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

Annotations already declare readOnly, idempotent, and closed-world retrieval, so safety is covered. The description adds useful context that the data comes from 'our own node' and lists the exact fields returned, though it doesn't disclose staleness/block-tag behavior (latest vs pending).

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?

Three front-loaded blocks (what it does, when to use, when not to use, returns) with no wasted words. The scope statement leads and the disambiguation follows immediately.

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 returned fields (address, balance_eth, nonce, is_contract, code_size_bytes), fully compensating. For a single-param read with annotations covering safety, nothing an agent needs 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 description coverage is 100% and the single address parameter already documents the '0x + 40 hex address' format. The description adds no further parameter semantics, so baseline 3 applies for a one-param, fully-documented 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+resource ('Ethereum account state') and enumerates exactly what it retrieves: ETH balance, nonce, and contract status. It differentiates itself from siblings by naming eth_read_contract and the risk-scoring tool as out of scope.

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' and 'Do not use' sections with concrete alternatives: eth_read_contract with balanceOf for ERC-20 balances, and a separate tool for address risk scoring. An agent knows precisely when to route here.

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