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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds substantive context not in the annotations: the price ($0.005 USDC per successful call), the x402 payment rails (Base, Solana, Arc), and that failed calls are not charged. It does not say what happens on a date with no data or how many hourly points to expect, which keeps it from a 5.

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?

Purpose is front-loaded in the first clause, followed by sibling disambiguation and then pricing. Every sentence carries information an agent needs. The single dense block structure and the slightly buried pricing detail keep it from a 5.

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?

An output schema exists, so return-value explanation is not required, and pricing/payment behavior is documented. For a read-only two-parameter historical metrics tool this is close to complete. Minor gaps remain around empty-date handling and series length, but nothing that would cause a miscall.

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 coverage is 100%: both parameters carry descriptions, an enum for metric, and a regex pattern for date, with defaults documented. The description largely restates the metric list and UTC date format already in the schema. It adds no new semantics such as what 'trend' is computed over or whether a missing date falls back to the previous UTC day.

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 a specific verb-and-resource pair: an hourly time series plus summary statistics (min, max, average, trend) for four named Kaspa on-chain metrics, scoped to a UTC date. The list of metrics and the statistic types make the tool distinguishable from siblings such as crypto_kaspa_hashrate and crypto_kaspa_supply without opening any schema.

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?

A dedicated 'Related tools... for a different need' sentence routes the agent explicitly: use crypto_kaspa_hashrate for current network hashrate and all-time peak, and crypto_kaspa_supply for supply metrics. That covers the when-not case for the two closest siblings. It stops short of a blanket statement like 'use this only for historical daily granularity', which would make it a 5.

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