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

Annotations only say readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description adds substantial context beyond that: it sends an email to an external party ('reaches other people'), requires confirmation with the user before each call, needs a Cotlet API key with app access, and notes the default confirmation behavior can be toggled off.

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 purpose and effect, then usage constraints. Slightly repetitive: the confirmation requirement is stated twice ('By default you confirm each call' and 'confirm with the user before each call'), which costs a little efficiency but does not obscure meaning.

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 one-parameter action tool with no output schema, the description covers side effects, timing conditions, human confirmation, and auth requirements. An agent has everything needed to decide whether and how to invoke it.

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?

With a single required parameter at 100% schema description coverage, the schema already documents booking_ref and its source ('from search_bookings or list_new_bookings'). The description adds no format or syntax detail beyond this, 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+resource ('Report Payment Issue on a booking') and immediately clarifies the actual effect: triggering Hostelworld's automatic payment request email to the guest. This distinguishes it from adjacent hostelworld tools like send_chat_message or mark_no_show.

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?

Explicit when-to-use condition: 'Use it only when the payment deadline in your policy has expired and your terms were visible at booking,' plus a follow-up path (request cancellation after 24 hours). The preconditions and sequencing are spelled out rather than left to inference.

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