get_commoditiesWTI, Brent and natural gas reference prices (weekly). Costs EUR 0.002 per call.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "get_commodities"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnly, idempotent, closed-world, and non-destructive behavior, so the description is free to add value elsewhere. It does so by disclosing the per-call price (EUR 0.002) and the weekly update cadence, both of which materially affect whether and how often an agent should call it. It stops short of describing response shape or how current the weekly prices are.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two compact clauses with zero filler: the data payload comes first and the cost second, which is the right priority order. Every word carries information an agent needs.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a parameterless read tool with full annotation coverage and no output schema, the description covers the essentials: what instruments, what cadence, what cost. Minor gaps remain around the response format and the currency/unit of the quoted prices, but nothing critical to invocation is missing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool takes zero parameters, so there is no parameter meaning for the description to add and the baseline of 4 applies. The empty schema plus the description's explicit instrument list fully frames what a call returns the prices for.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names the exact resource returned (WTI, Brent, and natural gas reference prices) and its granularity (weekly), so an agent can tell it apart from get_fx_rates or get_crypto_tickers without opening a schema. It lacks an explicit verb, but the resource specificity compensates and leaves no ambiguity about what data is served.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage is only implied: an agent infers it should call this when it needs commodity price references. There is no explicit when-to-use framing, no note on what to use instead for currencies, equities, or crypto, and no mention of staleness limits given weekly data.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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