Sharpest price search

check_price

Read-only

Is this a good price? Give a product (name, model number or eBay item URL) and a price in USD; get where that price sits against today's US eBay listings for it (cheapest, 25th percentile, median, share of listings cheaper) and its 30-day low, with a verdict: great, good, fair or high. Without a price you get the market numbers and an estimated resale value after eBay fees.

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": {
      "product": "<product>"
    },
    "name": "check_price"
  }
}

Input Schema

Name	Required	Description	Default
`product`	Yes	e.g. 'RTX 4070', 'WD Red Plus 8TB', or an ebay.com/itm/ URL
`price_usd`	No	the price you were offered, item + shipping

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 7, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already declare a safe read-only, non-destructive, closed-world operation, and the description adds real substance on top: US eBay scope, 'today's listings', a 30-day low, the four verdict tiers, and the different output when price is omitted. It does not mention rate limits, listing-count limits, or how ambiguity in product matching is handled, which keeps it short of a 5.

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?

Two sentences, front-loaded with the user-facing question and then the input/output contract. The middle sentence is dense with parenthetical stat lists, but every item listed is a real output the caller needs to know; 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?

With no output schema, the description correctly takes on the burden of describing return values (cheapest, p25, median, share cheaper, 30-day low, verdict) and the alternate return shape when price is absent. For a two-parameter read-only tool this is nearly complete; only edge-case behavior for unresolvable products is unaddressed.

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 coverage is already 100%, so the baseline is 3, but the description adds genuine meaning: price is in USD, and the consequence of omitting price_usd is spelled out (market numbers plus estimated resale after fees), which the schema only marks as optional. The product parameter's accepted forms (name, model number, eBay item URL) largely mirror the schema example rather than extend it.

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 states a specific capability: take a product plus a price and report where that price sits against today's US eBay listings, including percentile stats and a verdict. That is clearly distinct from a plain price lookup, but it never names a sibling (get_price, search_prices, price_moves) to draw the boundary explicitly.

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 opening question ('Is this a good price?') frames the use case clearly, and it explicitly describes the alternative mode when no price is supplied (market numbers plus fee-adjusted resale estimate). It lacks any exclusion or pointer to sibling tools, so an agent must still infer which of get_price/search_prices to prefer.

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

All Sharpest price search tools Inspect

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