Carat Hunter

Market price for a diamond spec

price_check

Read-only

Typical listed prices for a spec (carat size, colour, clarity, shape, origin) across all retailers Carat Hunter tracks, with the day they were measured, as its insights page shows them: stones with a recently confirmed price, their median and typical range (10th to 90th percentile), how many retailers list them, and how much the same certified stone typically varies between retailers. Carat sizes: 0.3, 0.5, 0.75, 1, 1.5, 2, 3, 5 (each the start of a range: 1 covers 1.00 to 1.49ct).

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": {
      "carat": "<carat>",
      "colour": "<colour>",
      "clarity": "<clarity>",
      "shape": "<shape>",
      "origin": "<origin>"
    },
    "name": "price_check"
  }
}

Input Schema

Name	Required	Description	Default
`carat`	Yes
`shape`	Yes
`colour`	Yes
`origin`	Yes
`clarity`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedSep 25, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare this is a read-only, closed-world lookup, so the safety profile is covered. The description adds genuinely useful behavioral context about what comes back: median, 10th-to-90th percentile range, retailer counts, inter-retailer variation, and the measurement date. It does not mention caching, coverage limits, or what happens when a spec has thin data.

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 purpose and the returned statistics are front-loaded, with the carat-bucket rule isolated at the end where it reads as a note. It is a dense single sentence and could have been split into a purpose line plus an output line, but no sentence is 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?

There is no output schema, so the description must describe return values, and it does so concretely (median, percentile range, retailer count, price spread, measurement date). For a five-parameter, five-enum read-only lookup this is close to sufficient; only thin-data behavior and coverage caveats are missing.

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?

With 0% schema description coverage, the description carries the full burden, and it does the most important part: explaining that carat enums are bucket starts (1 covers 1.00–1.49ct), which is non-obvious from a bare enum of 0.3/0.5/1/1.5. It also names all five spec dimensions. It leaves colour and clarity grades and the natural vs lab-grown distinction unexplained, though those are standard industry encodings.

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 names the resource precisely: typical listed prices for a diamond spec (carat, colour, clarity, shape, origin) aggregated across tracked retailers. It goes beyond a bare verb by scoping the resource to a spec and enumerating the spec dimensions, which separates it from a broad market tool. It never names a sibling such as market_overview or search_diamonds, so differentiation must be inferred.

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?

There is no statement of when to call this versus market_overview or search_diamonds, and no prerequisites or exclusions. An agent can infer that a full spec is required because all five parameters are mandatory, but the description itself offers no routing guidance.

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

All Carat Hunter tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?