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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, and the description confirms the read-only nature. Its real added value is disclosing the access model, that is, 0.02 USDC via x402 or an API key, and that x402 clients auto-pay while API-key clients pay nothing, which is a behavior an agent must know. It says nothing about rate limits, what a missing snapshot for a date returns, or how large the history window can be.

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 definition, then a usage sentence, then a short bracketed access note; nothing is buried. The second sentence is slightly redundant, since 'or wants historical on-chain portfolio data for a date range' restates the first clause.

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 read-only, open-world query tool with a fully described input schema and no output schema, the definition covers what is queried, when to use it, and the payment or auth paths an agent must know. The remaining gap is that pass-through objects (filters, order_by) and the response shape (how many entries a page contains) are left entirely to other sources.

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 one of the 7 parameters is documented in the schema already, which sets the baseline at 3. The description only gestures at the date range and wallet categories and adds no syntax or behavior for chains, filters, order_by or pagination, so it does no work 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: historical snapshots of smart-money wallet holdings on specific dates, returning per-wallet-category USD values. The word 'historical' implicitly separates it from the sibling get_smart_money_holdings, but that contrast is never made explicit even though both tools appear in the sibling list.

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?

Gives a clear trigger: 'when the user wants to see how smart-money positioning has changed over time' or wants on-chain portfolio data for a date range. It falls short of a 5 because it never names the current-snapshot sibling as the alternative, nor does it state when not to use it.

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