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

Annotations already cover read-only/idempotent safety, and the description layers substantial extra behavior on top: $0.003 USDC per call via x402, errors are free, no API key needed, live mainnet RPC source, deterministic token ordering, null instead of invented values, a mandatory disclaimer, and 400 with no charge on invalid input. That is an unusually complete disclosure of cost, error, and data-integrity semantics.

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?

It is dense and reasonably short, but it is front-loaded with pricing and billing mechanics rather than the tool's purpose, so the most decision-relevant sentence is buried mid-paragraph. The bracketed cost notice takes the prime position.

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?

With no output schema, the description must carry the burden of explaining return values, and it only gestures at them (token ordering, null for unavailable, a disclaimer field) without saying whether native SOL balance, NFTs, or other holdings are included. For a wallet-inspection tool this leaves a meaningful gap in what the agent can expect back.

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% and the single `address` parameter is documented as a base58 Solana wallet address in the schema itself. The description adds only indirect validation context ('Invalid input = 400, never charged') and nothing about address format, so the schema does the real work.

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 never states outright what the tool returns; the reader has to infer from 'Tokens sorted known-first then by amount; USD values not computed' that this is a Solana wallet holdings lookup. Sibling tools like base_wallet_balances and sol_token are not referenced, so the agent must infer the split from the name alone.

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 explicit when-to-use or when-not-to-use guidance, and no routing to alternatives such as base_wallet_balances for Base wallets or address_brief. The only usage-relevant information is the payment and no-API-key note, which is context rather than selection guidance.

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