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

Beyond the annotations (readOnlyHint, destructiveHint, openWorldHint), the description discloses key behavioral traits: the wallet excludes cash and voucher income, so results understate real revenue for cash-taking operators. It also mentions ordering ('newest first') and what types of transactions are included. This is valuable context that annotations alone do not provide, and there is no contradiction.

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?

The description is three sentences, each earning its place: the first defines the resource and scope, the second gives clear usage guidance, and the third provides a crucial misuse warning and alternative. It is front-loaded with the most important information and contains no fluff.

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 this simple list tool, the description covers purpose, included/excluded transaction types, ordering, use cases, and a critical caveat about revenue understatement. Combined with full schema coverage, a true output schema, and annotations, there are no gaps in contextual information. The description is complete for an agent to select and invoke this tool correctly.

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 input schema already provides 100% coverage for all three parameters (to, from, limit) with clear descriptions and constraints. The description does not add any additional parameter-specific semantics beyond the general 'newest first' ordering, which is already implied by the schema. With complete schema coverage, a score of 3 is appropriate—the schema carries the burden.

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?

Description opens with a precise definition: 'This operator's wallet ledger: gateway earnings, withdrawals and refunds, newest first.' This clearly identifies the resource (wallet ledger), specific transaction types, and ordering, immediately distinguishing it from sibling tools like get_revenue_summary. The verb 'get' is implicit in the tool name and title, and the description adds enough scope to remove ambiguity.

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 explicitly states when to use it ('Use for questions about the wallet, payouts or withdrawals') and when not to use it ('Do NOT use it to answer "how much did I earn"'), naming the alternative tool (get_revenue_summary). This is a model of clear guidance, leaving no doubt about tool selection.

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