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

With no annotations, the description carries the burden and does well: it discloses the return value (a wa.me URL), what the prefilled message contains, and the critical domain fact that booking happens off-platform on WhatsApp. It stops short of stating that no server-side state is created or whether the link is stable/reusable, which would matter for repeated calls.

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?

Four sentences ordered as what-it-does, what-it-returns, when-to-use, and business context. No repetition of the name or title, and every sentence carries information the agent needs.

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?

No output schema exists, and the description compensates by describing the return value explicitly. All five parameters are documented in-schema and the one required field (slug) is unambiguous, so nothing needed for a correct call is missing.

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 baseline is 3, but the description adds real meaning by explaining that dates, party size, and notes are all optional inputs that get folded into the prefilled message. That tells the agent why to supply them and that omitting them is safe, beyond the schema's per-field notes.

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 ("Generate a WhatsApp inquiry link for a Fursat home") and immediately names the concrete artifact produced ("a wa.me URL"). The phrase "after seeing it in search results" implicitly separates it from search_listings/get_listing, so an agent can place it in the flow without opening another 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 a clear triggering condition: "Use this when a traveler wants to actually book or inquire about a specific home after seeing it in search results." It also rules out an expectation ("there is no online checkout"), but never explicitly names get_listing or search_listings as the prior-step alternatives.

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