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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true, so safety is covered. The description still adds real behavioral context: it discloses what is returned (source-provided facts, statuses, breakdown labels, coverage notes) and explicitly notes it 'does not prescribe seller actions' and requires pagination to completion. It stops short of describing auth or rate-limit behavior, keeping it at 4.

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 and source are front-loaded, then mode selection, then return semantics. It is dense and somewhat long, but nearly every clause carries distinct information (source, modes, pagination, return shape, action stance) rather than restating the name.

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 an output schema present, the description needn't enumerate return values, and it still summarizes them. Combined with the mode-selection guidance and pagination-completion rule, an agent has everything needed to call a 14-parameter, zero-required 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?

Schema coverage is 100%, so the baseline would be 3. The description goes beyond the schema by explaining how the key filter parameters select mutually exclusive modes (financial_event_group_id vs order_id vs date-window) and how transaction_status=RELEASED interacts with the group mode, adding meaning not captured in the raw field descriptions.

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 ('Get live Amazon Payments / Transaction View-style transactions') and pins the upstream source (SP-API Finances v2024-06-19). This distinguishes it from neighbors like get_financial_events, get_settlement_economics, and get_reimbursements without needing to open any schema.

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?

Explicitly routes the agent across three modes: financial_event_group_id + transaction_status=RELEASED for finalized reconciliation, date-window for pre-settlement recent rows, and order_id for a single order. It also states the condition that makes a financial-event-group result 'complete' (paginate until has_more is false), which is actionable usage guidance.

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