SpotWave electricity prices

Hourly electricity prices for a day

get_prices

Read-onlyIdempotent

Gets one day's electricity prices for a market as hourly averages (normally 24 rows; 23 or 25 on daylight-saving change days), with the day's min, max and average and the cheapest/most expensive hour. Days are day-ahead delivery days in Central European time (Europe/Amsterdam, CET/CEST); hour starts are given in that local time. Prices are per kWh in the market's own currency. Tomorrow's prices are published around 13:00 CET each day; before that, asking for "tomorrow" returns a not-yet-published message. All-in = variable household price per kWh: spot + energy tax + per-kWh grid fee + VAT. Fixed monthly charges (grid capacity, tax credits) are excluded. Spot = wholesale day-ahead price.

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": {
      "market": "<market>",
      "day": "<day>"
    },
    "name": "get_prices"
  }
}

Input Schema

Name	Required	Description	Default
`day`	Yes	"today", "tomorrow", or a date as YYYY-MM-DD (any day from 2021-01-01 up to tomorrow).
`market`	Yes	Market code from list_markets, e.g. "NL", "DE" or "SE3".

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 21, 2026

TDQS

A4.1/5.0

Behavior5/5

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

Annotations already declare readOnly/idempotent/closed-world, yet the description adds substantial unprompted context: 23 or 25 rows on DST change days, day-ahead delivery days in Europe/Amsterdam local time, per-kWh pricing in the market's own currency, and the publication-window failure mode. That is real behavioral disclosure beyond the structured fields.

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?

Front-loaded with the core purpose and row-count semantics before the caveats, and every sentence is informational. The trailing 'All-in = ...' and 'Spot = ...' glossary sentences sit apart from the invocation guidance and lengthen the block, though they do explain response fields.

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

Completeness5/5

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 carries the return-value burden and does so thoroughly: row counts including DST edge cases, aggregate stats, cheapest/most expensive hour, currency, and timezone of hour starts. For a two-parameter read tool this leaves nothing an agent needs unanswered.

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 100%, so the baseline is 3, but the description adds meaning the schema does not: 'tomorrow' is a time-sensitive value with a publication cutoff, dates are day-ahead delivery days in CET/CEST, and prices are in the market's own currency. The market parameter gains the reminder that codes come from list_markets.

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 and resource ('Gets one day's electricity prices for a market as hourly averages') and pins down the output shape (24 rows, min/max/average, cheapest/most expensive hour). It implicitly separates itself from get_current_price and compare_markets via the single-day scope, but never names those siblings explicitly.

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?

Useful operational guidance is present — 'tomorrow' returns a not-yet-published message before ~13:00 CET — but there is no statement of when to pick this over get_current_price or compare_markets. The agent must infer the choice from the tool names alone.

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

All SpotWave electricity prices tools Inspect

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