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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds useful behavioral context: reads are performed at a single resolved block, and only 'official USDC' is considered, which goes 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?

The description is a single, well-structured sentence with no superfluous words. It front-loads the main purpose and lists specific outputs efficiently.

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?

Given the tool's simplicity, the presence of a rich output schema, and strong annotations, this description covers all essential aspects. It explains what the tool does, what data it returns, and the consistency guarantee of a single resolved block.

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%, with both parameters clearly documented in the schema. The description's phrase 'single resolved block' echoes the schema's block_tag description but does not add new parameter-level information.

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 clearly states the tool checks a specific Base mainnet wallet or contract and lists the exact data returned: ETH and official USDC balances, transaction nonce, and contract-bytecode evidence. This specificity distinguishes it from generic siblings like crypto.base-account-snapshot.

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?

The description implies usage when these specific account attributes (balances, nonce, bytecode) are needed, but it does not explicitly mention alternatives or provide when-not-to-use guidance. The sibling list includes similar tools, so more explicit differentiation would improve this dimension.

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