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

Annotations already cover safety (readOnly, non-destructive, openWorld), yet the description adds the crucial semantic that an empty answer is only an all-clear inside coverage regions, lists which regions those are, discloses AND-combination of line+stop, truncation signalling (truncated/total), and anti-fabrication rules. This is behavioral context far beyond the annotation set.

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?

Dense but well front-loaded: purpose, data-coverage caveat, argument behaviour, format, guide pointer, then anti-fab rules in bold-labeled blocks. It is long, and some of the coverage/guide material is partly delegated, but nearly every sentence carries a distinct operational constraint.

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 and six optional parameters, the description does the heavy lifting: it explains result shape at a high level (two lists, `coverage` values, truncation markers) and points to `get_usage_guide` for field-level detail. The reliance on an external guide for the seven coverage values and message fields is a minor gap but an intentional, disclosed one.

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 coverage is 100%, so the baseline is 3, but the description adds genuine meaning not in the schema: that `line` and `stop` combine with AND, that `area` decides coverage and routes unplaceable reports to `unplaced` rather than suppressing them, and that agents should omit `format`. It mostly reinforces rather than extends the schema, hence 4.

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?

Names a specific verb+resource in the first line ("Aktuelle Störungen, Baustellen und Liniensperrungen im ÖPNV") and immediately distinguishes itself from the sibling tools by stating that connections and departures are unaffected. An agent can tell this apart from departures/connections without opening any schema.

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?

Gives concrete user phrasings that select this tool ("gibt es Störungen", "Ausfälle in X") and a hard filter rule ("Nenne nur Filter, die der Nutzer wirklich nannte"). It does not name a competing sibling tool to route away to, so it is strong context without explicit exclusions.

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