Fabrica (Sepolia testnet)

Prepare a loan against land

borrow_against_land

Prepare borrowing USDC from the DeFi lending pool against a property the wallet holds (Sepolia Testnet), for amountUsd over durationDays (the pool's offered length closest to it, default about 30 days). Checks first that the wallet holds the token, the property backs no active loan, the pool lends against it and the amount is within the pool's current maximum (estimate_land_borrowing shows it). The rate and repayment come from the pool's live quote on the sign page. This is a test loan on Sepolia with no real-world effect. Prepared, not sent: returns a signRequest (summary, warnings, signLink to fabrica.land, expiresAt 15 minutes out, payload null for now) and stores it so the sign page can load it. The person opens the link, signs in with that wallet and signs; nothing happens until then. The server holds no keys and submits nothing. wallet is the address that will sign.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "amountUsd": "<amountUsd>",
      "wallet": "<wallet>"
    },
    "name": "borrow_against_land"
  }
}

Input Schema

Name	Required	Description
`slug`	No	Property slug from the URL
`wallet`	Yes	The wallet that will sign (0x address). The sign page only lets this wallet sign.
`tokenId`	No	The token ID of the property
`amountUsd`	Yes	Principal to borrow in US dollars, paid in USDC; at most what estimate_land_borrowing shows as maxBorrow
`durationDays`	No	Loan length in days. The sign page uses the pool's offered length closest to it (default: the one closest to 30 days)

Schema Changelog

Changes observed during successful MCP inspections.

AddedOct 23, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Discloses substantially more than the annotations: returns a signRequest (summary, warnings, signLink, expiresAt 15 minutes, payload null), stores it for the sign page, requires the user to open the link and sign, holds no keys, and submits nothing. This is exactly the behavioral context an agent needs for an openWorld, non-idempotent prepare step.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads purpose and scope, then prerequisites, then return/lifecycle. Dense and slightly run-on in the middle (parenthetical about estimate_land_borrowing and the signRequest details), but nearly every sentence carries distinct information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 5-parameter, no-output-schema prepare tool, the description covers prerequisites, return shape, expiry, who signs, and that nothing is submitted server-side. Nothing an agent needs to invoke it correctly appears missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents parameters; the description still adds meaning by clarifying that wallet is the signer, durationDays maps to the pool's closest offered length (default ~30 days), and amountUsd is bounded by the pool's current maximum.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Prepare borrowing USDC from the DeFi lending pool against a property the wallet holds') and pins the scope to Sepolia and to a prepared-not-sent flow. This clearly separates it from siblings like estimate_land_borrowing, get_land_loan, and repay_land_loan.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear context for when to use it — pre-checks performed (wallet holds token, no active loan, pool lends against it, amount within max) — and points to estimate_land_borrowing as the way to learn the max borrow. Lacks explicit 'when not to use' exclusions, but the workflow and alternative are unambiguous.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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