marktplaats-mcp

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List categories

list_categories

Read-onlyIdempotent

Retrieve category and subcategory names and IDs from the shared Marktplaats and 2dehands category tree to build accurate listing search filters.

Instructions

Browse the category tree (shared by marktplaats.nl and 2dehands.be) to find names/ids for search_listings' category and subcategory filters.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_categories"
  }
}

Input Schema

Name	Required	Description	Default
`parent`	No	Omit for all top-level categories; pass a top-level category name or id for its subcategories.

Output Schema

Name	Required	Description	Default
`level`	Yes
`parent`	No
`categories`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv0.2.0Sep 26, 2026

removedOutput schema / additionalProperties
```
Removed value: -true
```

addedOutput schema / properties

Added value: +{
+  "categories": {
+    "items": {
+      "properties": {
+        "id": {
+          "title": "Id",
+          "type": "integer"
+        },
+        "name": {
+          "title": "Name",
+          "type": "string"
+        },
+        "parent": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Parent"
+        }
+      },
+      "required": [
+        "id",
+        "name"
+      ],
+      "title": "Category",
+      "type": "object"
+    },
+    "title": "Categories",
+    "type": "array"
+  },
+  "level": {
+    "enum": [
+      "L1",
+      "L2"
+    ],
+    "title": "Level",
+    "type": "string"
+  },
+  "parent": {
+    "anyOf": [
+      {
+        "type": "string"
+      },
+      {
+        "type": "null"
+      }
+    ],
+    "default": null,
+    "title": "Parent"
+  }
+}

addedOutput schema / required

Added value: +[
+  "level",
+  "categories"
+]

addedOutput schema / title
```
Added value: +"CategoriesResult"
```

First observedv0.1.1Jul 15, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description's 'Browse' aligns perfectly. The description adds context that the tree is shared between marktplaats.nl and 2dehands.be, which is useful beyond annotations. No contradiction.

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?

One sentence, front-loaded with the core purpose, no filler. The description is precisely as long as needed.

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?

For a simple read-only tool with one optional parameter, an output schema, and annotations covering safety, the description is complete. It tells the agent what the tool does and why it's useful, leaving no essential gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema fully documents the single `parent` parameter, including its nullability and semantics. The description adds no additional parameter detail beyond the schema, so with 100% schema coverage, a baseline of 3 is appropriate.

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 it browses a category tree shared across two marketplaces, with the explicit purpose of finding names/ids for search_listings filters. This distinguishes it from sibling tools by tying it to a specific downstream use.

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 explains when to use this tool: to obtain category names/ids for search_listings filters. It implies that it's the go-to for exploring the category hierarchy, though it doesn't explicitly mention alternatives or when not to use it. Still, the purpose is actionable.

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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