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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so 'does not create, modify, or delete data' is largely redundant. The description does add genuine behavioral context — the exact endpoint and that results are raw, unaggregated snapshots rather than aggregates — but says nothing about billing, rate limits, auth, or pagination behavior with large wallet batches.

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 resource and endpoint, then a safety statement, then the data character — four short sentences with little waste. The final sentence leans slightly toward marketing framing ('for custom analytics') but still carries differentiating information.

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 rich annotations, a fully-documented nested input schema, and an output schema present, the description needn't explain return values. It covers what the tool reads and what kind of data comes back; only cross-sibling routing guidance is missing.

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%, with nested fields (days, limit, sortByAsc/Desc, ownerAddresses, vybeTokenFilter) all documented inline. The description only adds 'the request body lists wallets to read', which restates the schema; no supplementary meaning (e.g. the 10-wallet cap or default 14-day window) is contributed.

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: batch-read token account balance time series for multiple wallets, plus the exact endpoint (POST /v4/wallets/batch/token-accounts-balance-ts). The phrase 'raw balance snapshots ... unaggregated time-series data' implicitly separates it from get-token-balances-batch and get-token-balance-history-batch, but those siblings are never named, so the distinction requires inference.

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 only implied via 'for custom analytics and unaggregated time-series data'; there is no explicit statement of when to pick this over get-token-balances-batch or get-token-balance-history-batch, nor any prerequisite (e.g. wallet count limit, days range) in the prose.

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