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

Annotations already cover readOnly/idempotent/openWorld, but the description adds genuinely non-obvious behavior: spam/unverified airdrops are flagged so the agent doesn't report fake holdings, results are USD-ranked, and there is a metered cost (25 free calls/day then $0.01 USDC via x402). It stops short of pagination or rate-limit behavior.

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?

Front-loaded with the core purpose and mostly efficient, but the opening 'learn which tokens a wallet holds and how much' is immediately restated in the third sentence about listing tokens with amounts and values — one sentence of redundancy in an otherwise tight block.

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?

No output schema exists, so the description must carry return-value context; it names the returned fields (amount, verified, USD value) and points to an external explanation page. That covers the essentials, though it doesn't fully describe the response shape or headline values.

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%, so every parameter (wallet, network, how_many, include_empty) is already well documented in the schema. The description's example ({"wallet": ..., "how_many": 10}) restates rather than adds meaning, so this sits at the baseline 3.

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 concrete verb+resource ('lists a wallet's tokens') and pins down scope: SPL Token and Token-2022, exact amounts, verification status, USD value, ranked highest-value-first. That is enough to distinguish it from balance, token_account, find_token, and token_safety without opening any schema.

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 implied by 'Run to learn which tokens a wallet holds and how much,' and it hints at when to set include_empty ('only to find empty accounts, e.g. to close them'), but it never names an alternative sibling or states when NOT to use this tool (e.g. for a single token's safety, use token_safety). No explicit routing guidance.

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