Bankr x402 SDK - Transaction Builder

Bankr x402 SDK - Transaction Builder is a skill for Claude Code from BankrBot/claude-plugins. It costs 106 tokens per session (840 once invoked), scanned A, original, MIT.

A transaction builder for common blockchain actions, such as sending tokens, managing NFTs, swapping assets, and moving tokens between networks. It turns plain-language requests into transaction types that an application can use.

In plain words
What is it for?
Use it to build transactions for ETH and token transfers, wrapping and unwrapping WETH, NFT purchases and mints, approvals, and cross-network transfers.
Why use it?
It avoids designing separate transaction-handling logic for each transfer, NFT operation, token conversion, bridge, or DeFi action.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the bankr-x402-sdk-dev plugin — 8 skills, 1 agent shipped together

Good fit Use it to build transactions for ETH and token transfers, wrapping and unwrapping WETH, NFT purchases and mints, approvals, and cross-network transfers.

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Install with agentmods
npx agentmods add skills/bankrbot/claude-plugins/sdk-transaction-builder
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.

Any agent
npx skills add BankrBot/claude-plugins --skill sdk-transaction-builder
Clone the repo
git clone --depth 1 https://github.com/BankrBot/claude-plugins

Made for: Claude Code.

Or install bankr-x402-sdk-dev, the plugin that ships this one along with the rest of its 8 skills, 1 agent.

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.

agentmods badge for Bankr x402 SDK - Transaction Builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/bankrbot/claude-plugins/sdk-transaction-builder.svg)](https://agentmods.dev/skills/bankrbot/claude-plugins/sdk-transaction-builder)
Your own site
<a href="https://agentmods.dev/skills/bankrbot/claude-plugins/sdk-transaction-builder"><img src="https://agentmods.dev/badge/skills/bankrbot/claude-plugins/sdk-transaction-builder.svg" alt="Measured on agentmods" height="20"></a>
Per session 106 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 840 The whole file, excluding the scripts and references it only reads on demand.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00106 $0.00840
Opus 5 $0.00053 $0.00420
Sonnet 5 $0.00021 $0.00168
Haiku 4.5 $0.00011 $0.00084

Measured 8d ago against content hash f45f4d88b1b0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

Bankr x402 SDK - Transaction Builder 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 8d 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.

x402-sdk-dev/skills/sdk-transaction-builder/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SDK Transaction Builder

Build blockchain transactions for transfers, NFTs, bridges, and DeFi operations.

Transaction Types

Type Description Example Prompt
transfer_erc20 Send ERC20 tokens "Send 100 USDC to 0x..."
transfer_eth Send native ETH "Send 0.1 ETH to 0x..."
convert_eth_to_weth Wrap ETH "Wrap 0.5 ETH"
convert_weth_to_eth Unwrap WETH "Unwrap 1 WETH"
transfer_nft Send NFT "Transfer my NFT #123 to 0x..."
buy_nft Purchase NFT "Buy the cheapest Pudgy Penguin"
mint_manifold_nft Mint from Manifold "Mint from Manifold at 0x..."
mint_seadrop_nft Mint from SeaDrop "Mint from SeaDrop at 0x..."
swapCrossChain Bridge tokens "Bridge 100 USDC from Ethereum to Base"

Prompt Patterns

# Transfers
"Send 100 USDC to 0x742d35..."
"Transfer 0.5 ETH to vitalik.eth"
"Send 50 USDC to 0x123... on Base"

# ETH/WETH
"Wrap 0.5 ETH to WETH"
"Unwrap 1 WETH to ETH"

# NFTs
"Transfer my Pudgy Penguin #1234 to 0x..."
"Buy the cheapest Pudgy Penguin on OpenSea"
"Mint NFT from Manifold contract 0x..."

# Cross-Chain
"Bridge 100 USDC from Ethereum to Base"
"Move 0.5 ETH from Base to Ethereum"

Usage

import { BankrClient } from "@bankr/sdk";

const client = new BankrClient({
  privateKey: process.env.BANKR_PRIVATE_KEY as `0x${string}`,
});

// Transfer tokens
const result = await client.promptAndWait({
  prompt: "Send 100 USDC to 0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0",
});

if (result.status === "completed" && result.transactions) {
  const tx = result.transactions[0].metadata.transaction;
  await wallet.sendTransaction(tx);
}

Transaction Metadata

All transactions include metadata for verification:

const tx = result.transactions[0];
const meta = tx.metadata.__ORIGINAL_TX_DATA__;

console.log(`Chain: ${meta.chain}`);
console.log(`Amount: ${meta.inputTokenAmount} ${meta.inputTokenTicker}`);
console.log(`To: ${meta.receiver}`);
console.log(`Message: ${meta.humanReadableMessage}`);

Read the full file on GitHub · 96 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.

  1. 8d ago First seen · 96 lines · 106 tokens per session scan A f45f4d88b1b0

Subscribe to this mod's changes

Bankr x402 SDK - Transaction Builder is a skill published in the GitHub repository BankrBot/claude-plugins (85 stars, last pushed 5mo ago), licensed MIT. It adds 106 tokens to every session and 840 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.