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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered; the description adds value by listing the outputs and disclosing the CCN auto-fill convenience behavior. It does not mention that rate is a user assumption rather than a HUD-set figure (that lives only in the schema), leaving a small gap.

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?

Front-loaded with the operative verb and tightly packed — two sentences, no filler, and the return-value list is dense but useful. The first sentence is long and list-like, which costs a bit of scannability.

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 15 parameters and no output schema, the description carries the return-value burden itself and does so explicitly (max insurable loan, binding test, payment, MIP, DSCR, cash to close). Combined with the 100% schema coverage, an agent has everything needed to call it correctly.

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% and every parameter carries its own default/range notes, so the schema does the heavy lifting. The description only restates the input categories (NOI, value, rate, payoff) and the CCN fill rule, which the schema already describes, so it adds little beyond the baseline.

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 SNF Register sizer for HUD Section 232 loan tests — and enumerates the exact tests (1.45x/1.11x DSCR, 80/85% LTV, cost to refinance, 223(a)(7) original principal). No sibling tool does sizing, so the distinction is implicit but unambiguous.

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?

Gives conditional usage: 'Pass a CCN to fill in its active FHA loan,' and the program/track distinction is inferable from the enumerated test set. It does not name sibling alternatives (e.g. use search_nursing_homes to obtain the CCN in the first place) or state when-not to use it, so it stops short of a 5.

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