ep_online_energielabel

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

Annotations indicate readOnlyHint=true and openWorldHint=true, which the description aligns with by stating it is a lookup operation. The description adds useful behavioral context: it lists the specific data returned (energy class, dates, building type, BAG ids, energy indicators) and mentions the API key requirement. No contradictions with 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?

The description is extremely concise, consisting of two sentences that are front-loaded with the tool's purpose and return values. Every sentence provides essential information without redundancy or 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's complexity (7 parameters, no output schema), the description covers the key aspects: purpose, return data, query methods, and API key requirement. It does not detail all possible response fields, but the listed categories are sufficient for an agent to understand what to expect. The lack of an output schema is somewhat mitigated by the clear description.

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 input schema has 86% description coverage, which is high. The description gives an overview of query methods but does not add significant detail beyond the schema's parameter descriptions. For example, it notes that postcode requires huisnummer unless bagId is given, which is already present in the schema. Therefore, the description adds marginal value over the schema.

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 tool's purpose: looking up registered energy labels for Dutch addresses from EP-Online. It specifies what is returned (energy class, dates, building type, BAG ids, energy indicators) and the two query methods (postcode+huisnummer or BAG id). This distinguishes it from sibling tools that focus on other Dutch address or government data.

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 description provides clear guidance on when to use the tool (to retrieve energy label information) and how to query (by postcode+huisnummer or BAG id). It also notes the required API key. However, it does not explicitly state when not to use it or suggest alternatives among the many sibling tools, though the specificity of the tool makes this less critical.

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