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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the useful behavioral context that the data is scoped to the authenticated user and that authentication is required, which goes slightly beyond the structured metadata but does not disclose pagination behavior or response characteristics.

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 a single focused sentence that immediately names the operation and its scope, followed by a brief authentication note. Every word contributes meaning, and there is no filler or redundant restatement.

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 simple read-only paginated history tool, the description plus schema and annotations cover the essential invocation context: what it returns conceptually, that it is read-only, and that the caller must be authenticated. The absence of an output schema is acceptable, though a note about the shape of the transaction list could improve completeness.

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 each parameter (page, size, sessionKey) already has a meaningful description in the input schema. The tool description adds no parameter-level detail beyond what the schema provides, so it meets the baseline without adding extra value.

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?

The description clearly states a specific verb and resource: 'Get payment transaction history for the authenticated user.' This distinguishes it from related billing tools like getAccountBalance or listInvoices in broad terms, though it does not explicitly name or contrast those siblings.

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 implies when to use the tool (when payment transaction history is needed for the authenticated user) and states the authentication prerequisite. However, it does not explicitly say when not to use it or mention alternative tools for related financial data, leaving routing partially to inference.

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