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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), and the description layers on genuinely new traits: results ranked by USD value, unverified/spam tokens flagged, empty accounts excluded by default, and a concrete cost model (25 free calls/day then $0.01 USDC via x402). The x402 pricing is behavior an agent cannot get from annotations or schema.

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?

Purpose is front-loaded in the first sentence and the spam-flagging rationale is useful. The four 'Inputs:' sentences largely duplicate schema text that the agent already receives, adding length without new information, but the structure remains scannable.

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 steps in to describe the return shape (exact amounts, verified flag, USD value where a price exists) and names the token standards covered. Cost, network defaults, and pagination-like limits are all told, so an agent has what it needs to call and interpret it.

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 the schema descriptions are actually richer than the prose (e.g. wallet 'Not a .sol name or a ticker', include_empty rationale). The description essentially restates wallet/how_many/include_empty/network without adding format or edge-case meaning 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 — reading which tokens a wallet holds and how much — and immediately disambiguates from siblings like balance by scoping to SPL/Token-2022 holdings rather than native SOL. The mention of USD ranking and spam-token flagging further sharpens what the tool returns.

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 opening 'Run when you need to know which tokens a wallet holds and how much' gives clear triggering context, and the unverified-flagging note implies when it beats a raw balance check. It never explicitly names an alternative sibling (balance, token_account, find_token) or a when-not condition, so routing still requires some inference.

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