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

Annotations already declare readOnlyHint, idempotentHint and a closed world, so the safety profile is covered. The description earns credit for going beyond that by disclosing the status vocabulary (boven/op_koers/onder) and the edge case that measurement is manual and yields 'nog_niet_ingevuld' when no value was entered this period — real behavioral context absent from 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?

Two short sentences, front-loaded with the resource and its fields before the measurement caveat. The phrasing is telegraphic ('Meting handmatig: met eenheid') and slightly fragmented, but every clause carries information.

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 parameters and no output schema, the description has to convey the return shape, and it does name the fields returned plus the enum-like status values and the empty-period sentinel. What it omits — ordering, whether inactive goals are excluded, how 'deze periode' is determined — is minor for a zero-argument list 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?

The tool takes zero parameters, so there is no parameter semantics to explain and the baseline of 4 applies. The description does not waste space restating a schema that is empty.

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 a specific resource and scope: 'Actieve KPI-doelen' (active KPI targets), and lists what each record carries (actueel, doel, verschil, stand). An agent can tell this is a read of KPI goal objects, but no sibling (e.g. crm_pijplijn, crm_deals) is named as the contrasting alternative, so differentiation is left implicit.

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 explicit when-to-use statement, no negative case, and no reference to an alternative tool. The agent must infer from the read-only nature and title that this is the KPI reporting endpoint rather than a filterable search tool.

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