I used the same url for two different postings.
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 (readOnlyHint, openWorldHint, idempotentHint) already cover the tool's non-mutating, deterministic nature. The description adds a key behavioral detail—the $0.0005 USDC cost per call—which is not present in the annotations and helps the agent anticipate charges.
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?
The description is a single sentence with no filler: it front-loads the core action and metrics, and tucks the cost into a parenthetical. Every word earns its place.
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?
Given the simple two-parameter schema, provided output schema, and annotations covering safety, the description supplies the essential purpose and cost. It doesn't justify the formulas or data sources, but an agent can invoke the tool correctly with the information given.
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 purchasePrice and monthlyRent both described. The description adds that these inputs feed into the listed financial metrics but offers no parameter-specific details beyond the schema, so it meets the baseline without exceeding it.
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?
The description opens with a specific verb 'Calculates' and names the exact financial outputs (NOI, Cap Rate, Monthly Cash Flow, DSCR) for real estate deals, which clearly distinguishes it from the sibling property_comps_estimator. An agent can immediately understand the tool's function without consulting schemas.
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?
The description implies the tool is used when an agent needs these specific real estate financial metrics, but it provides no explicit guidance on when to choose it over alternatives like property_comps_estimator, nor does it mention prerequisites or exclusions. Usage context is inferred rather than stated.
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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