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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description does add real behavioral context the annotations do not: results are restricted to places that have an evaluated report (a coverage filter), and it names the returned fields. It leaves out what happens on zero or ambiguous matches and whether results are capped.

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 with no filler. The lookup capability and its filter come first, with the return contract and downstream purpose second, so an agent can stop reading once it has what it needs.

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 one-parameter lookup with no output schema, the description covers the key facts: input forms, the has-a-report precondition, and exactly which fields come back. Only edge-case behavior (no match, multiple matches, ordering) is absent, which is a minor gap at this complexity.

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 a single parameter at 100% schema coverage, the schema already explains the query accepts a city name or postcode and gives examples. The description adds only the 'five-digit' constraint on the postcode form, which is marginal beyond the schema's own example. Baseline 3 applies.

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?

States a specific verb and resource ('Sucht Orte') plus two qualifying constraints: an existing evaluated test report and lookup by name or five-digit postcode. It also names the return fields and frames itself as the resolver feeding the other tools, which separates it from analysis siblings like get_water_quality or compare_cities. It stops short of naming any sibling explicitly, so differentiation is inferred rather than stated.

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?

'Liefert slug, Name und PLZ für die anderen Tools' implies this is the entry point you call before other tools, which is useful implied guidance. However there is no explicit when-to-use/when-not, no statement about what to do when multiple cities match, and no guidance on when a direct postal-code call is preferable to a name search.

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