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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing per-call cost ($0.002 USDC, x402 on Base/Solana/Arc) and that failed calls are not charged. It also clarifies that net change is supply change, not separate mint/burn events, preempting a misinterpretation of the metric.

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?

Dense but front-loaded with the metrics first, then invocation, then pricing caveat. A few clauses are packed together, yet every part carries information; 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?

Output schema exists so return values needn't be described; with one fully documented parameter, read-only annotations, metric definitions, and payment terms, an agent has everything needed to call and interpret it correctly.

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% and the description largely repeats it (comma-separated tickers, up to 10, default 10 largest). It adds a small example (USDT,USDC) but no new semantic depth beyond the schema.

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 specific metrics (circulating market cap, 1/7/30-day circulating change, peg price, depeg %) and the source (DefiLlama), which separates it from siblings like crypto_defillama_tvl_oracle and crypto_defillama_yields. It's a data-retrieval tool, so the absence of a single verb is fine, but it doesn't explicitly contrast against those siblings.

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?

Explains how to invoke: pass symbols or leave empty for the 10 largest. But it never says when to choose this over the TVL or yields DefiLlama tools, nor any conditions favoring it beyond the obvious subject matter.

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