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

No annotations are provided, so the description carries the full behavioral burden and it discloses almost nothing: no auth requirements, no rate limits, no note that limit caps at 100 and offset paginates, no indication of whether matching is case-insensitive or how the Energieträger substring match behaves. The license attribution is the only extra context supplied.

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 sentences, front-loaded with the actionable content, and the second sentence is a legally required data attribution rather than filler. Nothing is wasted, though the facet list is dense in a way that slightly obscures the most important filters.

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?

For a 12-parameter search tool with no annotations and no output schema, the description should say something about pagination, result size limits, sorting defaults, or the shape of results. None of that is present, leaving the agent to discover paging behavior through the schema's defaults alone.

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?

With schema coverage at 50% across 12 parameters, the description usefully maps human terms to the German/short parameter names (Bundesland→land, capacity→min_kw/max_kw, keyword→q), which the schema alone would not convey. However, it leaves sort, fields, limit, offset and einheitentyp entirely to the schema, so it only partially compensates for the coverage gap.

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 verb+resource ('Search/filter MaStR energy units') and enumerates the filter facets, so an agent immediately distinguishes it from mastr_get_unit (single-unit retrieval) and mastr_get_stats (aggregates). It does not explicitly name those siblings, which keeps it just short of 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 when-to-use guidance and no stated alternatives — nothing tells the agent to prefer mastr_get_unit once it has an ID, or when a keyword search is the right entry point versus a filtered one. Usage is only implicitly inferable from the tool name.

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