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

Annotations already declare a readonly, idempotent, non-destructive, closed-world operation, so the safety bar is lower. The description still adds high-value behavior beyond them: the tool 'opens nothing by itself' and returns a procedure rather than data, plus the fact that Hostfully exposes an official REST API (Open API v3) but no official MCP server, explaining why browser automation is required.

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?

Purpose and the critical 'opens nothing by itself' caveat are reasonably front-loaded, but the final sentence is a provenance note (API version, check date) that does little to help an agent invoke the tool, and the run-on construction of the first sentence blurs the data-vs-instructions distinction.

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?

With zero parameters, no output schema, and clear annotations, the definition covers what the agent most needs: what comes back (a walkthrough) and what to do next (cotlet_browser_* tools in the Hostfully Cloud Browser). It stops short of stating prerequisites such as the Hostfully app being connected or what the step-by-step payload looks like.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. No misleading parameter claims are made.

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 names a concrete resource ('reservations in the user's own Hostfully account') and, crucially, discloses that the tool does not itself return data but a step-by-step procedure ('screens, buttons, fields'). The one weakness is tension between the name/title ('List reservations') and the actual return of instructions, which could momentarily mislead an agent expecting a data listing.

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 gives a clear follow-on path: 'then do it with the cotlet_browser_* tools in the user's Hostfully Cloud Browser', which is real usage guidance. However, it offers no explicit when-not or comparison against siblings such as hostfully_get_reservation or hostfully_list_properties, so the agent must infer which tool to reach for.

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