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

With no annotations, the description carries the burden. It discloses that the tool performs deterministic math, which implies no side effects or randomness, and clarifies that it does not quote lender terms, setting expectations. It does not detail error handling or edge cases, but for a calculator that's acceptable.

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 two concise sentences that front-load the purpose and method, with no redundant information. It efficiently communicates the essential behavior and boundary.

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?

The description explains the output concept (minimum of constraints and which binds) which is essential since there is no output schema. It also sets the boundary that it doesn't quote lender terms. It doesn't specify the exact return format, but the concept is clear enough for an agent to use the tool.

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?

The description mentions the four constraints (LTV, DSCR, debt yield, LTC) which correspond to the thresholds object parameters, adding context beyond the schema's dry property descriptions. However, it does not elaborate on the individual input parameters like NOI or estimated value beyond what the schema already states, so the added value is moderate.

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 clearly states the tool's function: sizing a commercial real estate loan from first principles, and specifies the method (minimum of four constraints) and the output (max supportable loan plus binding constraint). This distinguishes it from sibling tools like compare_loan_offers or calculate_payment, which serve different purposes.

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 usage for loan sizing from first principles and explicitly states it does not quote lender terms, which hints at boundaries. However, it does not name specific alternative tools or provide explicit when-to-use/when-not-to-use guidance beyond that boundary, so it's only partially informative.

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