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

The annotations already declare this as a read-only, closed-world lookup, and the description adds meaningful behavioral context: results are refreshed every morning and include computed averages with promotional pricing and estimated inflation effects. It does not contradict the annotations and discloses enough about the data's nature for an agent to use it confidently.

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?

The description is front-loaded with the core purpose and then enumerates the returned pricing dimensions efficiently. It is a single dense sentence followed by a short freshness note, with little waste, though the long enumeration makes it slightly heavier than ideal.

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 explain return values, and it does so well: current monthly price, term average including promotional and one-time costs, inflation-adjusted average, network, and offer link. It lacks minor details such as result count or exact sorting beyond 'cheapest', but is otherwise complete for this lookup tool.

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 the input schema already fully documents bundel, netwerk, and looptijd. The description only indirectly echoes the data-bundle parameter with 'met minstens zoveel data' and does not add meaning beyond the schema, making the baseline 3 appropriate.

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 clearly states the specific resource and comparison: cheapest SIM-only plans per provider with a minimum data bundle. It is not a tautology and explains exactly what is being compared, though it does not explicitly differentiate this tool from nearby siblings like mobiele_markt or toestelprijs.

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?

The intended use is strongly implied by the purpose statement: compare SIM-only subscriptions by data bundle, network, and contract length. However, the description gives no explicit when-to-use guidance, no exclusions, and does not name alternatives such as mobiele_markt for broader market information.

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