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

Annotations already declare readOnly, idempotent, and closed-world. The description adds a genuinely useful behavioral trait beyond them: the null-fidelity rule that absent figures are reported as absent rather than filled in. That directly informs how an agent should interpret returned data.

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 and dense, but it redundantly re-enumerates all eight program keys that the schema already lists, which inflates a single sentence considerably. The fidelity clause earns its place; the enum restatement does not.

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 no output schema, the description carries the return-value burden and does so reasonably: it names the fields returned (parameters, starting rate with as-of stamp, page URL) and the null-handling rule. Only the routing question of when to prefer this over rate_ranges or investor_lenders_* is left unaddressed.

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 the single enum parameter and its 'omit for all' behavior are already fully documented. The description repeats the enum list in prose without adding format, defaulting, or filtering semantics beyond what the schema provides.

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 resource (the National Loan Provider program set) and enumerates exactly what each entry contains: published parameters, starting rate with as-of stamp, and page URL. This clearly distinguishes it from siblings like rate_ranges or about_national_loan_provider, though the description never uses an explicit verb such as 'returns' or 'lists'.

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?

No when-to-use guidance and no named alternatives among the siblings. The only quasi-guidance is a data-fidelity rule ('where a page states no figure, the tool states no figure'), which describes output behavior rather than selection context. An agent must infer that omission of the program key returns all programs.

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