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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior. The description adds genuine context beyond that: rates come from a single site rate source with an as-of stamp, and the honesty clause ('where a page states no figure, the tool states no figure') tells the agent to expect nulls rather than fabricated values.

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 enumerations and provenance details are front-loaded in a dense but waste-free pair of sentences. Slightly heavy for a read tool, but every clause (rate source, as-of stamp, URL, null policy) earns its place.

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 does the work of describing the return shape (per-program parameters, starting rate, page URL) and the null-handling policy, which is enough for an agent to call it correctly. It stops short of specifying the response envelope or whether rates are numeric or strings.

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 the single program parameter is fully documented there, so the description's re-listing of the same keys adds no new syntax or semantics. Baseline 3 applies when the schema does the heavy lifting.

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 specific resource (the National Loan Provider program set) and enumerates exactly what each record contains: program parameters, starting rate with as-of stamp, and page URL. The purpose is unmistakable, though it does not explicitly contrast itself with siblings like rate_ranges or investor_lenders_aggregate.

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?

Usage is implied by the content (fetch published loan-program specs and starting rates), but the description offers no when-to-use guidance and never names an alternative tool such as rate_ranges for rate-only queries. The optional program filter is the only routing signal an agent gets.

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