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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so safety is covered. The description adds real context beyond that: data coverage breadth (400+ coins, multi-currency), the pricing model (x402 or prepaid credits, free trial), and interpretive framing such as 'fast redemptions (supply falling, often a run)'. It stops short of describing pagination or rate limits.

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?

A single dense but front-loaded sentence enumerates the reports, followed by one short pricing sentence. No filler, though the long enumeration is heavy and could be trimmed slightly.

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 values need not be explained, and annotations cover the safety profile. The description supplies coverage scope and cost, which are the main things an agent needs to decide to call. Minor omissions (pagination, default thresholds) are acceptable given the structured fields.

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 schema already documents peg, limit, symbol, minSupplyUsd, and thresholdPercent. The description hints at concepts behind them ('how badly', 'fast redemptions', '10 largest') but adds no syntax, defaults, or format detail beyond the schema. Baseline 3 is appropriate.

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 (monitor stablecoin depegs) with clear scope: 400+ USD/EUR/GBP and other stablecoins. It enumerates the exact outputs an agent can expect (off-peg coins and severity, fast redemptions, premiums, top-10 status), which cleanly separates it from siblings like token-price or token-safety.

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 context is implied by the content (checking which stablecoins have lost their peg), but the description never states when to pick this over alternatives like token-safety or token-price, nor any exclusions or prerequisites. No explicit when/when-not guidance.

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