Calculates NOI, Cap Rate, Monthly Cash Flow, and DSCR for real estate deals ($0.0005 USDC)
| Name | Required | Description | Default |
|---|---|---|---|
| monthlyRent | Yes | Expected monthly rental income in USD | |
| purchasePrice | Yes | Total property purchase price in USD |
| Name | Required | Description | Default |
|---|---|---|---|
| success | Yes | Calculation status | |
| analysis | Yes | Cap rate, NOI, and cash flow analysis object |
Changes observed during successful MCP inspections.
Input schema / properties / monthlyRent / descriptionAdded value: +"Expected monthly rental income in USD"Input schema / properties / purchasePrice / descriptionAdded value: +"Total property purchase price in USD"Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "analysis": {
+ "description": "Cap rate, NOI, and cash flow analysis object",
+ "type": "object"
+ },
+ "success": {
+ "description": "Calculation status",
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "success",
+ "analysis"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly=true, idempotent=true, destructive=false, closed-world, so the safety profile is covered. The description adds genuine behavioral context beyond that: the call costs $0.0005 USDC, which tells an agent this is a paid operation. It does not explain payment mechanics or any rate limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single tight sentence with the outputs and the cost front-loaded and zero filler. Nothing could be removed without losing information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Output schema exists, so return values need no explanation, and annotations carry the safety profile. The description covers purpose and price, leaving the only real gap as how NOI/DSCR can be derived from just purchasePrice and monthlyRent (hidden expense/loan assumptions) and any usage routing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% with only 2 parameters, so the schema already documents both inputs fully; the baseline is 3. The description adds no syntax or unit detail beyond what the schema provides, though it does imply these two inputs drive the listed metrics.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb ('Calculates') plus the exact metrics returned (NOI, Cap Rate, Monthly Cash Flow, DSCR) for a defined domain (real estate deals). This clearly separates it from siblings such as property_comps_estimator, which estimates comps rather than underwriting metrics.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No indication of when to use this tool versus the nearby property_comps_estimator, nor any prerequisites (e.g., which deal inputs are needed). The only context provided is that it costs money, which is not usage guidance.
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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