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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds the deduction logic (what is subtracted to reach net cash), which is genuine behavioral context, but says nothing about how the new loan is sized under max_ltv/min_dscr or whether the result can be zero or negative.

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 key quantity front-loaded and no filler. It reads as a noun phrase rather than a complete directive, which slightly weakens the lead.

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?

For a 10-parameter financial calculation with no output schema, the description does state what is returned, which is the most important piece. It omits the loan-sizing mechanics implied by value/max_ltv/noi/min_dscr/rate/amort and any handling of constraint-binding or negative proceeds.

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 parameter is already documented in the schema; the description only echoes four of the ten (payoff, prepayment, closing costs, reserves) and adds no unit or format detail. Baseline 3 applies when the schema carries the semantic load.

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 names the exact quantity computed — net cash to the borrower from a cash-out refinance — and enumerates the deduction components (payoff, prepayment, closing costs, reserves). That is specific enough to separate it from siblings like size_loan or refinance_break_even, though it never uses an explicit verb such as 'computes' and does not name those siblings.

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?

There is no guidance on when to call this versus size_loan, refinance_break_even, or compare_programs. The agent must infer from the description alone that this is the proceeds-calc tool, with no stated preconditions or exclusions.

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