MercadoLibre MCP Server

by dedero1985

Overview Schema Source Related Servers Discussions Admin

Create Item

create_item

Create a new MercadoLibre product listing with title, price, category, and stock, using an authenticated seller account for the selected country.

Instructions

Create a new product listing on MercadoLibre.

Requires OAuth2 write scope on the profile matching site_id — that profile's authenticated account is the one that will own the new listing. Use predict_category/list_categories first to find valid category IDs.

Usage examples:

"Create a listing for an iPhone 15 at 1500 ARS in category MLA1051" → site_id="MLA"
"Publish a new running shoes product in Uruguay for 2500 UYU" → site_id="MLU"

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "input": "<input>"
    },
    "name": "create_item"
  }
}

Input Schema

Name	Required	Description	Default
`input`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.3.2Sep 15, 2026

addedInput schema / properties / input / properties / attributes

Added value: +{
+  "anyOf": [
+    {
+      "items": {
+        "additionalProperties": {
+          "type": "string"
+        },
+        "type": "object"
+      },
+      "type": "array"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Item attributes, e.g. [{\"id\": \"BRAND\", \"value_name\": \"Ubiquiti\"}]"
+}

addedInput schema / properties / input / properties / family_name

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Product family name"
+}

First observedv0.1.0Sep 11, 2026

TDQS

A4.1/5.0

Behavior4/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly states the OAuth2 write scope requirement and that the authenticated account matching site_id will own the listing. It also mentions the need to validate category IDs first. While it doesn't discuss side effects like rate limits or error handling, it covers the most critical behavioral aspects (auth and ownership) for a create operation.

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?

The description is reasonably concise for a complex tool. It front-loads the primary purpose, then provides essential prerequisites and usage examples. The structure is logical: what it does, what's required, and examples. It avoids unnecessary verbosity, though the examples add a bit of length. Overall, it earns its place.

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 tool's complexity (nested input object, many parameters, output schema present), the description covers the critical context: OAuth2 scope, ownership, prerequisite tool usage, and site/account selection. It also provides examples that clarify common usage. While it doesn't address error handling or failure modes, the presence of an output schema mitigates the need to explain return values. The description is sufficient for an agent to use the tool correctly in most scenarios.

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 tool description does not directly explain parameters (schema description coverage is 0%), but the input schema itself provides rich descriptions for each parameter (e.g., price, title, site_id, account). The description adds value by explaining the relationship between site_id and account selection, and it gives usage examples that illustrate how to set these fields. However, it doesn't systematically cover all parameters or add semantics beyond what the schema already provides, so 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 the tool's purpose: 'Create a new product listing on MercadoLibre.' It uses a specific verb and resource, and the distinction from siblings like update_item, delete_item, and relist_item is obvious. The usage examples further clarify what kind of operations fall under this tool, making it unambiguous.

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 provides clear usage context: it requires OAuth2 write scope, instructs to use predict_category/list_categories first to find valid category IDs, and gives examples showing how to specify site_id. While it doesn't explicitly state when NOT to use this tool (e.g., for updates), the context is strong enough that an agent would know when to invoke it. The prerequisite guidance and examples effectively route the agent.

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