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

With no annotations, the description carries the full behavioral burden and does well: it discloses the payment requirement and mechanism (x402, USDC on Base), the data provenance (Coinbase public price APIs), and the edge-cache window (up to 30s). It stops short of describing failure/error behavior or latency expectations beyond caching.

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?

A single dense sentence with the cost, resource, examples, provenance, and caching front-loaded. Every clause earns its place, with no padding.

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 one-parameter, no-output-schema tool, this covers cost, source, and freshness, which is what an agent needs to decide and invoke. It lacks only explicit sibling discrimination and error-handling notes.

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% and the single symbol parameter is already documented as BASE-QUOTE with format guidance. The description reinforces the format via examples but adds little beyond what the schema already provides, so baseline 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?

Specific verb+resource: fetches a live crypto spot price in USD for a BASE-QUOTE pair, with concrete examples (BTC-USD/ETH-USD/SOL-USD). It is clear and unambiguous, though it never explicitly distinguishes itself from the sibling get_usd_price, leaving a minor routing question for an agent.

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 description flags that the call is paid ($0.001 via x402/USDC Base), which is a meaningful usage consideration, but it never states when to use this over alternatives or any preconditions. Usage is only implied by the resource it fetches.

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