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

With no annotations supplied, the description carries the behavioral burden well: it discloses the exact charge, payment currency and network, lack of account or API-key requirements, and the policy that failed calls are not charged. It also identifies Coinbase Exchange as the source and Kraken as a cross-check, adding meaningful provenance context.

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?

The description is compact and front-loads both the paid nature and the exact data scope. Each subsequent statement adds useful cost, access, failure-billing, provenance, or endpoint information without 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?

For a zero-argument market-data tool without an output schema, listing the returned metrics, sources, cost, and access requirements provides nearly everything needed for selection and invocation. Minor remaining gaps are the response format, precise freshness expectations, and how the Kraken cross-check affects the returned values.

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 tool has no parameters, so there are no undocumented inputs requiring explanation. The fixed COMP/USD pair and asset-specific URL reinforce that the call needs no asset or currency selection.

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 clearly identifies a live COMP/USD market-data lookup and enumerates the price, range, change, and volume metrics provided. The fixed COMP scope distinguishes it from other coin-specific siblings, although it does not explicitly differentiate itself from the generic buy_crypto_price tool.

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?

The 'COMP/USD live' scope and leading 'Paid' label give an agent clear context for selecting it when current Compound market data is needed. It does not explain when to prefer a sibling or when not to use it, such as for historical data or another asset.

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