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

Annotations already mark this as a safe read-only, idempotent operation, so the description goes further: it discloses the 1000-block scan cap, that results are truncated with a flag, and critically that logs come from receipts which only exist for a rolling window (~6 days) with older ranges refused. This is exactly the kind of non-obvious failure boundary an agent needs.

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?

Dense but fully front-loaded and segmented into When to use / Do not use / Returns / Boundary. Every sentence carries distinct information with no filler.

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 enumerates the return envelope (filter, matched, returned, truncated, logs[] fields) and documents the receipt-availability boundary, so an agent has everything needed to call it and interpret results.

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 description coverage is 100%, so the schema already documents all five parameters including defaults, so the baseline is 3. The description restates the address/topic0 filters and the block-range filters but adds little param-level syntax beyond what is in the schema.

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 and resource ('Ethereum event logs over a block range') plus the optional filters, and implicitly distinguishes itself from eth_get_transaction and eth_get_block. The added decoding detail (ERC-20 Transfer logs decoded to token/from/to/amount) makes the scope unambiguous.

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?

Explicit 'When to use' with a concrete example ('who moved this token in the last N blocks') and an explicit 'Do not use' naming the alternative (eth_get_transaction) and the constraint against huge ranges. Both the positive and negative cases are spelled out.

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