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 the role of page/limit/vs_currency in shaping results, but discloses no error behavior, rate limits, or result-shape context beyond what the schema and output schema carry.

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 sentences, zero waste, front-loaded with purpose and followed by the sibling-routing sentence. Every clause earns its place.

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 a full schema, output schema, and safety annotations, the description covers what an agent needs to select and call the tool. It could mention pagination bounds (limit max 100) or result shape, but those are already in structured data, so the gap is minor.

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 slug, page, limit, and vs_currency in detail. The description only gestures at the three pagination/currency params without adding syntax or defaults. Baseline 3 is correct when the schema does the heavy lifting.

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 (Fetch) and resource (NFT collection rows for a CoinGecko NFT category slug), and explicitly distinguishes itself from coingecko_nfts (browse across categories) and coingecko_categories (fungible-coin categories). An agent can pick this tool over its siblings without opening the 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?

Gives explicit routing: use coingecko_nfts to browse across categories, coingecko_categories for fungible-coin categories. This states the when-to-use-this condition and names the alternatives, so nothing is left to inference.

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