mcp-tn-dmv

# @pipeworx/tn-dmv

Tennessee Department of Safety and Homeland Security: the 186 driver service centers with their
per-location service capabilities, plus the state's impaired-driving crash file. Keyless.

## Why Tennessee gets its own pack

This came out of splitting a single multiplexed `us-dmv` tool into one pack per state agency.
Tennessee's grain is a **per-counter capability matrix** — REAL ID, CDL skills test, handgun
permit, vision test — published on the department's own ArcGIS, which has nothing in common
with California's ZIP-level registration snapshot. A union schema across states leaves most
arguments ignored on every call, so Tennessee's arguments are Tennessee's.

## Tools

| Tool | What it returns |
|---|---|
| `tn_dmv_driver_service_centers` | Address, county, hours, phone, coordinates and the 21 service capabilities each location publishes |
| `tn_dmv_impaired_driving_crashes` | Alcohol- and drug-involved injury and fatal crashes for 2022, grouped by age, gender, severity, agency, substance or month, with a mappable sample |

`tn_dmv_driver_service_centers` filters: `city`, `county`, `zip` (prefix), `name`, `service`, `limit`.
`tn_dmv_impaired_driving_crashes` filters: `substance`, `severity`, `age_group`, `gender`,
`agency`, `group_by`, `limit`.

## The distinctive fields

REAL ID, **CDL skills test** (only 4 of 186 locations do it), **handgun permit** (47 locations)
and **vision test** are the filters worth knowing about — they are the questions a plain address
list cannot answer. `office_type` separates the 44 full-service centers from 93 self-service
kiosks, 46 county-clerk partners and 3 express counters, which matters because a kiosk performs
only a handful of the listed services.

## Auth

None. `tnmap.tn.gov` is a public state ArcGIS host.

## Gotchas worth knowing

- **City names run together.** `USER_City` is published as `OakRidge`, `MtJuliet` and similar,
  so `city` is matched after stripping both sides to letters and digits — a caller typing
  "Oak Ridge" gets the Oak Ridge center rather than a not-found.
- **`X` is longitude and `Y` is latitude**, both as attribute columns, so no geometry
  round-trip is needed.
- **Two HTML blob columns had to be excluded.** `USER_Website_Name` and `USER_Website_Services`
  are pre-rendered `<br>`-separated markup that duplicates columns already returned and roughly
  triples the payload; with them included the full-layer fetch failed outright rather than
  merely running slowly. The query names its fields explicitly to leave them behind.
- **The crash layer is person-level, and 2022 only.** `SAFETY/DUICrashesArrestsAgeGender`
  layer 0 holds one row per person involved: ~1,543 person records across ~603 distinct crashes.
  Both numbers are reported (`person_records`, `distinct_crashes`) because quoting the row count
  as a crash count would overstate it by 2.5×. It covers injury and fatal crashes; property-damage-only
  crashes sit outside it. The whole file is calendar year 2022, reported as `as_of`.
- **State troopers are not called "Highway Patrol" in the data.** They appear as
  `THP District 3 - Nashville` and seven other districts, so `agency: "THP"` selects all of
  them; `agency: "HIGHWAY PATROL"` matches nothing.
- **"Unknown" is a real age group**, the agency's own value for records where age was never
  recorded, and it is the largest bucket (386 of 1,543). It is left in rather than silently
  dropped.
- The wider `SAFETY/` ArcGIS folder also carries `DeerCrashes2019to2023` and `I24_CrashHotspots`.
  Both are cartographic multi-layer map services (severity-split display layers, basemap
  boundaries, a weighted-likelihood raster) rather than one queryable table, so they are left
  out; the DUI layer was the one that returned real, aggregatable records.

## Data sources

- [TN SAFETY ArcGIS `DriverServiceCenters/MapServer/0`](https://tnmap.tn.gov/arcgis/rest/services/SAFETY/DriverServiceCenters/MapServer/0)
- [TN SAFETY ArcGIS `DUICrashesArrestsAgeGender/MapServer/0`](https://tnmap.tn.gov/arcgis/rest/services/SAFETY/DUICrashesArrestsAgeGender/MapServer/0)

Both verified live 2026-07-30.

## Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

```json
{
  "mcpServers": {
    "tn-dmv": {
      "url": "https://gateway.pipeworx.io/tn-dmv/mcp"
    }
  }
}
```

Or connect to the full Pipeworx gateway for access to all 1392+ data sources:

```json
{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}
```

## Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English:

```
ask_pipeworx({ question: "your question about Tennessee Driver Services data" })
```

The gateway picks the right tool and fills the arguments automatically.

## More

- [All tools and guides](https://github.com/pipeworx-io/examples)
- [pipeworx.io](https://pipeworx.io)

## License

MIT