Mercari MCP Server

search_listings

Search Mercari listings by keyword, with filters for category, price range, and condition.

Instructions

Search Mercari listings by keyword, category, and price range

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": {
      "keyword": "<keyword>"
    },
    "name": "search_listings"
  }
}

Input Schema

Name	Required	Description
`limit`	No	Max results to return (default 20)
`keyword`	Yes	Search keyword
`category`	No	Category filter (e.g. 'Electronics', 'Clothing')
`condition`	No	Item condition filter
`max_price`	No	Maximum price in USD
`min_price`	No	Minimum price in USD

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 28, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations, the description should disclose behavioral traits. It does not mention that it is a read-only operation, any rate limits, pagination behavior, or that it searches public listings only. The limit parameter is present but no pagination details.

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?

Single sentence, no wasted words. Could be more structured with separate sentences for scope or behavior, but adequate.

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

Completeness2/5

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

Given 6 parameters, no output schema, and no annotations, the description is too sparse. It omits return format, pagination, default behavior, and search scope (public vs private).

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 coverage is 100% (all 6 parameters described in schema). The description paraphrases some parameters (keyword, category, price range) but adds no new semantic value beyond the schema.

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?

The description clearly states it searches listings by keyword, category, and price range. However, it does not distinguish from sibling tools like 'get_my_listings' (which searches user's own listings) or 'get_listing_details'.

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

Usage Guidelines2/5

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

No guidance on when to use this tool vs alternatives (e.g., get_my_listings, get_listing_details). The description only states what it does, not when or when not to use it.

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

Deploy Server