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

Annotations already cover readOnly, idempotent, non-destructive and closed-world behavior, so the description's added value is the freshness contract: hourly updates, per-report quelle/quelle_url/lizenz, and the meaning of datenstand_warnung=true (data older than 3 hours). That is genuine behavioral context an agent cannot get from the annotations or schema.

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?

A single dense paragraph, front-loaded with scope, followed by filters, then return fields and the freshness flag. Every clause carries information; there is no filler.

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 read-only, no-output-schema query tool, this covers scope, sources, filter vocabulary and result-shape hints (source, URL, license, staleness flag). The remaining gaps are the undocumented max cap and the lack of expected format for bezirk and suchtext.

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 0%, so the description must carry the parameter burden. It explains art values (oepnv, aufzug, strasse — omitting 'alle' from the enum) and gives concrete linie examples (U8, S41, M10), but bezirk and suchtext get only a name, and the max parameter is not mentioned at all.

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 concrete resource (current Berlin traffic reports, updated hourly) and enumerates the covered modes and sources: S-Bahn, U-Bahn, Tram, Bus, Regionalverkehr (VBB), elevators out of service, and road construction/closures (VIZ Berlin). This is far more specific than the siblings (berlin_heute, termine_suchen, orte_suchen), so an agent can tell immediately what domain this serves.

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?

Usage is implied by the described content and by the filter list (art, linie, bezirk, suchtext), so an agent knows how to narrow results. However, there is no explicit statement of when to prefer this over siblings like berlin_heute, nor any exclusion or prerequisite guidance.

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