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

No annotations are provided, so the description carries the full burden. It discloses that data is 'live from Blockscout', mentions the cost ($0.003 via x402), and implies it is an on-chain RPC read (which suggests a read-only operation, but it does not explicitly state safety). It also reveals the scope of chains. This extra information adds context beyond what annotations would typically provide, even though annotations are missing. It is not misleading; however, it could be more explicit about being a read-only operation.

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 somewhat long but front-loaded with the key benefit (core on-chain RPC read) and then provides details about the data included and chain coverage. It is structured but could be trimmed for clarity. However, every sentence adds value—no fluff.

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 moderate complexity (6 chains, output includes balance, USD value, transaction count), the description covers the essential functionality. It does not explain output format, but no output schema is given, so the description is the only source. It mentions they are 'live' and 'from Blockscout', which is good. It could mention pagination or rate limits, but for a balance check tool, this is adequate.

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 67% (two of three parameters are described). The description adds the meaning of the address and chain, specifying the chain options and default. It does not describe the x_payment parameter, but that is likely a payment mechanism and not essential for the core functionality. The description adds meaning for the chain parameter beyond the schema's description, but the coverage is not 100%, so the description partially compensates.

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 what the tool does: reads the native coin balance for any address across multiple chains, providing live USD value and outgoing transaction count. It explicitly distinguishes from sibling tools, especially noting the comparison to 'onesource's Ethereum-only' tool and the 6 chain support.

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 the use case: high-frequency balance checks for wallet-tracking, settlement, and trading agents. It contrasts with a sibling tool (onesource) but does not explicitly mention usage exclusions or specifics like when to use alternatives. It says 'vs onesource's Ethereum-only' which is a clear alt hint, but no explicit when-to-use vs other chain tools.

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