Mercado Libre MCP Server

update_stock

Update the available quantity of a Mercado Libre listing by item ID and new stock count, returning the previous and new stock levels for inventory tracking.

Instructions

Actualiza el stock/cantidad disponible de una publicación en Mercado Libre. Retorna stock anterior y nuevo.

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": {
      "item_id": "<item_id>",
      "quantity": "<quantity>"
    },
    "name": "update_stock"
  }
}

Input Schema

Name	Required	Description	Default
`item_id`	Yes	ID de la publicación (ej: MLA1234567890)
`quantity`	Yes	Nueva cantidad disponible

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.2.0-alpha.3Nov 8, 2026

TDQS

A3.6/5.0

Behavior3/5

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

With no annotations, the description carries the full burden. It does disclose the return values (old and new stock) and, via the schema wording 'Nueva cantidad disponible', implies an absolute overwrite rather than a relative adjustment. However, it says nothing about permissions, whether the change is reversible, error conditions, or rate limits for a mutation tool.

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?

Two short sentences, front-loaded with the action and resource, followed by the return behavior. Nothing is wasted and there is no filler.

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?

For a simple two-parameter mutation with fully documented schema, the description covers the action and the return shape. The main remaining gap is that, with no annotations, the overwrite/mutation semantics and any preconditions are only implicit.

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?

Schema description coverage is 100% — item_id and quantity are both documented in the schema with an example ID format and a minimum of 0. The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource: updates the available stock/quantity of a Mercado Libre listing, and even notes the return payload (previous and new stock). It is clearly distinguishable from siblings such as update_price, though it does not explicitly name any alternative.

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

Usage Guidelines3/5

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

Usage is implied by the resource: call it when you need to change a listing's available quantity. There is no explicit when-to-use vs when-not guidance, no mention of prerequisites (e.g., item must be active, auth requirements), and no reference to sibling tools like stockout_risk that might precede it.

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

Deploy Server