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

Beyond the readOnlyHint/openWorldHint annotations, it discloses error behavior ('Tokens with no pool return an error entry'), the pricing model and that the premium is always paid, and the resolution source for each price. These are behavioral traits an agent could not derive from the annotations or schema.

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 paragraph that front-loads the core capability, then the alternative-routing rule, then cost. Every clause carries distinct information (scope, source, error case, price, limit) 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 no-output-schema tool, the description covers what the agent needs: batch size ceiling, data source, failure mode for pool-less tokens, and cost implications. Nothing required to invoke or interpret it 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% and there is only one parameter, so the schema already documents tokenAddresses and its max-15 constraint. The description repeats the batch limit rather than adding format or edge-case detail beyond the schema, 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?

States a specific verb+resource ('on-chain USD spot price') with explicit batch scope ('up to 15 ERC-20s in one call') and the data source (deepest Uniswap v3 pool vs USDC/WETH). It distinguishes itself from the sibling token-spot-price by naming it directly.

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?

Gives an explicit selection rule: 'Use this for 2+ tokens; for a single token use token-spot-price (cheaper).' The alternative and the condition that selects it are both stated, leaving nothing to inference.

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