ViaFrei

get_driving_rules

Read-onlyIdempotent

Returns the German road rules a visitor needs: low-emission zones (Umweltzone) and the Feinstaubplakette, speed limits (advisory 130), winter tyres, alcohol, the Sunday lorry ban, tolls, Rettungsgasse, what must be in the car, electric cars. Use when someone drives through Germany or asks whether they may enter a city or street. Do NOT use for live traffic or closures: check_autobahn_traffic; to FIND a charger: find_charging_station. city narrows to its zone; place or lat+lon checks a point against the published zone boundaries. Sourced, dated; show the attribution. Not legal advice.

Input Schema

Name	Required	Description	Default
`lat`	No	Latitude (WGS 84) of the point to check against the zone boundaries. Use with lon; otherwise use place.
`lon`	No	Longitude (WGS 84) of the point to check against the zone boundaries. Use with lat; otherwise use place.
`city`	No	City the question is about, e.g. "Stuttgart", "München", "Munich". Narrows "lez" to that city's zone and adds the per-city caveat for "ev". Other topics are nationwide. Omit when the question is not about one city.
`place`	No	A street address, district, station or other point ("Alexanderplatz, Berlin", "Kölner Dom") to check against the published low-emission-zone boundaries: inside, outside with the distance, or unknown. Given with lat+lon, lat+lon is checked and the place is its label, unless the two lie further apart than 10 km plus the town's extent.
`topic`	No	Which rule to answer. "lez" = low-emission zone and Feinstaubplakette, "speed" = speed limits including the Autobahn advisory 130, "winter" = winter-tyre duty, "alcohol" = alcohol and drugs, "toll" = car and lorry toll, "truck_ban" = Sunday and holiday lorry ban, "equipment" = what the law requires in the car, "emergency" = 112/110, rescue lane, breakdown, crash, "ev" = electric car (E-Kennzeichen, charging payment, plugs). Omit for a one-line overview of all nine; with place or lat+lon, omitted means "lez".
`language`	No	Set this on every call to the language the person is writing in: "en" if they wrote English, "de" if they wrote German. Do not leave it out: it defaults to German ("de"), which is only the fallback when the language is genuinely unclear, so an English question sent without it is answered in German — a wrong answer. Place names, station names and road numbers are never translated in either language; in English the German term is kept in parentheses so the person recognises it on signs and in local apps.	de

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedNov 2, 2026

changedInput schema / properties / place / description

Previous value: -"A street address, district, station or other point (\"Alexanderplatz, Berlin\", \"Kölner Dom\") to check against the published low-emission-zone boundaries: inside, outside with the distance, or unknown. Give either place OR lat+lon, never both."New value: +"A street address, district, station or other point (\"Alexanderplatz, Berlin\", \"Kölner Dom\") to check against the published low-emission-zone boundaries: inside, outside with the distance, or unknown. Given with lat+lon, lat+lon is checked and the place is its label, unless the two lie further apart than 10 km plus the town's extent."

Changed4 schema fields changedOct 19, 2026

addedInput schema / properties / lat

Added value: +{
+  "description": "Latitude (WGS 84) of the point to check against the zone boundaries. Use with lon; otherwise use place.",
+  "maximum": 90,
+  "minimum": -90,
+  "type": "number"
+}

addedInput schema / properties / lon

Added value: +{
+  "description": "Longitude (WGS 84) of the point to check against the zone boundaries. Use with lat; otherwise use place.",
+  "maximum": 180,
+  "minimum": -180,
+  "type": "number"
+}

addedInput schema / properties / place

Added value: +{
+  "description": "A street address, district, station or other point (\"Alexanderplatz, Berlin\", \"Kölner Dom\") to check against the published low-emission-zone boundaries: inside, outside with the distance, or unknown. Give either place OR lat+lon, never both.",
+  "maxLength": 120,
+  "minLength": 1,
+  "type": "string"
+}

changedInput schema / properties / topic / description

Previous value: -"Which rule to answer. \"lez\" = low-emission zone and Feinstaubplakette, \"speed\" = speed limits including the Autobahn advisory 130, \"winter\" = winter-tyre duty, \"alcohol\" = alcohol and drugs, \"toll\" = car and lorry toll, \"truck_ban\" = Sunday and holiday lorry ban, \"equipment\" = what the law requires in the car, \"emergency\" = 112/110, rescue lane, breakdown, crash, \"ev\" = electric car (E-Kennzeichen, charging payment, plugs). Omit for a one-line overview of all nine."New value: +"Which rule to answer. \"lez\" = low-emission zone and Feinstaubplakette, \"speed\" = speed limits including the Autobahn advisory 130, \"winter\" = winter-tyre duty, \"alcohol\" = alcohol and drugs, \"toll\" = car and lorry toll, \"truck_ban\" = Sunday and holiday lorry ban, \"equipment\" = what the law requires in the car, \"emergency\" = 112/110, rescue lane, breakdown, crash, \"ev\" = electric car (E-Kennzeichen, charging payment, plugs). Omit for a one-line overview of all nine; with place or lat+lon, omitted means \"lez\"."

First observedOct 15, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnlyHint/idempotentHint/openWorldHint=false, so safety is covered. The description adds real context beyond that: results are 'sourced, dated', attribution must be shown, and it disclaims 'not legal advice' — a disclosure an agent needs to relay. It does not describe result completeness or how boundaries are versioned, keeping it below a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the resource and the use/don't-use routing before the parameter notes, which is the right order. The nine-item enumeration of topics duplicates the `topic` enum description verbatim in places, a small redundancy that costs some density, but no sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description still covers scope, alternatives, parameter routing, sourcing/attribution and the legal disclaimer — enough to call it correctly. It never states what the default no-parameter call returns beyond the schema note, which is the one remaining gap for a 6-param, all-optional tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description goes slightly beyond by summarizing the interplay between parameters ('city narrows to its zone; place or lat+lon checks a point against the published zone boundaries'), which lets an agent choose the right selector without reading all six schema descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Returns the German road rules a visitor needs') and enumerates the covered domains: Umweltzone/Feinstaubplakette, speed limits, winter tyres, alcohol, lorry ban, tolls, Rettungsgasse, equipment, EVs. An agent can immediately distinguish this from check_autobahn_traffic, find_charging_station and check_road_status.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit positive trigger ('Use when someone drives through Germany or asks whether they may enter a city or street') plus explicit exclusions naming the alternative tools for live traffic/closures and charger lookup. Both when-to-use and when-not-to-use are stated, with the sibling named for each exception.

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

All ViaFrei tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?