What3words

Autosuggest

autosuggest

Read-onlyIdempotent

Given a partial / mistyped 3-word input, return ranked suggestions. Optional focus point biases results toward proximity.

Input Schema

Name	Required	Description
`input`	Yes	Partial three-word string
`country`	No	Restrict to ISO country code(s), comma-separated
`language`	No	2-letter language
`n_results`	No	1-100 (default 3)
`focus_latitude`	No	Bias toward this latitude
`focus_longitude`	No	Bias toward this longitude

Output Schema

Name	Required	Description
`count`	Yes	Number of suggestions returned
`input`	Yes	The partial 3-word input submitted
`suggestions`	Yes	List of ranked suggestions

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 22, 2026

addedInput schema / examples

Added value: +[
+  {
+    "input": "filled.count.so"
+  },
+  {
+    "country": "GB",
+    "focus_latitude": 51.520847,
+    "focus_longitude": -0.195521,
+    "input": "index.home",
+    "n_results": 5
+  }
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "count": {
+      "description": "Number of suggestions returned",
+      "type": "number"
+    },
+    "input": {
+      "description": "The partial 3-word input submitted",
+      "type": "string"
+    },
+    "suggestions": {
+      "description": "List of ranked suggestions",
+      "items": {
+        "properties": {
+          "country": {
+            "description": "Country containing the suggestion",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "distance_to_focus_km": {
+            "description": "Distance in km from focus point if provided",
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "language": {
+            "description": "Language code of the suggestion",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "nearest_place": {
+            "description": "Nearest place to the suggestion",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "rank": {
+            "description": "Ranking of the suggestion",
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "words": {
+            "description": "The suggested 3-word address",
+            "type": [
+              "string",
+              "null"
+            ]
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "input",
+    "count",
+    "suggestions"
+  ],
+  "type": "object"
+}

First observedMay 13, 2026

TDQS

A4.4/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds that the tool returns ranked suggestions and can bias by location. This additional context is valuable but does not contradict annotations.

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

Conciseness5/5

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

The description is extremely concise: two sentences, no unnecessary words. The main action is front-loaded, and every word contributes value. Ideal structure for an AI agent.

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?

Given the presence of an output schema (not shown here), the description does not need to explain return values. It covers the input and optional behavior. It lacks mention of error handling or edge cases, but for a straightforward suggestion tool, this is sufficient.

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 description coverage is 100%, so baseline is 3. The description adds meaning: 'partial / mistyped 3-word input' clarifies the input parameter, and 'optional focus point biases results toward proximity' adds context to focus_latitude/focus_longitude. This exceeds the minimal schema documentation.

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?

The description clearly states the tool's purpose: it returns ranked suggestions for partial or mistyped 3-word input. It also mentions the optional focus point parameter for proximity bias. This distinguishes it from siblings like 'words_to_coords' (exact conversion) and 'coords_to_words'.

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

Usage Guidelines4/5

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

The description implies usage context: use when input is partial or mistyped, optionally with a focus point. It provides clear context but does not explicitly state when not to use this tool or name alternatives. Given sibling tools, the context is sufficient for an agent to infer appropriate use.

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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