@cyanheads/openstreetmap-mcp-server

v0.4.1

Published

6 hours ago

Geocode, reverse geocode, and run Overpass spatial queries on OpenStreetMap data via MCP. STDIO or Streamable HTTP.

Public Hosted Server: https://openstreetmap.caseyjhand.com/mcp

Tools

6 tools for geocoding and spatial queries against OpenStreetMap data:

| Tool | Description | |:---|:---| | openstreetmap_search_places | Convert a place name or address to geographic coordinates and structured place data | | openstreetmap_reverse_geocode | Convert latitude/longitude coordinates to the nearest address or place name | | openstreetmap_lookup_objects | Fetch address details for one or more known OSM objects by their IDs | | openstreetmap_query_nearby | Find OSM features within a radius around a geographic point | | openstreetmap_query_bbox | Find OSM features within a rectangular bounding box | | openstreetmap_query_raw | Execute a raw Overpass QL query for advanced spatial operations |

`openstreetmap_search_places`

Convert a place name or address to geographic coordinates via Nominatim/OpenStreetMap.

Two input modes: free-form query string (e.g., "Space Needle Seattle") or structured address fields (street, city, state, country, postal code) — mutually exclusive
Country filtering via ISO 3166-1 alpha-2 codes (countrycodes)
Data layer filtering: address, poi, railway, natural, manmade
Feature type restriction: country, state, city, settlement
Optional extra OSM tags on the matched object — contact and metadata (phone, website, opening_hours, wikidata) plus physical attributes (surface, sac_scale, ele, access)
Preferred language override via BCP 47 code
Returns results ordered by Nominatim importance score (global prominence)
Results include coordinates, structured address, bounding box, OSM type/ID for chaining into openstreetmap_lookup_objects
Matches on name and address relevance, never on an OSM attribute tag — extratags decorates the matched object and cannot select one, so an absent tag describes that object rather than OpenStreetMap. Selecting or enumerating by tag is Overpass-only (openstreetmap_query_nearby, openstreetmap_query_bbox, openstreetmap_query_raw)

`openstreetmap_reverse_geocode`

Convert latitude/longitude to the nearest address or named place.

Zoom-level control for address detail: 18=building, 16=street, 14=neighbourhood, 12=town, 10=city, 8=county, 5=state, 3=country
Layer filtering for matched OSM object type
Optional extra OSM tags (contact, metadata, and physical attributes) and language preference
Returns structured address breakdown, OSM type/ID, and bounding box
Matches on proximity and layer, never on an OSM attribute tag — extratags decorates the matched object and cannot select one. To find the objects in an area carrying a given tag, use openstreetmap_query_nearby, openstreetmap_query_bbox, or openstreetmap_query_raw

`openstreetmap_lookup_objects`

Fetch full Nominatim address records for known OSM object IDs.

Accepts an array of up to 50 IDs; a single ID is passed wrapped, e.g. ["N240109189"]
IDs must be prefixed with N (node), W (way), or R (relation): e.g., "N240109189", "W50637691", "R146656"
Efficient alternative to a full geocoding round-trip when OSM IDs are already known (e.g., from an Overpass result)
Reports not_found list for IDs that returned no result
Optional extra OSM tags (contact, metadata, and physical attributes) and language preference
Returns exactly the objects named in osm_ids — extratags decorates them and cannot select them. Discover objects by tag with openstreetmap_query_nearby, openstreetmap_query_bbox, or openstreetmap_query_raw, then pass their IDs here

`openstreetmap_query_nearby`

Find OSM features within a radius around a point via the Overpass API.

Primary tool for "what's near X?" spatial queries
Supports amenity shortcut for common POI types (hospital, pharmacy, restaurant, cafe, school, atm) or tag_key + tag_value for any OSM category (leisure=park, shop=supermarket, natural=peak)
Configurable radius up to 50km; keep under 5km for dense urban POI queries
Element type filtering: node (standalone POIs), way (buildings/areas), relation (complex structures)
Limit up to 500 results; truncated flag signals when more exist
Returns OSM type/ID, coordinates, name, and full tag set for each feature

`openstreetmap_query_bbox`

Find OSM features within a rectangular geographic bounding box.

Useful for area surveys where proximity to a single point isn't the goal
Same amenity / tag_key + tag_value interface as openstreetmap_query_nearby
A west greater than east is a box crossing the antimeridian, covering west..180 plus -180..east; only south greater than north is rejected
Configurable timeout for large bounding boxes or dense areas
Limit up to 500 results with truncated flag

`openstreetmap_query_raw`

Execute arbitrary Overpass QL for queries the convenience tools don't cover.

Full Overpass QL expressiveness: multi-type queries, union queries, relation membership, historical queries
Query must include [out:json]; server injects [timeout:N] if absent
Returns raw element array — structure varies by query type (nodes have lat/lon, ways have nodes[], relations have members[])
Limit up to 500 elements per call with totalFound / truncated / nextOffset disclosure; page the rest with offset
timeout_seconds up to 180 is honored client-side, so a long-running query is not cut off early
Validate complex queries at overpass-turbo.eu before use

Features

Built on @cyanheads/mcp-ts-core:

Declarative tool definitions — single file per tool, framework handles registration and validation
Unified error handling across all tools
Pluggable auth (none, jwt, oauth)
Swappable storage backends: in-memory, filesystem, Supabase, Cloudflare KV/R2/D1
Structured logging with optional OpenTelemetry tracing
Runs locally (stdio/HTTP) or on Cloudflare Workers from the same codebase

Nominatim/Overpass-specific:

Nominatim usage policy compliance: configurable User-Agent via OSM_USER_AGENT, rate-limit-aware request handling
Overpass slot budget respected client-side: concurrent submissions capped by OSM_OVERPASS_MAX_CONCURRENCY, and a throttled endpoint is never re-submitted to — the call advances to the next endpoint instead, and fails only once every one has refused it
Opt-in Overpass endpoint failover: list mirrors in OSM_OVERPASS_ENDPOINTS and a transient failure advances to the next one inside the same call. Deterministic failures (malformed query, result too large) stay on one endpoint, and every response reports the endpoint that served it
OSM attribution on every response (Data © OpenStreetMap contributors, ODbL 1.0)
Private instance support — override OSM_NOMINATIM_BASE_URL and OSM_OVERPASS_BASE_URL for self-hosted or mirror endpoints
Structured error contracts: no_results, no_coverage, conflicting_query_mode, missing_query_mode, invalid_id_format, invalid_tag, invalid_bbox, query_timeout, rate_limited, upstream_error, query_error, result_too_large, overpass_gateway_timeout, overpass_unavailable, endpoints_exhausted — all with actionable recovery hints
Overpass rejections carry the upstream cause: the whole error document is captured, so an Overpass 5xx surfaces its runtime error: ... remark on every Overpass tool, and a malformed openstreetmap_query_raw query its line N: parse error: ... detail, instead of a bare status

Agent-friendly output:

Attribution on every response — agents can surface the ODbL license notice as required
Structured output contracts — coordinates, OSM IDs, address fields, and tag maps in consistent shapes
Cross-tool chaining: Overpass results carry osm_type + osm_id that feed directly into openstreetmap_lookup_objects for full address records

Getting started

Self-Hosted / Local

Add the following to your MCP client configuration file.

{
  "mcpServers": {
    "openstreetmap-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/openstreetmap-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "openstreetmap-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/openstreetmap-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

Bun v1.3.0 or higher (or Node.js ≥24.0.0).
No API key required — Nominatim and Overpass are public APIs. For heavy use, consider pointing OSM_NOMINATIM_BASE_URL and OSM_OVERPASS_BASE_URL at self-hosted or mirror instances.

Installation

Clone the repository:

git clone https://github.com/cyanheads/openstreetmap-mcp-server.git

Navigate into the directory:

cd openstreetmap-mcp-server

Install dependencies:

bun install

Configuration

All configuration is validated at startup via Zod schemas in src/config/server-config.ts. Key environment variables:

| Variable | Description | Default | |:---|:---|:---| | MCP_TRANSPORT_TYPE | Transport: stdio or http | stdio | | MCP_HTTP_PORT | HTTP server port | 3010 | | MCP_HTTP_ENDPOINT_PATH | HTTP endpoint path where the MCP server is mounted | /mcp | | MCP_PUBLIC_URL | Public origin override for TLS-terminating reverse-proxy deployments | none | | MCP_AUTH_MODE | Authentication: none, jwt, or oauth | none | | MCP_LOG_LEVEL | Log level (debug, info, warning, error, etc.) | info | | MCP_GC_PRESSURE_INTERVAL_MS | Opt-in Bun-only forced-GC pressure loop (ms). Recommended starting point if heap growth is observed: 60000. | 0 (disabled) | | STORAGE_PROVIDER_TYPE | Storage backend: in-memory, filesystem, supabase, cloudflare-kv/r2/d1 | in-memory | | OSM_NOMINATIM_BASE_URL | Nominatim API base URL. Override for a private or mirror instance. A path prefix is supported for instances proxied under a subpath (e.g. https://maps.example.com/nominatim), with or without a trailing slash. | https://nominatim.openstreetmap.org | | OSM_OVERPASS_BASE_URL | Overpass API endpoint URL. When set, pins every query to this one endpoint and disables mirror failover — what a private-instance deployment wants. Leave unset to use OSM_OVERPASS_ENDPOINTS. | unset | | OSM_OVERPASS_ENDPOINTS | Comma-separated ordered list of Overpass endpoints. On a transient failure (5xx, HTML throttle page, connection timeout) the same tool call advances to the next entry, so a degraded endpoint costs latency instead of the answer; the first entry stays the preferred one. A single entry means no failover. Ignored when OSM_OVERPASS_BASE_URL is set. See Overpass endpoint failover. | https://overpass-api.de/api/interpreter | | OSM_OVERPASS_MAX_CONCURRENCY | Maximum Overpass queries submitted at once; queries past the cap queue locally. Match the slot budget the endpoint advertises at /api/status. The endpoint keeps a slot reserved for the full [timeout:N] after answering, so a burst can still draw an HTTP 429 — that endpoint is then skipped for the rest of the call rather than re-submitted to, and rate_limited surfaces once every configured endpoint has refused. | 2 | | OSM_USER_AGENT | User-Agent sent to Nominatim and Overpass. Required by usage policy. | openstreetmap-mcp-server/<package version> | | OTEL_ENABLED | Enable OpenTelemetry | false |

Overpass endpoint failover

Out of the box the server queries one Overpass endpoint, the FOSSGIS-operated main instance. A degraded endpoint therefore fails the call — openstreetmap_query_nearby, openstreetmap_query_bbox, and openstreetmap_query_raw all depend on it.

Listing more than one endpoint in OSM_OVERPASS_ENDPOINTS turns on failover: a transient failure advances to the next entry inside the same tool call, and the list is tried in order so the first entry stays preferred. Throttling counts — an endpoint that answers HTTP 429 or a throttle page is skipped for the rest of the call rather than re-asked, so the query reaches a mirror with a free slot.

OSM_OVERPASS_ENDPOINTS="https://overpass-api.de/api/interpreter,https://overpass.private.coffee/api/interpreter"

Failover is opt-in rather than the default because adding an endpoint sends your queries to a third party, on their terms and their bandwidth. Before listing one:

Confirm the operator welcomes general client use. The OSM wiki instance list records each instance's stated usage policy, and they differ sharply — some grant open use, others require an API key or payment, others ask you to contact the operator first. overpass.private.coffee, for one, publishes a grant covering any project including commercial use, alongside prohibited-use terms and a request to be told in advance about large-scale use.
Check the data coverage. Region-scoped instances answer a query outside their extract with HTTP 200 and an empty element list — a silent wrong answer rather than an error — so they are unfit as a general-purpose fallback no matter how healthy they are. The wiki list separates global instances from regional ones.
Check the freshness. Mirrors can lag the main instance, sometimes by weeks. Every response reports which endpoint served it in the servingEndpoint enrichment field alongside the data_timestamp output field, so a stale or unexpected result stays attributable.

OSM_USER_AGENT is sent to every endpoint, and its default identifies this server and its version, which is what the main instance's policy asks for. An endpoint you add is governed by its own policy as well.

Two other behaviors bound what a failover can cost. OSM_OVERPASS_MAX_CONCURRENCY is one budget across all endpoints, so rotating never raises the number of submissions in flight. And one tool call stops submitting once it has spent its time budget — per-attempt deadline, queue wait, and retry backoff all count against that — surfacing endpoints_exhausted rather than multiplying a per-attempt deadline by the retry budget. The budget is at least 120 seconds and widens with the [timeout:N] a query carries, so a long openstreetmap_query_raw timeout is honored without lengthening every other call.

Setting OSM_OVERPASS_BASE_URL pins that single endpoint and disables failover, unchanged from previous releases: a private or self-hosted instance is not interchangeable with a public mirror.

Running the server

Local development

Build and run the production version:

# One-time build
bun run rebuild

# Run the built server
bun run start:http
# or
bun run start:stdio

Run checks and tests:

bun run devcheck  # Lints, formats, type-checks, and more
bun run test      # Runs the test suite

Project structure

| Directory | Purpose | |:---|:---| | src/mcp-server/tools | Tool definitions (*.tool.ts). Six tools across Nominatim and Overpass. | | src/services/nominatim | Nominatim service layer — API client, search, reverse, lookup. | | src/services/overpass | Overpass service layer — query builder, executor, element normalizer. | | src/config | Server-specific environment variable parsing and validation with Zod. |

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

Handlers throw, framework catches — no try/catch in tool logic
Use ctx.log for logging, ctx.state for storage
Register new tools and resources in the createApp() arrays

Contributing

Issues and pull requests are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

This project is licensed under the Apache 2.0 License. See the LICENSE file for details.

Map data from OpenStreetMap contributors, available under the Open Database License (ODbL).

Published

Vulnerabilities

Links

Maintainers

Keywords

Readme