get_uk_power_mix

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

With no annotations provided, the description carries the full burden. It clearly states the output (percentage shares of sources) and implied read-only nature. For a simple, no-parameter tool, this is sufficient transparency, though it lacks mention of potential latency or caching.

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 extremely concise: two short sentences that front-load the main purpose and then detail the return value and a usage note. No superfluous information.

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?

Given the tool has no parameters and no output schema, the description fully explains what the tool returns (energy source percentages) and provides a helpful note about no registration. It is complete for its complexity.

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 input schema has no parameters (0 params), so baseline score is 4. The description correctly focuses on the output and does not need to elaborate on parameters.

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?

Description clearly states it returns the current UK power mix with percentage shares for each energy source (Wind, Solar, Nuclear, Gas, Coal). The verb 'get' and resource 'uk power mix' are specific, and the tool is distinct from siblings like 'get_uk_carbon_intensity' and 'get_renewable_percentage_uk' which focus on narrower metrics.

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 indicates it provides the current mix and notes no API registration is needed, which guides usage. However, it does not explicitly mention when not to use this tool versus alternatives, though the simplicity of the tool (no parameters) reduces ambiguity.

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