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

In the absence of annotations, the description carries the full burden. It discloses that the tool returns a wa.me URL with a prefilled message, and explains that bookings are done on WhatsApp. This gives the agent good understanding of the behavior without revealing any hidden side effects. No contradictions.

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 two sentences long with no wasted words. The first sentence states the action and result; the second provides usage context. Every part earns its place.

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?

Given there is no output schema, the description fully explains the return value (wa.me URL). It covers all parameter roles and provides a clear use case. The tool is simple, and the description leaves no obvious gaps.

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 descriptions for all 5 parameters (100% coverage). The description adds value by explaining that the prefilled message includes 'the listing and (optionally) the guest's dates, party size, and notes', and adds a character limit hint for 'notes'. This goes beyond the schema.

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 the verb ('generate') and resource ('WhatsApp inquiry link'), and specifies the return type ('wa.me URL'). It distinguishes itself from siblings 'get_listing' and 'search_listings' by focusing on generating a link for booking/inquiry rather than retrieving information.

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 the tool: 'when a traveler wants to actually book or inquire about a specific home after seeing it in search results.' It also provides important context that bookings happen on WhatsApp. However, it doesn't explicitly state when not to use it or provide alternatives, so it's not a 5.

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