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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered; the description adds the meaningful extras — that the listing is itself free ("Free.") and that pricing is quoted in USDC per call. It doesn't state ordering or whether the catalog is stable across calls, but the annotation coverage lowers the bar.

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 core purpose and the "before you spend anything" trigger are front-loaded, but the middle sentence is a sprawling run-on enumeration of data domains (permits, bridge wait times, peso, diesel, alcohol sales, home health agencies) that costs significant length for marginal selection value. It earns some of its place by conveying coverage, but not all of it.

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 full burden of describing return values, and it does so explicitly: price per call, what the call returns, example question, parameters with valid values, and a free sample URL. Nothing an agent needs to call this zero-param tool is missing.

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?

Zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly implies the tool takes no input by framing it as a full catalog dump.

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 ("List every paid Frontera Signal endpoint") and scopes it to a concrete domain (Rio Grande Valley, Texas market data). An agent knows immediately what it gets back: a catalog of priced endpoints with per-call cost in USDC, return description, example question, parameters and a free sample URL.

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?

"before you spend anything" gives a clear condition for calling it: discovery prior to any paid invocation. It does not explicitly name the siblings (get_free_series, get_sample, how_to_pay) or say when to prefer them over this one, so routing between the free-sample path and the catalog is left implicit.

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