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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered and the description only needs to add context. It does add useful scope information (prices are split into subscription and loose device, history extends back to when NuActueel began measuring), but it says nothing about coverage gaps, update frequency, or behavior when the model is unknown. Adequate but thin beyond the annotations.

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 densely packed sentence with no filler, and the primary answer (current minimum price) is front-loaded before the historical range and deltas. Slightly hard to parse due to the parenthetical, but nothing is redundant.

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 carries the burden of explaining return values and does so well — current minimum, historical min/max, and week/month deltas. The single required parameter is fully documented in the schema. Only the lack of routing guidance against sibling price tools leaves a gap.

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?

There is a single parameter at 100% schema description coverage, with the schema already supplying format and examples ("iPhone 16", "Galaxy S25"). The description adds no extra semantics such as matching tolerance or brand spelling rules, so the 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 concretely enumerates what the tool returns for a phone: current minimum price (with subscription and loose device), the all-time low/high since NuActueel started measuring, and the week/month deltas. That makes the resource and the data scope unmistakable. It does not explicitly differentiate itself from nearby siblings such as mobiele_markt or prijsdalers, which is the only thing keeping it from a 5.

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?

There is no statement of when to use this tool versus alternatives, no prerequisites, and no exclusions. An agent must infer from the sibling list alone whether to pick this or prijsdalers/sim_only. Only the implicit 'price history of one device' framing gives any guidance.

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