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

With no annotations, the description carries the full load and does well: it discloses that values are read live from Base, are formatted with each token's symbol and decimals, and — critically — that invoking it costs $0.005 USDC via x402. That payment disclosure is behavioral context an agent cannot get from the schema. It still omits error/edge behavior, e.g. invalid or non-ERC-20 token addresses, empty results, or whether pricing is per call.

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?

One dense sentence with zero filler: what is returned, how it is formatted, where it is read from, and what it costs. Nothing needs trimming and the core payload leads the sentence.

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 2-parameter read tool with no output schema, the description covers return shape (symbol and decimals formatting), data freshness (live), and cost. Remaining gap is failure/edge behavior for invalid token addresses or a mix of token types, which an agent would benefit from knowing.

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 both parameters are documented in-schema with regex patterns, so the baseline is 3. The description restates the 20-token cap and the output formatting, which adds mild value but no syntax or format detail beyond 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: reads native ETH balance plus up to 20 listed ERC-20 token balances on Base. The chain scoping ('Base wallet') implicitly separates it from eth_wallet_balances, arbitrum_wallet_balances and the other chain siblings, though it never names a sibling or explains the difference from base_wallet_profile.

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?

Usage is only implied: an agent can infer it applies when it needs balance data on Base and has an address plus an optional token list. There is no explicit when-to-use/when-not-to-use guidance and no pointer to alternatives such as base_wallet_profile or base_token_snapshot.

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