mcp-server-justlend

A Model Context Protocol (MCP) server that enables AI agents to interact with the JustLend DAO lending protocol on TRON. Supply assets, borrow against collateral, manage positions, and analyze DeFi portfolios — all through a unified AI interface.

Beyond JustLend-specific operations, the server also exposes a full set of general-purpose TRON chain utilities — balance queries, block/transaction data, token metadata, TRX transfers, smart contract reads/writes, staking (Stake 2.0), multicall, and more.

Overview

JustLend DAO is the largest lending protocol on TRON, based on the Compound V2 architecture. This MCP server wraps the full protocol functionality into tools and guided prompts that local MCP clients such as Claude Desktop, Codex, Claude Code, and Cursor can use.

📌 Current Version: JustLend V1

This MCP server currently supports JustLend V1 protocol. All contract addresses, ABIs, calculation functions, and lending operations are for V1.

Key Capabilities

JustLend Protocol

• Market Data: Real-time APYs, TVL, utilization rates, prices for all markets
  • Smart fallback: contract queries first, API fallback for reliability
  • TTL caching (30–60s) to reduce RPC calls
• Account Data: Full position analysis via Multicall3 batch queries (~2.5s vs ~8s legacy)
  • Health factor, collateral, borrow positions
  • On-chain Oracle prices with API fallback
• Batch Wallet Balances: Query all TRC20 token balances in a single Multicall3 RPC call
• Mining Rewards: Advanced mining reward calculation (based on justlend-app logic)
  • Detailed breakdown by market and reward token (USDD, TRX, WBTC, etc.)
  • USD value calculation with live token prices
• Supply / Borrow / Repay / Withdraw: Full lending operations with pre-flight checks
• Collateral Management: Enter/exit markets, manage what counts as collateral
• Portfolio Analysis: AI-guided risk assessment, health factor monitoring, optimization
• JST Voting / Governance: View proposals, cast votes, deposit/withdraw JST for voting power, reclaim votes
• Energy Rental: Rent energy from JustLend, calculate rental prices, query rental orders, return/cancel rentals
• sTRX Staking: Stake TRX to receive sTRX, unstake sTRX, claim staking rewards, check withdrawal eligibility
  • Precision-safe BigInt/string math for TRX Sun conversion and 18-decimal sTRX balances/exchange-rate display

Browser Wallet Signing

• TronLink Integration: Connect TronLink (and other TIP-6963 browser wallets) via the tronlink-signer SDK
• Sign-only mode: Server builds transactions, browser only signs — private keys never leave the wallet
• Confirmable transaction summaries: Contract writes pass a deterministic summary (network, contract, function, args, callValue, feeLimit, simulation status) to the signer
• Dual wallet mode: Users choose between browser (recommended) or agent (encrypted local storage)

General TRON Chain

• Balances: TRX balance (with Sun/TRX conversion), TRC20/TRC1155 token balances
• Blocks: Latest block, block by number/hash, block number, chain ID
• Transactions: Fetch transaction details, receipts, wait for confirmation
• Contracts: Read/write any contract, fetch on-chain ABI, multicall (v2 & v3), deploy, estimate energy
• Token Metadata: TRC20 info (name/symbol/decimals/supply), TRC721 metadata, TRC1155 URI
• Transfers: Send TRX, transfer TRC20 tokens, approve spenders
  • Transfer/approval paths validate recipient, token, and spender TRON addresses before signing
• Staking (Stake 2.0): Freeze/unfreeze TRX for BANDWIDTH or ENERGY, withdraw expired unfreeze
• Address Utilities: Hex ↔ Base58 conversion, address validation, resolution
• Wallet: Sign messages, secure key management via agent-wallet or browser wallet

Supported Markets

The protocol currently exposes 17 active + 6 paused legacy = 23 markets. Call get_supported_markets for the live list with addresses; the active markets are:

jToken	Underlying	Description
jTRX	TRX	Native TRON token
jUSDT	USDT	Tether USD
jUSDD	USDD	Decentralized USD (USDD/TRX supply‑mining rewards)
jUSD1	USD1	World Liberty Financial USD
jTUSD	TUSD	TrueUSD
jwstUSDT	wstUSDT	Wrapped staked USDT (yields underlying staking APY)
jsTRX	sTRX	Staked TRX (yields underlying staking APY)
jBTC	BTC	Bitcoin (wrapped)
jWBTC	WBTC	Wrapped Bitcoin
jETH	ETH	Ethereum — dApp UI displays as "ETH" (formerly "ETHOLD")
jETHB	ETHB	Bridged Ethereum — dApp UI displays as "ETHB" (formerly "ETH")
jSUN	SUN	SUN token
jJST	JST	JUST governance token
jWIN	WIN	WINkLink
jBTT	BTT	BitTorrent token
jNFT	NFT	APENFT
jHTX	HTX	HTX token

Paused / legacy markets (closed to new supply/borrow, queryable for read & to unwind positions): jUSDCOLD, jUSDD_OLD, jBUSDOLD, jSUNOLD, jUSDJ, jWBTT.

Prerequisites

• Node.js 20.0.0 or higher
• Optional: TronGrid API key for reliable mainnet access (strongly recommended)

Installation

git clone https://github.com/justlend/mcp-server-justlend.git
cd mcp-server-justlend
npm install

Quick Setup

For a guided setup experience (build, configure, generate .mcp.json, print Codex setup command):

bash scripts/setup-mcp-test.sh
# Add --claude-desktop to also print Claude Desktop JSON

The script checks Node.js 20+, installs dependencies, builds the project, generates local Claude Code config, and prints the local Codex registration command.

Configuration

Wallet Setup (First-Use Choice)

On first use, the server does not force a wallet choice. Users can explicitly choose between:

1. browser mode via TronLink using connect_browser_wallet
2. agent mode via encrypted local wallet using set_wallet_mode with mode="agent"

Private keys are never stored in environment variables by default. If the user selects agent mode, the encrypted wallet is stored in ~/.agent-wallet/.

You can also manage wallets via CLI or MCP tools:

CLI (agent-wallet)

# Import an existing private key or mnemonic
npx agent-wallet add

# Generate a new wallet
npx agent-wallet generate

# List all wallets
npx agent-wallet list

# Switch active wallet
npx agent-wallet activate <wallet-id>

MCP Tools (runtime)

Tool	Description
get_wallet_address	Shows current address, or returns first-use wallet selection guidance
connect_browser_wallet	Connect TronLink / browser wallet for signing
set_wallet_mode	Switch between browser and agent signing
get_wallet_mode	Show current signing mode and addresses
list_wallets	List all wallets with IDs, types, addresses
set_active_wallet	Switch active wallet by ID

Importing an existing private key is intentionally not exposed as an MCP tool because MCP arguments can be logged by clients and transports. Use the CLI instead:

npx agent-wallet import

# (Optional) For automated/CI setups, set the wallet password
export AGENT_WALLET_PASSWORD="your_wallet_password"

# Strongly recommended — avoids TronGrid 429 rate limiting on mainnet
export TRONGRID_API_KEY="your_trongrid_api_key"

Client Configuration

Build the local server first:

npm run build

All local client examples below use the built stdio entrypoint:

node /absolute/path/to/mcp-server-justlend/build/index.js

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "justlend": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-server-justlend/build/index.js"],
      "env": {
        "TRONGRID_API_KEY": "SET_VIA_SYSTEM_ENV"
      }
    }
  }
}

Codex

Recommended: register the local stdio server with codex mcp add:

codex mcp add justlend --env TRONGRID_API_KEY=your_trongrid_api_key -- \
  node /absolute/path/to/mcp-server-justlend/build/index.js

If you do not want to set a TronGrid key yet, omit the --env flag:

codex mcp add justlend -- node /absolute/path/to/mcp-server-justlend/build/index.js

Useful maintenance commands:

codex mcp list
codex mcp get justlend
codex mcp remove justlend

Claude Code

Add to .mcp.json in the project root:

{
  "mcpServers": {
    "justlend": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-server-justlend/build/index.js"],
      "env": {
        "TRONGRID_API_KEY": "SET_VIA_SYSTEM_ENV"
      }
    }
  }
}

Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "justlend": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-server-justlend/build/index.js"],
      "env": {
        "TRONGRID_API_KEY": "SET_VIA_SYSTEM_ENV"
      }
    }
  }
}

Usage

The server supports two transport modes. Both share the same Tools, Resources, and wallet initialization — the difference is how clients connect.

Stdio Mode (Local AI Clients)

npm start

The server communicates via stdin/stdout. This is the standard mode for local MCP clients like Claude Desktop, Codex, Claude Code, and Cursor, which launch the server as a child process.

HTTP/SSE Mode (Remote / Multi-Client)

MCP_API_KEY=my-secret-key npm run start:http

The server starts an Express HTTP service with Server-Sent Events (SSE) transport. Suitable for web applications, remote clients, or scenarios where multiple clients need to connect concurrently.

HTTP mode is fail-closed: MCP_API_KEY is required, the server binds to 127.0.0.1 by default, and CORS is disabled unless you explicitly set MCP_CORS_ORIGIN.

Endpoint	Method	Description
/sse	GET	SSE connection endpoint — returns a sessionId
/messages?sessionId=xxx	POST	Send MCP messages for a session
/health	GET	Health check (no auth required)

Environment variables:

Variable	Default	Description
PORT	3001	HTTP listen port
MCP_HOST	127.0.0.1	HTTP listen host. Keep the default unless you intentionally want remote exposure.
MCP_API_KEY	(required)	Bearer token for authentication. HTTP mode refuses to start without it.
MCP_CORS_ORIGIN	(disabled)	Allowed CORS origin. If unset, no CORS headers are sent.
MCP_MAX_SESSIONS	100	Maximum concurrent SSE sessions
MCP_SESSION_TIMEOUT_MS	1800000	Session idle timeout in ms (default: 30 min)

Example with authentication:

MCP_API_KEY=my-secret-key PORT=8080 npm run start:http

# Connect from client
curl -H "Authorization: Bearer my-secret-key" http://localhost:8080/sse

Development

npm run dev          # Stdio with auto-reload
npm run dev:http     # HTTP/SSE with auto-reload

API Reference

Tools (59 total)

Wallet & Network

Tool	Description	Write?
get_wallet_address	Show wallet address or first-use wallet selection guidance	No
connect_browser_wallet	Connect TronLink / browser wallet for signing	Yes
set_wallet_mode	Switch between browser and agent signing	Yes
get_wallet_mode	Show current signing mode and addresses	No
list_wallets	List all wallets (IDs, types, addresses)	No
set_active_wallet	Switch active wallet by wallet ID	No
get_supported_networks	List available networks	No
get_supported_markets	List all jToken markets with addresses	No
set_network	Set global default network (mainnet, nile)	Yes
get_network	Get current global default network	No

Market Data

Tool	Description	Write?
get_market_data	Detailed data for one market (APY, TVL, rates) — contract + API fallback	No
get_all_markets	Overview of all markets — contract + API fallback	No
get_protocol_summary	Comptroller config & protocol parameters — contract query	No

Account & Balances

Tool	Description	Write?
get_account_summary	Full position: supplies, borrows, health factor — Multicall3 batch	No
check_allowance	Check TRC20 approval for jToken	No
get_trx_balance	TRX balance	No
get_token_balance	TRC20 token balance	No
get_wallet_balances	Batch-fetch TRC20 balances across multiple markets via Multicall3	No

Lending Operations

Tool	Description	Write?
supply	Deposit assets to earn interest	Yes
withdraw	Withdraw supplied assets	Yes
withdraw_all	Withdraw all from a market	Yes
borrow	Borrow against collateral	Yes
repay	Repay outstanding borrows	Yes
enter_market	Enable market as collateral	Yes
exit_market	Disable market as collateral	Yes
approve_underlying	Approve TRC20 for jToken	Yes
claim_rewards	Claim mining rewards	Yes
estimate_lending_energy	Estimate energy/bandwidth/TRX cost for any lending operation	No

Mining & Rewards

Tool	Description	Write?
get_mining_rewards	Unclaimed mining rewards, APY, and reward breakdown	No
get_usdd_mining_config	USDD mining periods, reward tokens, and schedule	No
get_wbtc_mining_config	WBTC supply mining configuration and activity details	No

JST Voting / Governance

Tool	Description	Write?
get_proposal_list	List all governance proposals with status and vote counts	No
get_user_vote_status	User's voting history: voted proposals, withdrawable votes	No
get_vote_info	Voting power: JST balance, available votes, locked votes	No
get_locked_votes	Votes locked in a specific proposal	No
check_jst_allowance_for_voting	Check JST approval for WJST voting contract	No
approve_jst_for_voting	Approve JST for the WJST voting contract	Yes
deposit_jst_for_votes	Deposit JST to get voting power (1 JST = 1 Vote)	Yes
withdraw_votes_to_jst	Withdraw WJST back to JST	Yes
cast_vote	Cast for/against votes on a proposal	Yes
withdraw_votes_from_proposal	Reclaim votes from completed proposals	Yes

Energy Rental

Tool	Description	Write?
get_energy_rental_dashboard	Market data: TRX price, exchange rate, APY, energy per TRX	No
get_energy_rental_params	On-chain params: fees, limits, pause status, usage charge ratio	No
calculate_energy_rental_price	Estimate cost for renting energy (prepayment, deposit, daily cost)	No
get_energy_rental_rate	Current rental rate for a given TRX amount	No
get_user_energy_rental_orders	User's rental orders (as renter, receiver, or all)	No
get_energy_rent_info	On-chain rental info for a renter-receiver pair	No
get_return_rental_info	Return/cancel estimation (refund, remaining rent, daily cost)	No
rent_energy	Rent energy for a receiver (with balance, pause, limit checks)	Yes
return_energy_rental	Cancel an active rental (with active order check)	Yes

sTRX Staking

Tool	Description	Write?
get_strx_dashboard	Staking market data: exchange rate, APY, total supply	No
get_strx_account	User staking account: staked amount, income, rewards	No
get_strx_balance	sTRX token balance for an address	No
check_strx_withdrawal_eligibility	Check unbonding status, pending/completed withdrawal rounds	No
stake_trx_to_strx	Stake TRX to receive sTRX with precision-safe string amount parsing (with balance check)	Yes
unstake_strx	Unstake sTRX to receive TRX back (with balance check)	Yes
claim_strx_rewards	Claim all staking rewards (with rewards existence check)	Yes

Transfers

Tool	Description	Write?
transfer_trx	Transfer TRX to another address (with balance check)	Yes
transfer_trc20	Transfer TRC20 tokens by symbol or contract address; validates token and recipient addresses before signing	Yes

Prompts (AI-Guided Workflows)

Prompt	Description
getting_started	First-time onboarding: wallet setup, connection, feature tour
supply_assets	Step-by-step supply with balance checks and approval
borrow_assets	Safe borrowing with risk assessment and health factor checks
repay_borrow	Guided repayment with verification
analyze_portfolio	Comprehensive portfolio analysis with risk scoring
compare_markets	Find best supply/borrow opportunities
rent_energy	Guided energy rental with price estimation and balance checks
stake_trx	Guided TRX staking to sTRX with APY info and verification
query_proposals	Browse and query governance proposals, check voting requirements
cast_vote	Guided governance voting with vote verification

Architecture

mcp-server-justlend/
├── src/
│   ├── core/
│   │   ├── chains.ts          # Network configs + JustLend contract addresses
│   │   ├── abis.ts            # jToken, Comptroller, Oracle, TRC20 ABIs
│   │   ├── tools/             # MCP tool registrations (59 tools)
│   │   │   ├── index.ts           # Barrel export
│   │   │   ├── wallet-tools.ts    # Wallet, network, transfer tools
│   │   │   ├── market-tools.ts    # Market data, balance, mining tools
│   │   │   ├── lending-tools.ts   # Supply, borrow, repay, collateral tools
│   │   │   ├── voting-tools.ts    # Governance proposal & voting tools
│   │   │   ├── energy-tools.ts    # Energy rental tools
│   │   │   ├── staking-tools.ts   # sTRX staking tools
│   │   │   └── shared.ts         # Shared helpers
│   │   ├── prompts.ts         # AI-guided workflow prompts
│   │   ├── resources.ts       # Static protocol info resource
│   │   ├── browser-signer.ts  # tronlink-signer SDK adapter (TronWalletSigner wrapper)
│   │   └── services/
│   │       ├── # — JustLend-specific —
│   │       ├── global.ts     # Global state: network, wallet mode
│   │       ├── clients.ts    # TronWeb client factory (cached)
│   │       ├── wallet.ts     # Wallet routing: browser / agent-wallet signing
│   │       ├── cache.ts      # TTL cache layer (30–60s) for prices, markets, sTRX
│   │       ├── price.ts      # On-chain Oracle prices with API fallback
│   │       ├── markets.ts    # APY, TVL, utilization — contract + API fallback
│   │       ├── account.ts    # User positions via Multicall3 batch queries
│   │       ├── lending.ts    # supply, borrow, repay, withdraw, collateral
│   │       ├── rewards.ts    # Mining reward calculation (USDD, TRX, WBTC)
│   │       ├── voting.ts     # JST governance: proposals, cast vote, deposit/withdraw WJST
│   │       ├── energy-rental.ts # Energy rental: query, calculate, rent, return
│   │       ├── strx-staking.ts  # sTRX staking: stake, unstake, rewards, withdrawal check
│   │       ├── # — General TRON chain —
│   │       ├── address.ts     # Hex ↔ Base58 conversion, validation
│   │       ├── balance.ts     # TRX balance (rich), TRC20/TRC1155 balances
│   │       ├── blocks.ts      # Block queries, block number, chain ID
│   │       ├── transactions.ts# getTransaction, getTransactionInfo, waitForTransaction
│   │       ├── transfer.ts    # transferTRX, transferTRC20, approveTRC20
│   │       ├── tokens.ts      # TRC20/TRC721/TRC1155 metadata
│   │       ├── contracts.ts   # readContract, writeContract, multicall, deploy, estimateEnergy
│   │       ├── multicall-abi.ts # Multicall2 & Multicall3 ABIs
│   │       ├── staking.ts     # Stake 2.0: freeze, unfreeze, withdrawExpireUnfreeze
│   │       └── utils.ts       # toSun/fromSun, formatJson, hexToNumber, isAddress, …
│   ├── server/
│   │   ├── server.ts          # MCP server init
│   │   └── http-server.ts     # Express HTTP/SSE transport
│   └── index.ts               # Stdio entry point
├── bin/cli.js                 # CLI entry for npx
├── scripts/
│   └── setup-mcp-test.sh      # Quick setup: build + generate .mcp.json config
└── tests/
    └── core/
        ├── chains.test.ts
        └── services/
            ├── services.test.ts        # Client cache, legacy balance tests
            ├── address.test.ts         # Pure: address format conversion (16 tests)
            ├── utils.test.ts           # Pure: unit conversions, formatters (26 tests)
            ├── cache.test.ts           # Unit: TTL cache behavior
            ├── price.test.ts           # Unit: price service fallback logic
            ├── markets-fallback.test.ts # Unit: market data fallback chain
            ├── strx-fallback.test.ts   # Unit: sTRX dashboard fallback
            ├── account-multicall.test.ts # Unit: Multicall3 account queries
            ├── balance.test.ts         # Integration: TRX & TRC20 balances
            ├── blocks.test.ts          # Integration: block queries
            ├── contracts.test.ts       # Mixed: pure ABI helpers + integration reads
            ├── tokens.test.ts          # Integration: TRC20 token metadata
            ├── transactions.test.ts    # Integration: transaction fetch
            ├── transfer.test.ts        # Write: skipped by default (TEST_TRANSFER=1)
            ├── staking.test.ts         # Write: skipped by default (TEST_STAKING=1)
            ├── energy-rental.test.ts   # Integration: energy rental queries; Write: skipped (TEST_ENERGY_RENTAL=1)
            ├── strx-staking.test.ts    # Integration: sTRX queries; Write: skipped (TEST_STRX_STAKING=1)
            └── wallet.test.ts          # Unit: agent-wallet integration tests

Testing

# Run all tests (pure/unit tests always pass; integration tests need network)
npm test

# Run individual test files (recommended to avoid TronGrid rate limits)
npx vitest run tests/core/services/utils.test.ts
npx vitest run tests/core/services/address.test.ts
npx vitest run tests/core/services/balance.test.ts
npx vitest run tests/core/services/blocks.test.ts
npx vitest run tests/core/services/contracts.test.ts
npx vitest run tests/core/services/transactions.test.ts
npx vitest run tests/core/services/tokens.test.ts

# Energy rental & sTRX staking read tests
npx vitest run tests/core/services/energy-rental.test.ts
npx vitest run tests/core/services/strx-staking.test.ts

# Enable write/staking tests (uses real funds — use Nile testnet!)
# Requires agent-wallet to be configured: npx agent-wallet start
TEST_TRANSFER=1 npx vitest run tests/core/services/transfer.test.ts
TEST_STAKING=1 npx vitest run tests/core/services/staking.test.ts
TEST_ENERGY_RENTAL=1 npx vitest run tests/core/services/energy-rental.test.ts
TEST_STRX_STAKING=1 npx vitest run tests/core/services/strx-staking.test.ts

Rate limiting: Integration tests make real RPC calls to TronGrid. Without TRONGRID_API_KEY the free tier limits to a few requests per second. Run test files individually, or set TRONGRID_API_KEY to avoid 429 errors.

Security Considerations

• Private keys are managed by @bankofai/agent-wallet — never stored in environment variables or exposed via MCP tools
• Wallet encryption: Keys are stored in ~/.agent-wallet/ with password-based encryption
• Write operations are clearly marked with destructiveHint: true in MCP annotations
• Transaction summaries before signing: contract write paths pass signer-facing summaries with network, contract, function, arguments, callValue, feeLimit, and simulation status
• Address validation before signing: transfer and approval services reject invalid recipient/token/spender addresses before contract loading or wallet signing
• Precision-safe value handling: sTRX staking uses string/BigInt parsing for TRX Sun conversion and 18-decimal sTRX display/estimates
• Health factor checks in prompts prevent dangerous borrowing
• Always test on Nile testnet before mainnet operations
• Be cautious with unlimited approvals (approve_underlying with max)

Example Conversations

"What are the best supply rates on JustLend right now?" → AI calls get_all_markets, sorts by supplyAPY, presents ranking

"I want to supply 10,000 USDT to earn interest" → AI uses supply_assets prompt: checks balance → approves USDT → supplies → verifies

"Am I at risk of liquidation?" → AI calls get_account_summary, analyzes health factor, warns if < 1.5

"Borrow 500 USDT against my TRX collateral" → AI uses borrow_assets prompt: checks collateral → calculates new health factor → executes if safe

"What is the TRX balance of address TXxx...?" → AI calls the general-purpose TRX balance tool, returns balance in both TRX and Sun

"Freeze 100 TRX for ENERGY" → AI calls staking service to freeze via Stake 2.0, returns transaction hash

"Show me the latest governance proposals" → AI calls get_proposal_list, displays proposals sorted by ID with status and vote counts

"I want to vote for proposal #425 with 1000 JST" → AI checks get_vote_info → if no votes, suggests approve_jst_for_voting + deposit_jst_for_votes → then cast_vote

"Withdraw my votes from completed proposals" → AI calls get_user_vote_status to find withdrawable proposals → calls withdraw_votes_from_proposal for each

"How much does it cost to rent 300,000 energy for 7 days?" → AI calls calculate_energy_rental_price with energyAmount=300000, durationHours=168, returns cost breakdown

"Rent 500,000 energy to address TXxx... for 14 days" → AI uses rent_energy prompt: checks balance → checks rental status → calculates price → rents energy → verifies

"Cancel my energy rental to TXxx..." → AI calls get_energy_rent_info to verify active rental → calls return_energy_rental → confirms refund

"Stake 1000 TRX to earn sTRX rewards" → AI uses stake_trx prompt: checks balance → checks exchange rate & APY → stakes TRX → verifies sTRX received

"Do I have any sTRX rewards to claim?" → AI calls get_strx_account to check claimable rewards → calls claim_strx_rewards if available

"Can I withdraw my unstaked TRX?" → AI calls check_strx_withdrawal_eligibility to check unbonding status and completed withdrawal rounds

License

MIT License Copyright (c) 2026 JustLend