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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds substantial context on top: the $0.02 per-call x402 cost on Base, the prepaid x-credit-token header for unlimited calls, 1 free call/day per tool, and that no API key is required. Payment and auth behavior is exactly what annotations cannot convey.

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?

Front-loaded with the core capability and batch limit, then payment mechanics. Dense but every clause is relevant; 'No API key required' is mildly redundant given the x402/header explanation, keeping it out of 5 territory.

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?

An output schema exists, yet the description still names the return shape (USD price + 24h change), and it covers chain scope, batch ceiling, cost model, and auth. Nothing needed to call this tool correctly is missing.

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 coverage is 100% for the single 'addresses' parameter, so the baseline is 3. The description adds value beyond the schema by stating the 10-address maximum and restricting inputs to Base token addresses, which the schema's 'comma-separated' note does not convey.

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+resource with scope: batch pricing of 'up to 10 Base tokens at once', returning USD price + 24h change. It is clearly distinguishable from single-token siblings like token_price or pair_info because the batch size and chain are explicit.

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?

'Ideal for agents pricing a portfolio or watchlist' gives clear usage context, and the up-to-10 limit implicitly tells the agent when to use it over a single-token call. It never explicitly names an alternative tool or a when-not-to-use condition, so it stops 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.