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

Annotations cover only readOnly/openWorld, but the description adds the price source (slot0, deepest pool), what it returns (pool/fee tier, USD depth), the absence of an off-chain feed, a manipulation caution, and per-call cost with a free first call. This is substantial context beyond the 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?

Purpose is front-loaded, followed by caveats, alternative routing, and cost. Every sentence carries signal, though the middle clause is dense enough that it reads slightly packed rather than cleanly scannable.

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?

No output schema exists, but the description names the returned fields (pool/fee tier used and USD depth), the data source, and the cost model, which is everything an agent needs to invoke it correctly and interpret the result.

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?

Only one parameter, and schema description coverage is 100%, so the schema already fully documents tokenAddress. The description reinforces 'single ERC-20 on Base' but adds no syntax or format detail beyond that, so the 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 for a single ERC-20 on Base') and pins the data source (deepest Uniswap v3 pool vs USDC/WETH, slot0). It explicitly distinguishes itself from the sibling multi-token-price, so an agent can route without opening either schema.

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?

Names the alternative tool and the exact condition that selects it ('To price MANY tokens at once, use multi-token-price instead'). Adds the thin-pool manipulation caveat as a usage warning, leaving little to inference.

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