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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, covering safety and idempotency. The description adds context about the rolling 24-hour window and the inclusion of 30-day volume, which is useful but not extensive. It does not contradict annotations.

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 a concise two-sentence statement, front-loaded with the primary function and followed by a useful usage note. Every word contributes value with no redundancy.

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 simple read-only tool with one parameter and an output schema, the description is largely complete. It explains the key data points and suggests a use case. It lacks explicit alternative differentiation, but given the richness of annotations and output schema, it is not a critical gap.

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 schema has 0% description coverage, so the description must compensate. It states 'for a crypto pair' which links the product_id parameter to a trading pair, but it does not specify the exact format (e.g., 'BTC-USD') beyond what the schema example already provides. This is adequate but not thorough.

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 states the tool retrieves 'Coinbase Exchange 24-hour rolling stats for a crypto pair' and enumerates the specific data points (open, high, low, last, volume, 30-day volume). This distinguishes it from sibling tools like product_ticker or product_candles, which focus on different aspects of product data.

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 phrase 'Use for daily summary' provides a clear usage context, implying this tool is appropriate for periodic summaries. However, it does not explicitly mention when not to use it or name alternative tools, so it falls short of a 5.

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