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

The annotations already mark the tool as readOnly, idempotent, and non-destructive. The description adds significant behavioral detail on top: it matches items to current offers across named German retailers, weighs prices against travel distance and shopping time, returns a route, per-origin picks with live prices, a worth-it verdict, and a shareable list, and supports multiple travel modes.

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?

Every sentence in the delivery earns its place: it states the core task, disambiguates it, explains matching and routing logic, lists what is returned, and adds a useful corridor-trip extension. The phrasing is front-loaded with the primary purpose and remains dense without fluff.

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?

Given the tool has 9 parameters and a rich output schema, the description still covers the essential completeness: what inputs are expected, how the optimization behaves, which stores/modes are supported, what the output contains, and when `end_location` matters. No critical operational gap remains.

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?

Although the schema already covers all 9 parameters, the description adds important semantics beyond field titles: it explains that `km_cost` and `hour_cost` affect the travel-time/price trade-off, that `end_location` shifts routing from a round trip to a corridor trip, and that `travel_mode` includes the relevant urban modes. This helps an agent select and set parameters meaningfully.

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 uses a specific verb and resource combination: 'Plans the optimal shopping trip for a given list and starting location in Germany.' It further clarifies its purpose by contrasting the answer it provides ('where should I go to buy this list...') with what it does not do ('not what's on offer near me').

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 clearly states when the tool is applicable: given a shopping list and starting location, it determines which stores to visit and whether the trip is worth it. It also gives an explicit usage variant for corridor trips via `end_location`, making the applicable contexts concrete even though no sibling tools are listed.

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