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

With no annotations provided, the description carries the transparency burden. It discloses that results may be 'latest available' rather than real-time, and explains optional extras as bundled 'for the same moment.' It implies read-only behavior via the verb 'Get' but does not discuss rate limits or error behavior. Overall, it provides adequate context beyond the schema.

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?

The description is two sentences, front-loaded with the core function. The first sentence states exactly what the tool does, and the second gives usage guidance and optional parameters. No waste, every word contributes.

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 simple read-only price tool, the description is complete enough: it explains purpose, when to use, parameter meanings, and return value hints (price plus optional carbon/renewables). With no output schema, it cannot detail the full response shape, but it gives the essential context for an agent to use it correctly.

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?

Schema description coverage is 100%, so baseline is 3. The description adds semantic value by specifying units for the optional extras (gCO2/kWh, %) and clarifies that they are tied to the same time point as the price. This goes beyond the schema's bare field descriptions.

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 clearly states the tool's purpose: 'Get the latest available electricity spot / current market price for one bidding zone (EUR/MWh).' It uses a specific verb and resource, and the emphasis on 'latest available' and 'current' distinguishes it from siblings like get_day_ahead_prices or get_price_history that cover different timeframes.

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?

The description provides explicit usage context: 'Use when the user asks what power costs right now, or needs a fresh price snapshot.' This clearly indicates when to invoke the tool. However, it does not explicitly mention when not to use it or name alternative tools for other scenarios, so it lacks the full when-not/alternatives detail.

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