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

Goes well beyond the readOnlyHint/openWorldHint annotations: names the data source (CoinGecko public aggregate price), discloses the snapshot nature and its blind spots, and spells out the paid-call mechanics — $0.002 USDC per successful call via x402 on Base/Solana/Arc, with failed calls uncharged. That cost and failure-billing detail is exactly what an agent needs before invoking a paid endpoint.

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?

Three tight sentences: what it returns, how it classifies thresholds, what it excludes, and what it costs. The most decision-relevant facts (price, peg deviation) are front-loaded with no filler.

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 an output schema present, return-shape explanation is unnecessary, and the description covers source, thresholds (0.15% MICRO_DEPEG, 1% DEPEG), limitations, defaults, and billing. Nothing an agent needs to call it correctly or budget for it 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?

The single optional parameter is fully documented in the schema (100% coverage), so the baseline is 3. The description adds real value by giving the human ticker symbols (USDT, USDC, DAI, FDUSD, PYUSD) that map onto the schema's CoinGecko slugs (tether, usd-coin, ...), reducing selection errors.

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+resource: current USD price and deviation from the $1 peg for an enumerated coin set (USDT, USDC, DAI, FDUSD, PYUSD). The scope is narrow and unambiguous, letting an agent distinguish it from the many other agent_intel crypto tools.

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?

Explicitly bounds the tool's applicability by disclaiming what it does NOT cover (no per-pool Curve imbalance, no redemption-liquidity data), which tells the agent when this snapshot is insufficient. It stops short of naming a specific sibling tool to use instead, so no explicit alternative routing is given.

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