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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful scope context (192 apps, requirements plus cheapest matching plans), but says nothing about whether prices are live or cached, how 'cheapest' is determined, or how results are shaped.

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?

A single front-loaded sentence with no filler, and the app examples and 192-app count earn their place by signaling breadth. It is a noun phrase rather than a full sentence, which slightly weakens the opening.

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 no output schema, the description must carry the return-value burden and only partially does so: it promises requirements and cheapest plans but omits whether providers, prices, or plan links are included. For a read-only lookup tool with annotations covering safety, this is adequate but incomplete.

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 all three parameters are already documented in the schema, and the app examples in the description largely duplicate the schema's own examples. Nothing is added about how location interacts with the cheapest-plan selection or how max_usd_month filters results, so 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?

The description names the resource (documented requirements for a self-hosted app/game server) and the output (cheapest plans that meet them), with a concrete example list and scale (192 apps). It distinguishes itself implicitly from price-first siblings like ask_vps_prices and search_vps_plans by being app-driven, but never names or contrasts them.

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?

Usage is only implied: the agent infers it should call this when it has an app in mind and wants matching hosting. There is no explicit when-to-use, when-not-to-use, or routing to alternatives such as advise_vps_choice or current_vps_offers, which is a real gap given four sibling tools in the same space.

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