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

With no annotations, the description carries the full burden, and it discloses the key behavior: it returns a wa.me URL, the message is prefilled with listing identity and optional dates/party size/notes, and booking actually happens on WhatsApp rather than through an online checkout. It does not cover edge behavior like invalid slugs or error handling, but this is sufficient for a simple link-generation tool.

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?

Three focused sentences with no wasted words. The output and purpose are front-loaded, and the note about bookings happening on WhatsApp is the kind of high-signal context that 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?

For a simple link-generation tool, the description covers what it does, when to use it, what is returned, and how the broader booking flow works. It lacks explicit error/edge-case information or direct comparison with sibling tools, but neither is essential for correct invocation.

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 baseline is 3, but the description adds functional context by explaining that the optional parameters (dates, party size, notes) become part of the prefilled WhatsApp message. This helps the agent understand how the parameters are used together, which the schema alone does not convey.

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 opens with a specific verb and resource: 'Generate a WhatsApp inquiry link for a Fursat home.' It clearly states the output (wa.me URL with prefilled message) and distinguishes this tool from the sibling lookup tools by making its booking/inquiry purpose explicit.

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?

It explicitly says to use this when a traveler wants to book or inquire about a specific home after seeing it in search results. This gives clear context and implies search_listings is the upstream step. It stops short of naming the alternatives or stating when not to use it, so it misses the top score.

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