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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real value by enumerating the computed outputs (profit, cash-in, return on cash, 70% rule check, breakeven price), which is the behavioral detail an agent needs since no output schema exists.

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 action is front-loaded in the first clause and the rest is a dense but purposeful enumeration of returned metrics. The long comma-chained list is slightly heavy to parse but every element earns its place as output disclosure.

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?

With 17 parameters and 100% schema coverage but no output schema, the description correctly fills the remaining gap by describing what the calculator returns. Only minor items, such as how lender names are resolved or error behavior when both lender and rate_pct are supplied, are left implicit.

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%, so every one of the 17 parameters is already documented with defaults, ranges and enums. The description only restates the lender-rate option and lists outputs; it does not add interpretive meaning to any parameter beyond the schema. Baseline 3 applies.

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 and resource ('Runs the fixandflip.loans calculator on a deal') and enumerates the outputs produced, so the tool's function is immediately legible. It does not, however, distinguish itself from siblings like compare_lender_costs or get_lender_terms, which is the main thing keeping it below a 5.

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 clause 'Optionally prices the loan at a listed lender's advertised starting rate' implies usage around the lender parameter, but it never says when to prefer this over compare_lender_costs or how to obtain a valid lender name. There are no explicit when-not conditions or alternative routing.

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