum-resistant), the second is the tweaked public key (legacy Bitcoin). Always provide both.

Required tsconfig.json Settings

{
    "compilerOptions": {
        "strict": true,
        "noImplicitAny": true,
        "strictNullChecks": true,
        "noUnusedLocals": true,
        "noUnusedParameters": true,
        "exactOptionalPropertyTypes": true,
        "noImplicitReturns": true,
        "noFallthroughCasesInSwitch": true,
        "noUncheckedIndexedAccess": true,
        "noImplicitOverride": true,
        "moduleResolution": "bundler",
        "module": "ESNext",
        "target": "ESNext",
        "lib": ["ESNext"],
        "isolatedModules": true,
        "verbatimModuleSyntax": true
    }
}

---

Performance Rules

THREADING IS MANDATORY

• Sequential processing = unacceptable performance
• Use Worker threads for CPU-bound work
• Use async with proper concurrency for I/O
• Batch operations where possible
• Use connection pooling

Caching (ALWAYS)

• Reuse contract instances – Never create new instances for same contract
• Reuse providers – Single provider instance per network
• Cache locally – Browser localStorage/IndexedDB for user data
• Cache on API – Server-side caching for blockchain state
• Invalidate on block change – Clear stale data when new block confirmed

RPC Call Optimization

Use .metadata() instead of multiple calls:

// ❌ BAD - 4 RPC calls (slow)
const [name, symbol, decimals, totalSupply] = await Promise.all([
    contract.name(),
    contract.symbol(),
    contract.decimals(),
    contract.totalSupply()
]);

// ✅ GOOD - 1 RPC call (fast)
const { name, symbol, decimals, totalSupply } = (await contract.metadata()).decoded;

.metadata() returns name, symbol, decimals, totalSupply, owner, and more in ONE call.

Backend/API Frameworks

MANDATORY: Use OPNet’s high-performance libraries:

Package	Purpose
@btc-vision/uwebsocket.js	WebSocket server (fastest)
@btc-vision/hyper-express	HTTP server (fastest)

FORBIDDEN: Express, Fastify, Koa, Hapi, or any other HTTP framework. They are significantly slower.

// CORRECT - Use hyper-express with threading
import HyperExpress from '@btc-vision/hyper-express';
import { Worker } from 'worker_threads';

const app = new HyperExpress.Server();
// Use classes, not functions
// Delegate CPU work to workers

---

Contract Gas Optimization (CRITICAL)

FORBIDDEN Patterns in Contracts

Pattern	Why Forbidden	Alternative
while loops	Unbounded gas consumption	Use bounded for loops
Infinite loops	Contract halts, wastes gas	Always have exit condition
Iterating all map keys	O(n) grows exponentially	Use indexed lookups, pagination
Iterating all array elements	O(n) cost explosion	Store aggregates, use pagination
Unbounded arrays	Grows forever	Cap size, use cleanup

Gas-Efficient Patterns

// WRONG - Iterating all holders (O(n) disaster)
let total: u256 = u256.Zero;
for (let i = 0; i < holders.length; i++) {
    total = SafeMath.add(total, balances.get(holders[i]));
}

// CORRECT - Store running total
const totalSupply: StoredU256 = new StoredU256(TOTAL_SUPPLY_POINTER);
// Update on mint/burn, read in O(1)

---

Security Audit Checklist

All Code Must Be Checked For:

Cryptographic

• Key generation entropy
• Nonce reuse
• Signature malleability
• Timing attacks
• Replay attacks

Smart Contract

• Reentrancy
• Integer overflow/underflow
• Access control bypass
• Authorization flaws
• State manipulation
• Race conditions

Bitcoin-specific

• Transaction malleability
• UTXO selection vulnerabilities
• Fee sniping
• Dust attacks
• Transaction pinning attacks – MUST use CSV timelocks
• Unconfirmed transaction chains – Verify CSV enforcement

DEX/Swap-specific

• Front-running / MEV attacks
• Price manipulation via queue flooding
• Reservation expiry edge cases
• Partial fill coordination
• Slashing mechanism bypass attempts

---

Quick Start

Task	Template
New OP20 token	templates/contracts/OP20Token.ts
New OP721 NFT	templates/contracts/OP721NFT.ts
Generic contract	templates/contracts/MyContract.ts
Contract tests	templates/tests/
Frontend dApp	templates/frontend/
Node plugin (indexer)	templates/plugins/OP20Indexer.ts
Node plugin (generic)	templates/plugins/MyPlugin.ts

---

Complete File Index

Configuration Files (docs/)

File	Description
docs/asconfig.json	AssemblyScript compiler config
docs/eslint-contract.json	ESLint for AssemblyScript contracts
docs/eslint-generic.json	ESLint for TypeScript libraries
docs/eslint-react.json	ESLint for React frontends
docs/tsconfig-generic.json	TypeScript config (not contracts)
docs/setup-README.md	Setup instructions

TypeScript Law

File	Description
docs/core-typescript-law-readme.md	Overview
docs/core-typescript-law-CompleteLaw.md	COMPLETE RULES – READ FIRST

OPNet Client Library

File	Description
docs/core-opnet-README.md	Library overview
docs/core-opnet-backend-api.md	Backend API with hyper-express
docs/core-opnet-getting-started-installation.md	Installation
docs/core-opnet-getting-started-overview.md	Architecture overview
docs/core-opnet-getting-started-quick-start.md	Quick start guide
docs/core-opnet-providers-json-rpc-provider.md	JSON-RPC provider
docs/core-opnet-providers-websocket-provider.md	WebSocket provider
docs/core-opnet-providers-understanding-providers.md	Provider concepts
docs/core-opnet-providers-advanced-configuration.md	Advanced config
docs/core-opnet-providers-internal-caching.md	Caching system
docs/core-opnet-providers-threaded-http.md	Threading
docs/core-opnet-contracts-overview.md	Contract interaction overview
docs/core-opnet-contracts-instantiating-contracts.md	Creating contract instances
docs/core-opnet-contracts-simulating-calls.md	Simulating calls
docs/core-opnet-contracts-sending-transactions.md	Sending transactions
docs/core-opnet-contracts-gas-estimation.md	Gas estimation
docs/core-opnet-contracts-offline-signing.md	Offline signing
docs/core-opnet-contracts-transaction-configuration.md	TX config
docs/core-opnet-contracts-contract-code.md	Contract code retrieval
docs/core-opnet-abi-reference-abi-overview.md	ABI overview
docs/core-opnet-abi-reference-data-types.md	ABI data types
docs/core-opnet-abi-reference-op20-abi.md	OP20 ABI
docs/core-opnet-abi-reference-op20s-abi.md	OP20S ABI (signatures)
docs/core-opnet-abi-reference-op721-abi.md	OP721 ABI
docs/core-opnet-abi-reference-motoswap-abis.md	MotoSwap ABIs
docs/core-opnet-abi-reference-factory-abis.md	Factory ABIs
docs/core-opnet-abi-reference-stablecoin-abis.md	Stablecoin ABIs
docs/core-opnet-abi-reference-custom-abis.md	Custom ABI creation
docs/core-opnet-api-reference-provider-api.md	Provider API
docs/core-opnet-api-reference-contract-api.md	Contract API
docs/core-opnet-api-reference-epoch-api.md	Epoch API
docs/core-opnet-api-reference-utxo-manager-api.md	UTXO Manager API
docs/core-opnet-api-reference-types-interfaces.md	Types & interfaces
docs/core-opnet-bitcoin-utxos.md	UTXO handling
docs/core-opnet-bitcoin-utxo-optimization.md	UTXO optimization
docs/core-opnet-bitcoin-balances.md	Balance queries
docs/core-opnet-bitcoin-sending-bitcoin.md	Sending BTC
docs/core-opnet-blocks-block-operations.md	Block operations
docs/core-opnet-blocks-block-witnesses.md	Block witnesses
docs/core-opnet-blocks-gas-parameters.md	Gas parameters
docs/core-opnet-blocks-reorg-detection.md	Reorg detection
docs/core-opnet-epochs-overview.md	Epochs overview
docs/core-opnet-epochs-epoch-operations.md	Epoch operations
docs/core-opnet-epochs-mining-template.md	Mining template
docs/core-opnet-epochs-submitting-epochs.md	Submitting epochs
docs/core-opnet-transactions-broadcasting.md	Broadcasting TXs
docs/core-opnet-transactions-fetching-transactions.md	Fetching TXs
docs/core-opnet-transactions-transaction-receipts.md	TX receipts
docs/core-opnet-transactions-challenges.md	TX challenges
docs/core-opnet-storage-storage-operations.md	Storage operations
docs/core-opnet-public-keys-public-key-operations.md	Public key ops
docs/core-opnet-utils-bitcoin-utils.md	Bitcoin utilities
docs/core-opnet-utils-binary-serialization.md	Binary serialization
docs/core-opnet-utils-revert-decoder.md	Revert decoder
docs/core-opnet-examples-op20-examples.md	OP20 examples
docs/core-opnet-examples-op721-examples.md	OP721 examples
docs/core-opnet-examples-deployment-examples.md	Deployment examples
docs/core-opnet-examples-advanced-swaps.md	Swap examples

Transaction Library

File	Description
docs/core-transaction-README.md	Library overview
docs/core-transaction-transaction-building.md	Building transactions
docs/core-transaction-transaction-factory-interfaces.md	TransactionFactory interfaces (fees, notes, anchors, send-max)
docs/core-transaction-offline-transaction-signing.md	Offline signing
docs/core-transaction-addresses-P2OP.md	P2OP address format
docs/core-transaction-quantum-support-README.md	Quantum overview
docs/core-transaction-quantum-support-01-introduction.md	Quantum intro
docs/core-transaction-quantum-support-02-mnemonic-and-wallet.md	Quantum wallet
docs/core-transaction-quantum-support-03-address-generation.md	Quantum addresses
docs/core-transaction-quantum-support-04-message-signing.md	Quantum signing
docs/core-transaction-quantum-support-05-address-verification.md	Quantum verification

Address Systems & Airdrops (CRITICAL)

File	Description
docs/core-opnet-address-systems-airdrop-pattern.md	Two address systems, airdrop pattern (MUST READ)

OIP Specifications

File	Description
docs/core-OIP-README.md	OIP overview
docs/core-OIP-OIP-0001.md	OIP process
docs/core-OIP-OIP-0002.md	Contract standards
docs/core-OIP-OIP-0003.md	Plugin system spec
docs/core-OIP-OIP-0004.md	Epoch system
docs/core-OIP-OIP-0020.md	OP20 token standard
docs/core-OIP-OIP-0721.md	OP721 NFT standard

Contract Runtime (btc-runtime)

File	Description
docs/contracts-btc-runtime-README.md	Runtime overview
docs/contracts-btc-runtime-gas-optimization.md	Gas optimization (CRITICAL)
docs/contracts-btc-runtime-getting-started-installation.md	Installation
docs/contracts-btc-runtime-getting-started-first-contract.md	First contract
docs/contracts-btc-runtime-getting-started-project-structure.md	Project structure
docs/contracts-btc-runtime-core-concepts-blockchain-environment.md	Blockchain env
docs/contracts-btc-runtime-core-concepts-storage-system.md	Storage system
docs/contracts-btc-runtime-core-concepts-pointers.md	Storage pointers
docs/contracts-btc-runtime-core-concepts-events.md	Events
docs/contracts-btc-runtime-core-concepts-decorators.md	Decorators
docs/contracts-btc-runtime-core-concepts-security.md	Security
docs/contracts-btc-runtime-api-reference-blockchain.md	Blockchain API
docs/contracts-btc-runtime-api-reference-storage.md	Storage API
docs/contracts-btc-runtime-api-reference-events.md	Events API
docs/contracts-btc-runtime-api-reference-op20.md	OP20 API
docs/contracts-btc-runtime-api-reference-op721.md	OP721 API
docs/contracts-btc-runtime-api-reference-safe-math.md	SafeMath API
docs/contracts-btc-runtime-contracts-op-net-base.md	OP_NET base class
docs/contracts-btc-runtime-contracts-op20-token.md	OP20 implementation
docs/contracts-btc-runtime-contracts-op20s-signatures.md	OP20S signatures
docs/contracts-btc-runtime-contracts-op721-nft.md	OP721 implementation
docs/contracts-btc-runtime-contracts-reentrancy-guard.md	Reentrancy guard
docs/contracts-btc-runtime-contracts-upgradeable.md	Upgradeable contracts
docs/contracts-btc-runtime-storage-stored-primitives.md	Stored primitives
docs/contracts-btc-runtime-storage-stored-maps.md	Stored maps
docs/contracts-btc-runtime-storage-stored-arrays.md	Stored arrays
docs/contracts-btc-runtime-storage-memory-maps.md	Memory maps
docs/contracts-btc-runtime-types-address.md	Address type
docs/contracts-btc-runtime-types-calldata.md	Calldata type
docs/contracts-btc-runtime-types-bytes-writer-reader.md	BytesWriter/Reader
docs/contracts-btc-runtime-types-safe-math.md	SafeMath type
docs/contracts-btc-runtime-advanced-cross-contract-calls.md	Cross-contract calls
docs/contracts-btc-runtime-advanced-signature-verification.md	Signature verification
docs/contracts-btc-runtime-advanced-quantum-resistance.md	Quantum resistance
docs/contracts-btc-runtime-advanced-bitcoin-scripts.md	Bitcoin scripts
docs/contracts-btc-runtime-advanced-contract-upgrades.md	Contract upgrades
docs/contracts-btc-runtime-advanced-plugins.md	Contract plugins
docs/contracts-btc-runtime-examples-basic-token.md	Basic token example
docs/contracts-btc-runtime-examples-stablecoin.md	Stablecoin example
docs/contracts-btc-runtime-examples-nft-with-reservations.md	NFT example
docs/contracts-btc-runtime-examples-oracle-integration.md	Oracle example

Other Contract Docs

File	Description
docs/contracts-as-bignum-README.md	BigNum library (u256, u128)
docs/contracts-opnet-transform-README.md	Transform decorators
docs/contracts-opnet-transform-std-README.md	Standard library
docs/contracts-example-tokens-README.md	Example tokens
docs/contracts-example-tokens-docs-OP_20.md	OP20 example

Client Libraries

File	Description
docs/clients-bitcoin-README.md	Bitcoin library overview
docs/clients-bitcoin-psbt.md	PSBT class, signing, finalization
docs/clients-bitcoin-payments.md	Payment types (P2TR, P2WPKH, P2WSH, P2SH, P2OP)
docs/clients-bitcoin-script.md	Script building, opcodes
docs/clients-bitcoin-address.md	Address encoding/decoding
docs/clients-bitcoin-transaction.md	Transaction class
docs/clients-bip32-README.md	BIP32 HD derivation
docs/clients-bip32-QUANTUM.md	Quantum support
docs/clients-ecpair-README.md	EC key pairs
docs/clients-walletconnect-README.md	WalletConnect
docs/clients-walletconnect-wallet-integration.md	Wallet integration

Testing

File	Description
docs/testing-unit-test-framework-README.md	Test framework
docs/testing-opnet-unit-test-README.md	Unit testing
docs/testing-opnet-unit-test-docs-README.md	Test docs
docs/testing-opnet-unit-test-docs-Blockchain.md	Blockchain mocking
docs/testing-opnet-unit-test-docs-ContractRuntime.md	Contract runtime

Frontend

File	Description
docs/frontend-motoswap-ui-README.md	Frontend guide (THE STANDARD)

Plugins

File	Description
docs/plugins-plugin-sdk-README.md	Plugin SDK
docs/plugins-opnet-node-README.md	OPNet node
docs/plugins-opnet-node-docker-README.md	Docker setup

Templates

Contract Templates (templates/contracts/)

File	Description
templates/contracts/OP20Token.ts	OP20 token implementation
templates/contracts/OP721NFT.ts	OP721 NFT implementation
templates/contracts/MyContract.ts	Generic contract template
templates/contracts/index.ts	Entry point / exports

Frontend Templates (templates/frontend/)

File	Description
templates/frontend/App.tsx	Main app component
templates/frontend/OPNetProvider.tsx	OPNet context provider
templates/frontend/WalletConnect.tsx	Wallet connection component
templates/frontend/ContractInteraction.tsx	Contract interaction component
templates/frontend/useWallet.ts	Wallet hook
templates/frontend/useContract.ts	Contract hook
templates/frontend/vite.config.ts	Vite configuration
templates/frontend/package.json	Package dependencies

Plugin Templates (templates/plugins/)

File	Description
templates/plugins/MyPlugin.ts	Generic plugin template
templates/plugins/OP20Indexer.ts	OP20 indexer plugin
templates/plugins/types.ts	Type definitions
templates/plugins/index.ts	Entry point
templates/plugins/plugin.json	Plugin manifest

Test Templates (templates/tests/)

File	Description
templates/tests/OP20.test.ts	OP20 test example
templates/tests/setup.ts	Test setup
templates/tests/gulpfile.js	Gulp build config

---

Advanced Transaction Features

When users ask about adding fees, notes, or advanced features to transactions (deployments, interactions, funding), ALWAYS check docs/core-transaction-transaction-factory-interfaces.md.

Common User Requests → Parameters

User Request	Parameter	Interface
“Add a fee” / “Set fee rate”	feeRate: number (sat/vB)	TransactionParameters
“Add priority fee”	priorityFee: bigint	TransactionParameters
“Add a note/memo”	note: string | Uint8Array	TransactionParameters
“Use anchor outputs”	anchor: true	TransactionParameters
“Send to multiple addresses”	extraOutputs: PsbtOutputExtended[]	TransactionParameters
“Send max/entire balance”	autoAdjustAmount: true	IFundingTransactionParameters
“Pay fees from separate UTXOs”	feeUtxos: UTXO[]	IFundingTransactionParameters
“Set minimum gas”	minGas: bigint	TransactionParameters
“Offline signing”	toOfflineBuffer() / fromOfflineBuffer()	CallResult methods
“Sign without broadcasting”	signTransaction()	CallResult method
“Broadcast pre-signed TX”	sendPresignedTransaction()	CallResult method

CallResult Transaction Methods

// Sign without broadcast
const signedTx = await simulation.signTransaction(params);

// Sign and broadcast
const receipt = await simulation.sendTransaction(params);

// Broadcast pre-signed
const receipt = await simulation.sendPresignedTransaction(signedTx);

// Offline signing workflow
const buffer = await simulation.toOfflineBuffer(address, amount);
const reconstructed = CallResult.fromOfflineBuffer(buffer);

Quick Example: Adding Fee + Note

await simulation.sendTransaction({
    signer: wallet.keypair,
    mldsaSigner: wallet.mldsaKeypair,
    refundTo: wallet.p2tr,
    network: networks.regtest,
    maximumAllowedSatToSpend: 100000n,
    feeRate: 15,                    // 15 sat/vB
    priorityFee: 5000n,             // +5000 sats priority
    note: "Payment for invoice #123", // OP_RETURN memo
});

For full details, read docs/core-transaction-transaction-factory-interfaces.md.

---

Contract Development

Key Concepts

1. Contracts use a custom AssemblyScript fork (@btc-vision/assemblyscript) – This fork adds closure support to standard AssemblyScript, enabling callbacks and higher-order function patterns. Always install @btc-vision/assemblyscript instead of the upstream assemblyscript package.
2. Constructor runs on EVERY interaction – Use onDeployment() for initialization
3. Contracts CANNOT hold BTC – They are calculators, not custodians
4. Verify-don’t-custody pattern – Check Blockchain.tx.outputs against internal state

Decorator Reference

// Mark method as callable
@method({ name: 'param1', type: ABIDataTypes.UINT256 })

// Specify return types
@returns({ name: 'result', type: ABIDataTypes.UINT256 })

// Declare emitted events
@emit('Transfer', 'Approval')

Storage Types

Type	Use Case
StoredU256	Single u256 value
StoredBoolean	Boolean flag
StoredString	String value
StoredMapU256	Key-value map (u256 keys/values)
AddressMemoryMap	In-memory address map

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Testing

ALL CODE MUST HAVE TESTS

import { opnet, OPNetUnit, Assert, Blockchain } from '@btc-vision/unit-test-framework';

await opnet('My Tests', async (vm: OPNetUnit) => {
    vm.beforeEach(async () => {
        Blockchain.dispose();
        await Blockchain.init();
    });

    await vm.it('should work correctly', async () => {
        const result = await contract.someMethod();
        Assert.expect(result).toEqual(expected);
    });
});

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Plugin Development

OPNet nodes are like Minecraft servers – they support plugins!

Key Resources

• Read docs/plugins-plugin-sdk-README.md
• Read docs/core-OIP-OIP-0003.md for plugin specification
• Use templates/plugins/OP20Indexer.ts for indexers

Plugin Lifecycle

Hook	When Called	Blocking
onFirstInstall	First installation	Yes
onNetworkInit	Every load	Yes
onBlockChange	New block confirmed	No
onReorg	Chain reorganization	Yes (CRITICAL)

Critical: Reorg Handling

You MUST implement onReorg() to revert state for reorged blocks. Failure to do so will cause data inconsistency.

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Frontend Development

Configuration Standard

Frontend configs MUST use docs/eslint-react.json and docs/tsconfig-generic.json:

• Vite + React
• Vitest for testing
• ESLint with TypeScript strict mode
• ESNext target

Caching (MANDATORY)

• Reuse provider instances – Singleton per network
• Reuse contract instances – Cache by address
• Cache API responses – Invalidate on block change

Key Hooks

// OPNet provider
const { provider, isConnected, network } = useOPNet();

// Contract interaction
const { contract, callMethod, loading } = useContract(address, abi);

// Wallet connection
const { address, connect, disconnect, signPsbt } = useWallet();

See docs/frontend-motoswap-ui-README.md for complete integration guide.

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Backend/API Development

MANDATORY Frameworks

Package	Purpose
@btc-vision/hyper-express	HTTP server (fastest)
@btc-vision/uwebsocket.js	WebSocket server (fastest)

FORBIDDEN: Express, Fastify, Koa, Hapi – they are significantly slower.

See docs/core-opnet-backend-api.md for complete guide.

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Official Wallet: OP_WALLET

OP_WALLET is the main and official wallet supporting OPNet. It is developed by the OPNet team and provides the most complete feature set for interacting with the OPNet Bitcoin L1 smart contract ecosystem.

Why OP_WALLET is Required for Full OPNet Support

Feature	OP_WALLET	Other Wallets
Official Support	Yes	No
MLDSA Signatures	Yes	No
Quantum-Resistant Keys	Yes	No
Full OPNet Integration	Yes	Partial
First-Party Updates	Yes	No

Key Capabilities

1. MLDSA (ML-DSA) Signatures: Only OP_WALLET supports quantum-resistant ML-DSA signatures, which are critical for future-proof security on OPNet
2. Full Address System Support: OP_WALLET properly handles both Bitcoin addresses (tweaked public keys) and OPNet addresses (ML-DSA public key hashes)
3. Native OPNet Features: Direct access to all OPNet features as they are released
4. Optimized UX: Built specifically for OPNet dApp interactions

Integration via WalletConnect

Use @btc-vision/walletconnect to integrate OP_WALLET into your dApp:

import { WalletConnectProvider, useWalletConnect, SupportedWallets } from '@btc-vision/walletconnect';

// Wrap your app
<WalletConnectProvider theme="dark">
  <App />
</WalletConnectProvider>

// In your component
const { connectToWallet, mldsaPublicKey, signMLDSAMessage } = useWalletConnect();

// Connect specifically to OP_WALLET for full feature support
connectToWallet(SupportedWallets.OP_WALLET);

// Use MLDSA signatures (OP_WALLET only)
if (mldsaPublicKey) {
  const signature = await signMLDSAMessage('Your message');
}

Installation

Install OP_WALLET from the Chrome Web Store

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Client Libraries

Package	Doc	Description
@btc-vision/bitcoin	docs/clients-bitcoin-README.md	Bitcoin lib (709x faster PSBT)
@btc-vision/bip32	docs/clients-bip32-README.md	HD derivation + quantum
@btc-vision/ecpair	docs/clients-ecpair-README.md	EC key pairs
@btc-vision/transaction	docs/core-transaction-README.md	OPNet transactions
opnet	docs/core-opnet-README.md	Main client library
@btc-vision/walletconnect	docs/clients-walletconnect-README.md	Wallet connection (OP_WALLET + UniSat)

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Version Requirements

Tool	Minimum Version
Node.js	>= 24.0.0
TypeScript	>= 5.9.3
AssemblyScript	@btc-vision/assemblyscript (custom fork with closure support)

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Critical Reminders

1. READ typescript-law FIRST – Non-negotiable rules
2. Verify project configuration – Before writing any code
3. NO any type – Ever
4. Test everything – Unit tests required
5. **Handle