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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds ordering ('newest first'), the fact that refunds are included, and an auth requirement ('Needs the user's Cotlet API key with access to this app'), which is genuine context beyond the structured fields.

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 first two sentences are largely redundant, both listing amount, status, payment method, and refund. The valuable content (ordering, refund relationship, auth need) is present but slightly buried behind the repeated field enumeration, so structure is adequate rather than tight.

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 list tool with full schema coverage and annotations, the description covers ordering, returned content, filtering, the refund_charge linkage, and the auth prerequisite. With no output schema, it does describe the return shape. Pagination behavior is the only unstated detail, a minor gap.

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 the schema already documents booking_id and the date bounds. The description's 'Filter by booking or by charge date' restates these without adding format or boundary semantics, so the baseline 3 applies.

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 ('Lists charges from Booking Charges'), enumerates the returned fields (amount, status, payment method, refund), and names the sibling it feeds into ('The charge_id goes to refund_charge'). An agent can distinguish this list tool from refund_charge without opening either 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?

Gives clear usage context: 'Filter by booking or by charge date' tells the agent how to narrow results, and the charge_id-to-refund_charge pointer establishes the workflow relationship with the sibling. It stops short of explicit when-not-to-use guidance, but the routing signal is strong.

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