What is crossfin AGENTS.md?

A project instruction file describing CrossFin, a cross-border crypto routing engine for AI agents, its architecture, key files, and API address.

Understanding the CrossFin codebase, locating important files, and working with its API, exchange-routing logic, MCP server, web demo, and documentation.

It gives coding agents the project context they need before changing code, reducing guesswork about how the repository is organized and what its main components do.

How bubilife1202/crossfin configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to bubilife1202/crossfin. 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/bubilife1202/crossfin/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/bubilife1202/crossfin

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/bubilife1202/crossfin/agents-md/github.svg)](https://agentmods.dev/instructions/bubilife1202/crossfin/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/bubilife1202/crossfin/agents-md"><img src="https://agentmods.dev/badge/instructions/bubilife1202/crossfin/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/bubilife1202/crossfin/agents-md"><img src="https://agentmods.dev/badge/instructions/bubilife1202/crossfin/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,327 This file is loaded in full into every session.

When invoked 1,327 The same file — it is already loaded in full.

Security scan A 1 finding. 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	$0.01327	$0.01327
Opus 5.5	$0.00531	$0.00531
Sonnet 5.5	$0.00265	$0.00265
Haiku 4.5	$0.00133	$0.00133

Measured 2mo ago against content hash 84ee18a9af23, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

crossfin AGENTS.md scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl https://crossfin.dev/api/health

AGENTS.md · 145 lines

How it starts

The opening of the file, as written. The whole thing — 145 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md — CrossFin

What is CrossFin?

Cross-border crypto routing engine for AI agents. Routes capital across 14 Korean and global exchanges with x402 USDC micropayments on Base.

Architecture

apps/
  api/          Hono on Cloudflare Workers — main API (x402, registry, routing, market data)
  mcp-server/   MCP server (npm: crossfin-mcp) — 16 tools for Claude, Cursor, etc.
  web/          React demo — local ledger UI
  live/         Live demo site (live.crossfin.dev)
  docs/         VitePress documentation (docs.crossfin.dev)
  demo-video/   Remotion video generator

Key Files

apps/api/src/index.ts — All API routes (~11500 lines)
apps/api/src/constants.ts — Exchange fees, bridge coins, routing config
apps/api/src/types.ts — Type definitions and utility functions
apps/api/src/lib/fetchers.ts — Exchange data fetchers
apps/api/src/lib/engine.ts — Routing engine logic
apps/api/src/catalog.ts — Service catalog metadata (from catalog/crossfin-catalog.json)
apps/mcp-server/src/index.ts — MCP server with 16 tools
apps/mcp-server/src/ledgerStore.ts — Local JSON ledger for agent wallets

API Base URL

Production: https://crossfin.dev

Endpoints Overview

Free: health, exchange list, fees, pairs, status, arbitrage demo, routing graph, registry, ACP quote
Paid (x402 USDC on Base): route finding ($0.10), kimchi premium ($0.05), orderbooks ($0.02), Korean stocks ($0.03-$0.05), bundles ($0.10-$0.20)

Discovery Endpoints

/.well-known/crossfin.json — CrossFin agent discovery
/.well-known/x402.json — x402 payment discovery
/.well-known/agent.json — Google A2A Agent Card
/.well-known/ai-plugin.json — OpenAI plugin manifest
/llms.txt — LLM-readable site map
/api/openapi.json — OpenAPI 3.1 spec
/api/docs/guide — Structured agent onboarding guide

Exchanges

Korea: Bithumb, Upbit, Coinone, GoPax Regional: bitFlyer (JPY), WazirX (INR), bitbank (JPY), Indodax (IDR), Bitkub (THB) Global: Binance, OKX, Bybit, KuCoin, Coinbase Bridge coins: BTC, ETH, XRP, SOL, DOGE, ADA, DOT, LINK, AVAX, TRX, KAIA, SUI, APT

Read the full file on GitHub · 145 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 · 145 lines · 1,327 tokens per session scan A 84ee18a9af23

Subscribe to this mod's changes

crossfin AGENTS.md is an instructions file published in the GitHub repository bubilife1202/crossfin (1 stars, last pushed 5d ago), licensed MIT. It adds 1,327 tokens to every session, about $0.0053 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

ai-agents cloudflare-workers cryptocurrency defi kimchi-premium korea

crossfin AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
crossfin AGENTS.mdbubilife1202/crossfin	Instructions file	1	5d ago	MIT	A	1,327	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	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	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

crossfin: Instructions file for Codex