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

With no annotations, the description does carry the full burden, but it does disclose genuinely useful behavior: the $0.01 USDC x402 charge per call and the Blockscout data source behind the six chains. It is silent on failure modes, rate limits, and what happens if a chain has no activity, so the disclosure is partial rather than complete.

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?

A single dense sentence with the cost signal bracketed and front-loaded, followed immediately by the payload contents and chain coverage. Nothing is padded and the most decision-relevant facts appear first.

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?

For a two-parameter read tool with no output schema, the description does the required work by enumerating the returned fields so the agent knows a portfolio summary comes back rather than a raw transfer log. Only error and edge-case behavior remain unaddressed, which is a minor gap at this complexity.

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 both parameters and the chain list, which sets the baseline at 3. The description adds the meaningful detail that results span multiple chains simultaneously and that pricing and valuation are attached to token balances, which is more than a restatement of the parameter text.

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 names a concrete resource (EVM wallet portfolio) and enumerates exactly what comes back: native balance, ERC-20 balances with USD prices and total value, and tx count, plus the supported chains. That is specific enough to separate it from siblings like price, token_pairs, or token_risk, though it reads as a contents list rather than a verb-led statement.

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?

There is no statement of when to pick this over sibling tools such as price or stablecoins, and no prerequisites or exclusions. The only contextual cue is the per-call price and the chain coverage, from which an agent must infer that this is a multi-chain address-level lookup.

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