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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the bar is lower. The description adds genuinely non-structured context: the tool is paid ($0.05 in USDC on Base via x402) and the data window is bounded by 168 recorded hours of retention.

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?

Two tight sentences, front-loaded with the resource and granularity, with the cost disclosure placed last where it belongs. The mid-sentence field list is dense but every item is informative.

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 by listing the returned metrics. Combined with cost, granularity, and retention limits, an agent has enough to select and call the tool correctly; only currency/platform format guidance 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?

Schema description coverage is only 33% and the description compensates partially: 'up to the last 168 recorded hours' clarifies the retention ceiling behind the hours parameter. It adds nothing about the currency format (^[A-Za-z]{3}$) or the platform id syntax, and those remain schema-only.

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 precise resource (hourly public USDC liquidity depth history) and enumerates the returned fields (listed depth, sellers, best premium, largest order, banded depth), so an agent knows exactly what comes back. It does not explicitly distinguish itself from siblings like peerlytics_weekly_seller_rates, though the 'hourly' granularity hints at the contrast.

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?

Scope is implied: it serves one payment platform and one currency, capped at 168 hours. There is no explicit when-to-use vs. when-not guidance and no alternative sibling is named, so the agent must infer applicability.

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