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

Goes beyond the annotations by disclosing the 100-log return cap, the fields returned (block, transaction hash, topics), and the pricing model ($0.01/call via x402 USDC or card key, first 25 free, failed calls free). The note that 'each call is charged, so repeats are not free' usefully corroborates the idempotentHint=false annotation. The closing 'Reads or computes only and changes nothing' merely restates readOnlyHint and earns no credit.

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 purpose and the eth_getLogs analogue, then scope, return shape, the alternative, an example, and pricing. Every sentence is doing a distinct job; the only slack is the redundant read-only restatement at the end.

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 no output schema, the description steps in to describe the return shape and the 100-log truncation cap, and it covers cost and the alternative tool. A brief note on what happens when more than 100 logs exist in the block window would make it fully complete, but an agent has enough to call it correctly.

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%, so the schema already documents blocks (1-1000, default 50) and topic0. The description adds only marginal detail ('0x 32-byte event signature hash') and an example address value, which is correct but thin given the schema already carries the range and defaults.

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?

Names a specific verb+resource ('Recent contract event logs ... eth_getLogs') and states the exact scope: events a contract emitted over the last N blocks, optionally filtered by topic0. It also explicitly distinguishes itself from the sibling hyperevm_receipt for single-transaction outcomes, 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?

Gives explicit usage ('Use to watch transfers or contract events') and names the alternative plus the condition that selects it ('for one transaction's outcome use hyperevm_receipt'). It even supplies a concrete address example, 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.