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

Annotations already declare readOnly/idempotent/closed-world, so the safety profile is covered. The description goes beyond them by disclosing the exact return shape, the EVM-vs-Solana keying asymmetry, and the practical warning that output can be large with many wallets — a useful cost/volume signal not present in 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?

Two sentences, no filler, and the resource scope is front-loaded ahead of the return-format detail. Slightly dense — the return-shape clause packs chain-id keying, Solana placement, and a volume caveat into one sentence — but every element earns its place.

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?

There is no output schema, so the description carries the return-value burden and does so adequately (array of { walletAddress, data }, with the EVM/Solana split). The large-output warning is a good operational caveat; only a hint about pagination or handling that volume is absent.

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?

The tool takes zero parameters and the schema is empty, so there is nothing to document; the description correctly does not invent parameter guidance. The note that wallets are sourced from wallet_list instead explains the implicit input, which is the only parameter-adjacent concept that needed covering.

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+resource (token balances) and an exact scope: every user wallet, all supported networks. An agent can immediately separate it from the sibling portfolio tools (portfolio_cex, portfolio_defi, portfolio_transactions) which cover exchange, DeFi, and transaction data rather than plain token balances.

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 when to use it (need a per-wallet token balance snapshot) and helpfully notes the addresses originate from wallet_list, linking it to a sibling. However, it never states when NOT to use it or which sibling to prefer for a narrower query, so the routing guidance is only implied.

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