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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds an important non-schema behavior: a concrete $0.005 USDC cost via x402. It doesn't mention return ordering or result limits, but for a safe read operation the description adds meaningful value beyond 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?

Two tight sentences with no filler; the core action and scope come first, with the cost disclosure at the end. Every sentence contributes.

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 100% schema coverage, the required address parameter, read-only annotations, and a clear statement of scope and cost, an agent has enough to select and invoke the tool. Return shape is not described, but no output schema exists and the expected result (event logs) is inferable from the tool's purpose.

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 already documents address, topics, from_block, and to_block. The description restates those as 'by contract address, topics and bounded block range' but adds no syntax details beyond the schema, matching the baseline.

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 opens with the specific verb 'Query' and names the resource: smart-contract event logs on Base, scoped by contract address, topics, and block range. This clearly distinguishes it from siblings like base_receipt or base_transaction.

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?

It clearly signals when to use the tool: whenever event logs for a Base contract are needed over bounded block ranges. It does not explicitly name alternatives or exclusions, but the stated scope leaves little ambiguity about its niche among sibling tools.

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