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, participate in V2 (Moolah) isolated markets and vaults, 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. 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: v1.1.0 — supports both JustLend V1 and JustLend V2 (Moolah)

• JustLend V1 (Compound V2 fork): the original pool-based protocol — jUSDT, jTRX, jUSDD, jSUN, jWBTC, etc. Full supply / borrow / repay / withdraw / collateral management and mining rewards.

• JustLend V2 (Moolah) (Morpho Blue fork): isolated markets with MarketParams (loanToken, collateralToken, oracle, irm, lltv) and ERC4626 vaults that auto-allocate across markets. Full vault deposit / redeem, collateral supply / borrow / repay / liquidate, and public liquidations.

Key Capabilities

JustLend V1 (pool-based, Compound V2 fork)

• 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

JustLend V2 — Moolah (New in v1.1.0)

• ERC4626 Vaults (TRX / USDT / USDD on mainnet; TRX + USDT on nile): auto-compounding yield with a curator that allocates deposits across isolated markets. Deposit / withdraw (by asset amount or max) / redeem (by shares) with TRC20 approvals handled as a separate tool so LLMs can reason about each step.

• Isolated Markets: each market is a (loanToken, collateralToken, oracle, irm, lltv) tuple. Supply collateral → borrow → repay → withdraw collateral, plus a composite moolah_borrow that handles collateral+borrow as two sequential txs. TRX routes through the TrxProviderProxy contract; TRC20 goes through MoolahProxy directly.

• Public Liquidations: list undercollateralized positions (risk > 1.0), quote loan-token requirement for a target seize, execute liquidation. Includes an explicit approve_liquidator_token step.

• Dashboard + History: aggregated user position, APY / TVL time-series for vaults and markets, paginated V2 transaction records.

• Gas estimation: estimate_moolah_energy returns typical historical energy / bandwidth / TRX cost for every V2 write op.

Historical records (New in v1.1.0)

• Paginated REST wrappers for V1 lending / sTRX / voting / energy-rental / liquidation history, plus V2 Moolah records. Each endpoint's numeric action/op codes are enriched with human-readable names (actionName / opName) client-side so MCP tools are self-describing.

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

Related MCP server: TRON Energy/Bandwidth MCP Server

Supported Markets

JustLend V1 (pool-based)

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:

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

JustLend V2 (Moolah) — vaults

Markets are not enumerated here because they are created dynamically on-chain; use get_moolah_markets to list them at runtime (each market returns a marketId / id plus loanSymbol / collateralSymbol / lltv / rates).

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)

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.

Environment variables:

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

Machine-readable tool catalog for AI agents: mcp-api-list.md — a complete, offline-loadable list of every tool with its input schema (parameter / type / required / default), MCP side-effect annotations (read-only vs. on-chain write / destructive) and HITL guidance. It is generated from source (npm run gen:api-list, see scripts/gen-mcp-api-list.ts) so it never drifts from the actual tool definitions. Agents can load it to plan tool routing without connecting to the server.

Tools (96 total)

Numbers by category: V1 base 59 · JustLend V2 (Moolah) 30 · historical records 7. See mcp-api-list.md (generated from source) for the authoritative per-tool catalog.

Wallet & Network

Market Data

Account & Balances

Lending Operations

Mining & Rewards

JST Voting / Governance

Energy Rental

sTRX Staking

Transfers

JustLend V2 (Moolah) — Vaults

JustLend V2 (Moolah) — Markets

JustLend V2 (Moolah) — Liquidation

JustLend V2 (Moolah) — Dashboard, History & Estimation

Historical Records (V1 + airdrop) — mainnet-only

Prompts (AI-Guided Workflows)

Architecture

mcp-server-justlend/
├── src/
│   ├── core/
│   │   ├── chains.ts          # Network configs + V1 jTokens + V2 Moolah addresses (mainnet + nile)
│   │   ├── abis.ts            # jToken, Comptroller, Oracle, TRC20 + 4 Moolah ABIs
│   │   ├── tools/             # MCP tool registrations (96 tools)
│   │   │   ├── index.ts                      # Barrel: registers all 10 tool modules
│   │   │   ├── wallet-tools.ts               # Wallet, network, transfer
│   │   │   ├── market-tools.ts               # V1 market data, balance, mining
│   │   │   ├── lending-tools.ts              # V1 supply / borrow / repay / collateral / approve / estimate
│   │   │   ├── voting-tools.ts               # V1 governance proposals & voting
│   │   │   ├── energy-tools.ts               # Energy rental
│   │   │   ├── staking-tools.ts              # sTRX staking
│   │   │   ├── moolah-vault-tools.ts         # V2 vault (6 tools)
│   │   │   ├── moolah-market-tools.ts        # V2 market (8 tools)
│   │   │   ├── moolah-liquidation-tools.ts   # V2 liquidation (5 tools)
│   │   │   ├── moolah-dashboard-tools.ts     # V2 dashboard + history + estimator (6 tools)
│   │   │   ├── records-tools.ts              # V1 + airdrop records (6 tools, mainnet-only)
│   │   │   └── shared.ts                     # Shared helpers
│   │   ├── prompts.ts         # AI-guided workflow prompts (14: 10 V1-era + 4 V2 Moolah)
│   │   ├── resources.ts       # Static protocol info resource
│   │   ├── browser-signer.ts  # tronlink-signer SDK adapter (TronWalletSigner wrapper)
│   │   └── services/
│   │       ├── # — Global + utilities —
│   │       ├── 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
│   │       ├── http.ts       # fetchWithTimeout
│   │       ├── utils.ts      # toSun/fromSun, formatJson, hexToNumber, isAddress, …
│   │       ├── bigint-math.ts# BigInt helpers: divRound, formatPercentRatio, USD cent math
│   │       ├── resource-prices.ts # Energy / bandwidth prices in sun
│   │       ├── # — JustLend V1 —
│   │       ├── 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    # V1 supply / borrow / repay / withdraw / collateral / estimator
│   │       ├── 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
│   │       ├── records.ts    # V1 + cross-cutting paginated REST history + airdrop scan
│   │       ├── # — JustLend V2 (Moolah) —
│   │       ├── moolah-backend.ts    # REST wrapper for zenvora.ablesdxd.link
│   │       ├── moolah-query.ts      # On-chain view reads (market state, vault totalAssets, health, etc.)
│   │       ├── moolah-vault.ts      # Vault write ops (deposit / withdraw / redeem / approve)
│   │       ├── moolah-market.ts     # Market write ops (supply collateral / borrow / repay / composite)
│   │       ├── moolah-liquidation.ts# liquidate + approveLiquidatorToken
│   │       ├── moolah-dashboard.ts  # Aggregated dashboard + history helpers
│   │       ├── moolah-estimate.ts   # Typical energy / bandwidth for all V2 write ops
│   │       ├── # — 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, estimateEnergy + callValueToSafeNumber
│   │       ├── multicall-abi.ts # Multicall2 & Multicall3 ABIs
│   │       └── staking.ts     # Stake 2.0: freeze, unfreeze, withdrawExpireUnfreeze
│   ├── server/
│   │   ├── server.ts          # MCP server init
│   │   ├── http-server.ts     # Express HTTP/SSE transport (uses auth.ts for Bearer check)
│   │   └── auth.ts            # Constant-time Bearer-token comparison (crypto.timingSafeEqual)
│   └── 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

# Moolah V2 end-to-end write-path test on nile (vault deposit/withdraw +
# market supply-collateral/borrow/repay). Requires a funded nile wallet:
# see forTest/docs/v1.1.0/nile-write-path-runbook.md for the runbook.
TEST_MOOLAH_WRITE=1 npx vitest run tests/integration/moolah-writes.nile.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.

Troubleshooting

For deeper inspection, run the server under the MCP Inspector and watch stderr — startup diagnostics, auth failures, and schema errors are logged there (stdout is reserved for the MCP protocol frames in stdio mode).

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

• Self-describing amounts: balance/amount fields return human-readable values with explicit _unit + decimals (and raw where applicable) so agents never re-apply decimals or misjudge magnitude. New tools should build amounts with describeAmount(raw, decimals, unit) from core/services/bigint-math.ts.

• 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

"Deposit 500 USDT into the JustLend V2 vault" (Moolah) → AI uses moolah_supply prompt: lists vaults with APY → selects USDT → checks allowance → calls approve_moolah_vault → calls moolah_vault_deposit → verifies shares via get_moolah_vault

"What's my risk on the TRX→USDT market?" (Moolah) → AI calls get_moolah_user_position for the market, interprets the risk ratio (0–1 where 1.0 = liquidatable), warns at >0.85

"Find me a liquidation opportunity" (Moolah) → AI calls get_moolah_pending_liquidations with minRiskLevel=1.0 → for a target, calls get_moolah_liquidation_quote → estimates profit → if viable, guides through approve_liquidator_token + moolah_liquidate

"How much did I supply to JustLend in the last month?" → AI calls get_lending_records paginated and filters action type 1 (supply) from the returned actionName

Changelog

See CHANGELOG.md for the per-version history (Keep a Changelog format, SemVer).

License

MIT License Copyright (c) 2026 JustLend SPDX-License-Identifier: MIT