openstreetmap-mcp-server

Reverse geocode coordinates to an address

openstreetmap_reverse_geocode

Read-onlyIdempotent

Convert latitude/longitude coordinates to the nearest address or place name via Nominatim/OpenStreetMap. Returns the closest matching OSM object at the given coordinates. Note: Nominatim finds the nearest indexed OSM object — in dense areas this may differ from the address at the exact coordinate. Use zoom=18 for building-level accuracy, lower zoom values for coarser resolution (e.g., zoom=10 for city-level). The match is made 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 that carry a given tag, use openstreetmap_query_nearby, openstreetmap_query_bbox, or openstreetmap_query_raw.

Input Schema

TableJSON Schema

Name	Required	Description
`lat`	Yes	Latitude in WGS84 decimal degrees.
`lon`	Yes	Longitude in WGS84 decimal degrees.
`zoom`	No	Address detail level, roughly corresponding to map zoom. 18=building, 16=street, 14=neighbourhood, 12=town, 10=city, 8=county, 5=state, 3=country.
`layer`	No	Restrict which OSM layer is matched. Comma-separated: address, poi, railway, natural, manmade. Default: address,poi.
`language`	No	Preferred language for the result (BCP 47 code or Accept-Language string).
`extratags`	No	Include the extra OSM tags the matched object carries — contact and metadata tags (phone, website, opening_hours, wikidata) and physical attribute tags alike (surface, tracktype, sac_scale, ele, access). Opportunistic, not selective: it reports whatever the matched object happens to carry, so an absent tag describes that object rather than OpenStreetMap, and no value here can steer which object is matched.

Output Schema

TableJSON Schema

Name	Required	Description
`error`	No	Present when the call failed. Absent on success.
`result`	No	The closest matching OSM object at the given coordinates.
`attribution`	No	Required data attribution.
`tagSelectionCaveat`	No	Standing caveat: tag-based selection lives on the Overpass tools (openstreetmap_query_nearby, openstreetmap_query_bbox, openstreetmap_query_raw), never here. extratags decorates the returned objects rather than selecting them, so a missing tag is not evidence the tag is missing from OpenStreetMap. Present when extratags was requested.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

Changed3 schema fields changedSep 3, 2026
- addedOutput schema / properties / result / properties / boundingbox / items
```
Added value: +false
```
- addedOutput schema / properties / result / properties / boundingbox / maxItems
```
Added value: +4
```
- addedOutput schema / properties / result / properties / boundingbox / minItems
```
Added value: +4
```

Changed8 schema fields changedAug 25, 2026

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

addedInput schema / additionalProperties
```
Added value: +false
```

changedOutput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

addedOutput schema / anyOf

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "result",
+      "attribution"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

addedOutput schema / properties / error

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `no_coverage`: Nominatim returns an error indicating no OSM data at the given coordinates (e.g., open ocean or unmapped territory). `rate_limited`: Nominatim returned HTTP 429, or answered HTTP 200 with a throttle document instead of JSON — the one request per second usage policy was exceeded. `upstream_error`: Nominatim returned an unexpected non-2xx status other than 429, or answered HTTP 200 with a body that is not JSON and carries no throttle signature. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "no_coverage",
+            "rate_limited",
+            "upstream_error"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

removedOutput schema / properties / result / properties / boundingbox / items

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "string"
-  },
-  {
-    "type": "string"
-  },
-  {
-    "type": "string"
-  }
-]

addedOutput schema / properties / result / properties / boundingbox / prefixItems

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "string"
+  },
+  {
+    "type": "string"
+  },
+  {
+    "type": "string"
+  }
+]

removedOutput schema / required

Removed value: -[
-  "result",
-  "attribution"
-]

Changed3 schema fields changedAug 10, 2026

changedInput schema / properties / extratags / description

Previous value: -"Include extra OSM tags when available (phone, website, opening_hours, wikidata, etc.)."New value: +"Include the extra OSM tags the matched object carries — contact and metadata tags (phone, website, opening_hours, wikidata) and physical attribute tags alike (surface, tracktype, sac_scale, ele, access). Opportunistic, not selective: it reports whatever the matched object happens to carry, so an absent tag describes that object rather than OpenStreetMap, and no value here can steer which object is matched."

changedOutput schema / properties / result / properties / extratags / description

Previous value: -"Additional OSM tags (phone, website, opening_hours, wikidata). Present only when extratags was requested."New value: +"Extra OSM tags this object carries — contact and metadata (phone, website, opening_hours, wikidata) and physical attributes (surface, tracktype, sac_scale, ele, access). Present only when extratags was requested; an absent tag describes this object, not OpenStreetMap."

addedOutput schema / properties / tagSelectionCaveat

Added value: +{
+  "description": "Standing caveat: tag-based selection lives on the Overpass tools (openstreetmap_query_nearby, openstreetmap_query_bbox, openstreetmap_query_raw), never here. extratags decorates the returned objects rather than selecting them, so a missing tag is not evidence the tag is missing from OpenStreetMap. Present when extratags was requested.",
+  "type": "string"
+}

AddedJul 26, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations already declare readOnly, openWorld, and idempotent, but the description adds essential behavioral caveats beyond them: nearest indexed OSM object may differ from the exact coordinate in dense areas, extratags is opportunistic and cannot select the matched object, and matching is by proximity/layer only. No contradiction with annotations.

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?

Dense and front-loaded: the core purpose is in the first sentence, caveats follow logically, and the sibling routing is kept at the end. Slightly long, but every sentence earns its place given Nominatim's subtle behavior and the 6-parameter surface.

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

Completeness5/5

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

Complete for a reverse-geocoding tool with an output schema. It covers coordinate conversion behavior, zoom semantics, layer matching, extratags limitations, and alternative tools. Nothing an agent needs to call it correctly appears to be missing.

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, but the description adds meaningful context beyond the schema: zoom=18 for building-level accuracy, lower zoom for coarser resolution, and the important clarification that extratags decorates the matched object and cannot be used to influence which object is matched.

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 ('Convert'), resource ('latitude/longitude coordinates'), and outcome ('nearest address or place name via Nominatim/OpenStreetMap'). Distinctly differentiates from tag-query siblings by naming them explicitly and clarifying that this tool matches on proximity/layer, not on OSM attribute tags.

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?

Gives explicit when-to-use and when-not-to-use guidance: use this for reverse geocoding coordinates, and for finding objects carrying a given tag it directs the agent to openstreetmap_query_nearby, openstreetmap_query_bbox, or openstreetmap_query_raw. Also explains zoom-level tradeoffs for choosing resolution.

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

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TDQS

A4.9/5.0

Disambiguation5/5

Each tool has a clearly distinct purpose: forward geocoding, reverse geocoding, ID-based lookup, bbox queries, nearby radius queries, and raw Overpass queries. Even the two spatial query tools are explicitly differentiated by geometry type.

Naming Consistency5/5

All tools follow the openstreetmap_ verb-based snake_case pattern, with action words like lookup, query, search, and reverse. The three query variants are consistently named with clear qualifiers (bbox, nearby, raw).

Tool Count5/5

Six tools is a well-scoped set for an OpenStreetMap read-only server. Each tool covers a distinct core need without redundancy or padding.

Completeness5/5

The surface covers the major OSM read workflows: geocoding both directions, resolving known IDs, spatial filtering by area or proximity, and a raw escape hatch for advanced queries. No critical lifecycle or query operation is missing for the stated domain.

Reverse geocode coordinates to an address

Input Schema

Output Schema

Schema Changelog

TDQS

Glama MCP Gateway

TDQS

Resources