BananaCrystal: FX rates, swaps and payments in 140+ currencies

com.bananacrystalPublished by bananacrystal.comOfficial publisherv1.1.0Updated Nov 7, 2026

Give your AI agent a wallet: live FX rates, swaps and payments in 140+ local currencies.

VerifiedStreamable HTTPWeb executableFinanceBusiness & Commerce

Overview

AI-generated overview

Hosted MCP wallet for AI agents: live FX rates, swaps, transfers and fiat on/off-ramp across 140+ local-currency stablecoins.

What you can do
  • Check balances, exchange rates, transaction history, limits and swap fee estimates
  • Swap between 140+ local-currency stablecoins
  • Send transfers to other users, with an email one-time code
  • Start KYC, deposits and withdrawals between fiat and stablecoins
  • Create, update, engage and cancel offers and trades
  • Request and execute approved agent-to-agent transactions
When to use it
Useful when an assistant should actually move or convert money rather than just report on it: paying an invoice in another currency, checking balances and rates, or letting an agent transact within caps you set. Start with a sandbox key to try the flows without real funds.
Requirements
Remote Streamable HTTP endpoint; nothing to install locally. A BananaCrystal account and either an API key sent in the x-api-key header or OAuth 2.0 sign-in with the key left empty. Sandbox keys start with bc_test_; production keys are 64 hex characters. KYC is required before fiat tools in production.
Before you install
This server can move real money. Transfers cost 0.3% and swaps 0.5%; fiat flows use a partner rate. Use scoped keys (read, transfer, swap, fiat), set per-transaction and 24-hour caps, and keep the email one-time code for transfers, swaps and withdrawals enabled. Treat the API key as a secret; a read-only key cannot move funds.

Installation

In SourceWeft

  1. Open BananaCrystal: FX rates, swaps and payments in 140+ currencies in the dashboard and add it to a workspace.
  2. Connect the required credentials. They are stored privately and never shown on public pages.
  3. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.bananacrystal%2Fmcp/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config. The client completes OAuth sign-in on first connect.

{
  "mcpServers": {
    "bananacrystal-fx-rates-swaps-and-payment": {
      "type": "http",
      "url": "https://agentic.bananacrystal.com/mcp"
    }
  }
}

README

BananaCrystal MCP Server

Give your AI agent a wallet: live FX rates, swaps and payments in 140+ local currencies.

One hosted MCP endpoint. 40 tools. Free sandbox. Settles on Hedera in under 5 seconds.

https://agentic.bananacrystal.com/mcp

Docs · Get a free sandbox key · API reference · Security policy

What this is

BananaCrystal is a hosted MCP server that gives an AI agent a wallet it can actually spend from. The agent can check balances, get a live exchange rate, swap between 140+ local-currency stablecoins, send money to another user, and move funds in and out of fiat, all through standard MCP tool calls. Limits are enforced on our side, so the agent never holds a private key and can never spend past the cap you set.

This repository holds the configuration files for connecting an MCP client to the hosted server. There is nothing to install or run locally. The server itself is hosted and maintained by BananaCrystal.

Connect in five minutes

  1. Create a free account at agents.bananacrystal.com/account and copy a sandbox key. Sandbox keys start with bc_test_ and come with test balances, so nothing real moves.
  2. Add the server to your MCP client.
  3. Ask your agent: "What is my USDb balance?"

Claude Desktop, Claude Code, Cursor, Windsurf, VS Code

Add this to your client's MCP config (claude_desktop_config.json, ~/.cursor/mcp.json, .vscode/mcp.json, or the equivalent):

json
{  "mcpServers": {    "bananacrystal": {      "url": "https://agentic.bananacrystal.com/mcp",      "headers": {        "x-api-key": "bc_test_your_key"      }    }  }}

Clients that do not yet accept a url entry directly (older Claude Desktop builds) can use mcp-remote:

json
{  "mcpServers": {    "bananacrystal": {      "command": "npx",      "args": [        "-y", "mcp-remote",        "https://agentic.bananacrystal.com/mcp",        "--header", "x-api-key:${BANANACRYSTAL_API_KEY}"      ],      "env": { "BANANACRYSTAL_API_KEY": "bc_test_your_key" }    }  }}

Claude Code (one line)

bash
claude mcp add --transport http bananacrystal https://agentic.bananacrystal.com/mcp --header "x-api-key: bc_test_your_key"

Gemini CLI

bash
gemini extensions install https://github.com/BananaCrystal/mcp-server-bananacrystalexport BANANACRYSTAL_API_KEY=bc_test_your_key

ChatGPT, Claude.ai connectors, and OAuth clients

Add https://agentic.bananacrystal.com/mcp as a custom connector or remote MCP server. Leave the API key empty and the client will walk you through OAuth 2.0 sign-in. The server advertises its authorization server at /.well-known/oauth-protected-resource.

Any language, no SDK

The server speaks Streamable HTTP, so any MCP client library works. The only thing you need is the URL and a key.

bash
curl -s https://agentic.bananacrystal.com/mcp \  -H "content-type: application/json" \  -H "x-api-key: bc_test_your_key" \  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

What your agent can do

GroupToolsFee
Read-onlyget_balances, get_exchange_rate, get_transaction_history, get_my_limits, estimate_swap_fees and 19 moreFree
Transferrequest_transfer_otp, transfer_tokens0.3%
Swapswap_currency across 140+ local-currency stablecoins0.5%
Fiatinitiate_kyc, initiate_deposit, request_withdrawalPartner rate shown before you confirm
Offers and tradescreate_offer, update_offer, engage_offer, cancel_trade and 2 moreFree to list
Agent to agentrequest_agent_transaction, execute_approved_transaction and 1 more0.3%

The full list with input schemas is at agents.bananacrystal.com/docs/mcp. Every tool also returns its schema through tools/list.

Example: pay an invoice in rupiah

User:  Pay Putri's invoice: Rp 1,500,000 from my USD balance.
Agent: get_exchange_rate(USD, IDR)           -> 1 USD = 16,360 IDR       swap_currency(91.69 USDb -> IDRb)      -> 1,500,000 IDRb, fee 0.5%       request_transfer_otp()                 -> code sent to your email       [you enter the 6-digit code]       transfer_tokens(1,500,000 IDRb, @putri) -> settled in 3.4s
       Paid. Total cost $0.73. Receipt saved.

Guardrails

Everything that limits spending lives on the server, not in the agent's prompt.

  • Scoped API keys. Each key gets only the scopes it needs: read, transfer, swap, fiat. A read-only key cannot move money, whatever the prompt says.
  • Per-transaction maximum and rolling 24-hour cap, set per key in your account and enforced server-side. A runaway loop stops at the number you chose.
  • Email one-time code on transfers, swaps and withdrawals, on by default. The agent can request the code; only you can supply it.
  • Idempotent requests. Retrying a call never pays twice.
  • Sandbox is a separate environment. bc_test_ keys never touch real balances.

Pricing

Reads are free. Transfers cost 0.3% and swaps 0.5%, charged in the currency you send. There is no monthly fee, no minimum and no per-call charge. Fiat deposits and withdrawals carry the partner's rate, which the agent sees before it confirms.

Sandbox and production

SandboxProduction
Key formatbc_test_ prefix64 hex characters, no prefix
BalancesTest funds, reset on requestReal
KYCNot requiredRequired before fiat tools
Rate limitReturned by get_my_limitsReturned by get_my_limits

About BananaCrystal

BananaCrystal is a registered money services business in the United States (FinCEN) and Canada (FINTRAC). Stablecoins are issued on Hedera and each local-currency token is backed one to one by the deposits that minted it. Learn more at bananacrystal.com.

Support and security

License

The configuration files in this repository are released under the MIT License. Use of the hosted server is governed by the BananaCrystal Terms and Conditions.

Source: README.md at commit c7f5ceb

Tools

0
This server asks you to sign in, so SourceWeft could not read its tools without an account and has not indexed them. What a connected account sees can depend on that account and its permissions.

Version history

1
  1. v1.1.0LatestNov 7, 2026

Score

85% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts