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

Annotations cover read-only and open-world safety, but the description adds critical non-annotation behavior: it is pay-per-call via x402 USDC on Base, and a missing payment returns a payment challenge. This is exactly the kind of operational detail an agent needs and is not in the annotations or schema. It doesn't cover rate limits or error modes beyond payment, so not a 5.

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 tightly written sentences front-load the aggregation scope and then the payment model. Every phrase earns its place; no redundant restatement of the name or title.

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, the description does not need to detail return fields; it focuses on the aggregation promise and the payment requirement. Annotations already carry safety, and the schema documents the symbol parameter fully, so the definition is sufficient for correct invocation.

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% for the single optional symbol parameter, including the BTC default. The description adds no additional syntax, format or semantic detail beyond the schema, so the baseline of 3 applies.

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 names the resource (market pulse) and enumerates the exact metrics returned—price, 24h change, volume, cross-venue funding and OI—so the agent knows what it does. It differentiates from single-metric siblings like funding and open_interest by emphasizing 'One call' aggregation, though it doesn't name those siblings explicitly.

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 'One call' implies the tool is an aggregate alternative to calling separate tools, but the description never states explicit conditions for using it versus siblings like btc_stats, funding or open_interest. No when-not or prerequisite guidance is given, leaving usage to inference.

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