Atlas MCP Server

@urbankitstudio/mcp-atlas

Query the parcel ArcGIS REST endpoints of 515 counties across 51 US states (50 states plus DC), 509 endpoints total, for owner, APN and address lookup via the Model Context Protocol (MCP).

An MCP server that gives AI assistants direct access to UrbanKit Studio's atlas of manually verified county parcel GIS services. Ask Claude or Cursor to find the ArcGIS REST endpoint for any covered county, get the exact owner-search query URL, and look up parcel data — without needing to know anything about ArcGIS REST API conventions.

Coverage: 515 counties across 51 US states (50 states plus DC), 509 endpoints, 509 of them live (atlas 0.7.2). 481 of the counties have an endpoint; for the other 34 the atlas records why not (see "A county we cannot serve" below).

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Quick start

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "mcp-atlas": {
      "command": "npx",
      "args": ["-y", "@urbankitstudio/mcp-atlas"]
    }
  }
}

Cursor

Add to .cursor/mcp.json in your project root (or ~/.cursor/mcp.json globally):

{
  "mcpServers": {
    "mcp-atlas": {
      "command": "npx",
      "args": ["-y", "@urbankitstudio/mcp-atlas"]
    }
  }
}

Install globally (optional)

npm install -g @urbankitstudio/mcp-atlas

Then use mcp-atlas as the command instead of npx -y @urbankitstudio/mcp-atlas.

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Tools

The first four tools are one county pipeline, and what separates them is how precisely you can already name the county. The fifth, get_city_datasets, is separate: it answers about a city, not a county.

find_county and get_parcel_endpoint return the same per-county record. They differ in how you address the county: find_county accepts an uncertain reference and may come back with several candidates, get_parcel_endpoint takes an exact pair and answers about one. If you already know the county, skip find_county.

This server never executes a query and returns no parcel records. It tells you the URL to fetch; fetching it is yours to do.

A county we cannot serve

find_county, get_parcel_endpoint and build_owner_query give one answer for a county with no endpoint to hand back, the same text the hosted UrbanKit MCP server, its REST API and the uks CLI give. It comes from coverageAnswer() in @urbankitstudio/atlas 0.6.38:

• The atlas has no record (a misspelling lands here too): "This county is not in the UrbanKit atlas", with a prompt to check the spelling first.
• The atlas records the county and it publishes nothing we can serve (Shelby TN, whose terms bar public display; Columbia PA, whose layer has parcel numbers only): the reason in one sentence, the date we last checked, the date of the next check when one is set, the county's own office and, where the county sells the data, its own product.

Both end with a free request for the county: a ready body for request_county on the hosted MCP server or POST https://urbankitstudio.com/api/atlas/request. Requesting does not promise we add the county. list_counties still lists only the counties we serve.

list_counties

Browse coverage. Answers "is this county covered?" and "what can I search there?" — one line per county, with no endpoint URLs or field names.

Example prompt: "List all covered counties in Illinois"

Example output:

ST | County               | Slug                     | Coverage
--------------------------------------------------------------------
IL | Kane                 | kane-county              | owner+APN
IL | Cook                 | cook-county              | APN only
IL | DuPage               | dupage-county            | owner+APN
...

What each Coverage label promises:

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find_county

Resolves a reference you cannot state exactly. Fuzzy-matches a partial or misspelled name, a "County State" phrase, or a 5-digit FIPS code against every covered county, and names each county it matched so an ambiguous reference comes back as a list to choose from. Each match carries that county's record: endpoint URLs, searchable field names, owner field, sample query, license.

Example prompt: "Find the parcel endpoint for Kane County Illinois"

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get_parcel_endpoint

The default lookup once the county is known. Returns the full ArcGIS REST URL, layer index, searchable fields, owner field (or why no owner query is offered), the county's Scope: predicate when the layer is shared statewide or regionally, a generic sample ?where=…&f=json query and the UrbanKit deep-link for one county. For a named owner, use build_owner_query rather than editing the sample query by hand. On a layer that flags confidential owners it prints the Confidential flag: exclusion to AND into any query of your own, and prints its own sample owner query in place of the atlas's, so the one sample shown carries this server's clauses.

Example prompt: "Give me the ArcGIS REST endpoint for Cook County Illinois"

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build_owner_query

The only tool that searches for a named owner. Fills a person or company name into the county's verified owner/taxpayer field as UPPER(field) LIKE UPPER('%NAME%'), a case-insensitive partial match, and returns a URL you can fetch or open. On a shared statewide or regional layer (Connecticut's regional composites, for example) the county's scope predicate is ANDed in front, as (scope) AND UPPER(field) LIKE …, so only that county's rows come back.

Some layers publish an owner whose record must not be shown, and flag it in a column beside the owner: Texas Tax Code §25.025 lets peace officers, judges, family-violence victims and others keep their home address confidential, and Harris and Collin mark those accounts (Ector carries a forward guess). On such a layer the query excludes flagged rows, as (…) AND UPPER(CAST(flag AS VARCHAR(255))) NOT LIKE '%Y%', a contains test for every flag value (Harris packs one flag per ownership slot, YNNNNNNNNN). SQL UPPER matches the atlas's uppercase rule on ASCII only, so each of the 17 non-ASCII characters whose uppercase holds an ASCII letter (ß, a dotless i, the fi ligatures, ẙ and the like) gets a clause of its own when it shares a letter with a value: CAST(flag AS VARCHAR(255)) NOT LIKE '%ẙ%' drops a cell holding one. Those clauses still lean on the county's database (an UPPER that maps a-z to A-Z, a LIKE that reads past an embedded NUL, no cell cut off at the 255-character cast, one encoding for cell and literal), so the query ends with a clause that does not: flag IN (…), the exact raw cells the atlas lists as safe (confidentialFlag.safeValues: Harris's blank and N runs, each 10 characters; Collin F; Ector 0). A row stays only when the database itself says its cell equals one of those values, under its own comparison rules, so a NUL, a cut-off cell or a value nobody has reviewed drops out. A backend that ignores trailing spaces or case also keeps the same safe value padded differently or in another case; none of those holds a flag value. A flag without safe values, or with one that holds a marker, offers no owner query. On 2026-10-26 the IN clause kept exactly the rows the contains clauses keep on all three layers (Harris 1,541,671, Collin 435,783, Ector 77,042), and those lists were each layer's complete distinct values. A value longer than one character is a contains test too, which deliberately excludes more than the atlas's trimmed-equality rule: for SEALED, the cells SEALED and UNSEALED drop out as well. The cast lets one form serve a text or an integer column, and UPPER on both sides compares the flag without regard to case. A row with no flag recorded (NULL) counts as flagged and drops out. The flag column comes back with each row; never show or pass on a row whose flag is set.

An endpoint is refused, with the reason, rather than handed a query that finds nothing, hangs, or serves confidential owners:

• a reviewed record says the county publishes no usable owner name;
• the layer serves no attribute search at all (query it by location instead);
• the owner column is not searchable by name (use a parcel-id or location query);
• the layer carries a confidential-owner flag that is present but incomplete (no column, no values, or a value that is not ASCII letters and digits only), so no exclusion can be built.

A refusal that points to a location, parcel-id or address read also prints the layer's Confidential flag: line, and on a flagged layer its advice follows the flag. With a well-formed flag, the read must request the flag column in outFields and keep a row only when its flag cell is exactly one of the safe values and contains no flag value, dropping every other row (a missing or NULL cell included); a layer with no attribute search takes no where clause, so that filtering is the reader's, and its Confidential flag: line gives that row rule in place of "AND this into every query". With an incomplete flag, the refusal advises no read at all: do not read owner fields on that layer. find_county and get_parcel_endpoint carry the same advice in their Confidential flag: line, and their Owner line says why no owner query is offered.

Every free-text argument of every tool refuses control characters (CR, LF, TAB, NUL and the rest of U+0000 to U+001F, U+007F, and the C1 controls U+0080 to U+009F), the line and paragraph separators U+2028 and U+2029, and the whole Unicode Bidi_Control set (U+061C, U+200E, U+200F, U+202A to U+202E and U+2066 to U+2069), so an argument echoed into an answer cannot start a line of its own there or reorder how the text around it displays. Other invisible characters, such as U+200B, U+FEFF and the soft hyphen U+00AD, still pass. A validation error on a tool argument never repeats the value it refused (the MCP SDK's own error for an unknown tool name does quote that name).

Example prompt: "Build an ArcGIS query for properties owned by 'Smith' in Kane County IL"

Example output:

County:       Kane, Illinois
Owner field:  TaxName
WHERE clause: UPPER(TaxName) LIKE UPPER('%SMITH%')

Query URL:
https://gistech.countyofkane.org/arcgis/rest/services/KanePINList/MapServer/0/query
  ?where=UPPER(TaxName)%20LIKE%20UPPER('%25SMITH%25')
  &outFields=PIN,TaxName,SiteAddress,SiteCity,MailingAddress
  &returnGeometry=false&f=json&resultRecordCount=25

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get_city_datasets

City code-violation, building-permit and zoning-case datasets. Give a city slug (fort-worth) or name (Fort Worth, Fort Worth, TX), optionally a kind and a street line, and it returns each verified dataset for that city: the endpoint and provider (Socrata, ArcGIS, CKAN or CARTO), the column the address is matched on, the date field, any filter that is part of the dataset's definition, coverage and freshness notes, and, when you pass a street, a ready query_url to run against the city's own server. Omit city to list every covered city.

• A name shared by two cities comes back as found: false, ambiguous: true with the candidates; repeat with state. A city outside the registry comes back as found: false with the covered cities in its state, or in its county when the reference names one.
• query_url is null for a point lookup (a polygon docket or a current-zoning map); the dataset's query_template then carries the request with a {LON},{LAT} placeholder to fill in.
• Scope is the city's limits, not the county. These tables hold no owner data: for a parcel's owner, use the county tools above.
• Like the county tools, this one fetches nothing. It answers from the atlas package and hands you URLs to run yourself. Socrata throttles anonymous callers, so send your own X-App-Token header for volume.
• It is the same tool the hosted UrbanKit MCP serves, with the same advertised inputs and response keys. The stdio server holds arguments to that schema strictly: kind must be violations, permits or zoning in lower case.

Example prompt: "Where do I pull open building permits for 600 Commerce St, Dallas?"

Example output (abridged):

{
  "found": true,
  "city": { "slug": "dallas", "name": "Dallas", "state_abbrev": "TX", "county_slug": "dallas-county" },
  "street": "600 Commerce St",
  "datasets": [
    {
      "kind": "permits",
      "provider": "socrata",
      "endpoint": "https://www.dallasopendata.com/resource/e7gq-4sah.json",
      "address_field": "street_address",
      "street_used": "600 Commerce St",
      "query_url": "https://www.dallasopendata.com/resource/e7gq-4sah.json?$where=upper(street_address)%20like%20upper('%25600%20Commerce%20St%25')&$limit=30"
    }
  ]
}

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Example conversation

User: I'm doing due diligence on properties in Kane County, Illinois. Can you find all parcels owned by "Blackstone"?

Claude (using mcp-atlas):

1. Calls get_parcel_endpoint → gets the gistech.countyofkane.org URL and confirms the owner field is TaxName
2. Calls build_owner_query with owner_name=Blackstone → returns a ready fetch URL
3. Optionally fetches the URL and formats the parcel results

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Atlas coverage

The atlas is maintained by UrbanKit Studio. All endpoints are manually verified. Counties with an owner/taxpayer field support full name-based lookups; PIN-only counties support APN/parcel-number queries.

Full coverage map: https://urbankitstudio.com/parcel-atlas

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Data

Atlas data is embedded in the package (no network calls at startup). The underlying @urbankitstudio/atlas SDK is also published separately for programmatic use.

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What Socket flags, and how much of it is ours

Socket's supply-chain scanner rates this package in the mid-70s. Clicking through shows a long alert list. Each alert, checked rather than waved away:

Vulnerability and license both come back at 100, quality at 99. The number the badge shows is the supply-chain sub-score, and its single largest deduction is download count, a popularity measure wearing a security badge's clothes. Judge the list above, not the digit.

The four access alerts are what let the server read its own config and talk to a client over stdio, nothing more. It still never executes a query or returns a parcel record.

License

MIT — © 2026 UrbanKit Studio LLC