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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds context by enumerating the types of metadata returned (filters, groupings, atoms, metrics, detail fields, citation fields), which goes beyond the annotations and helps the agent understand what to expect.

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 a single, front-loaded sentence that lists the key types of information without any unnecessary words. It is highly concise and well-structured.

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's simplicity (no parameters, no nested objects, output schema present), the description fully covers the tool's purpose and scope. It clearly specifies what is described (valid filters, etc.) and is complete for a describe tool.

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 has zero parameters, so the schema provides full coverage trivially. The description does not need to explain parameters, and the baseline for zero-parameter tools is 4. It appropriately focuses on the tool's output content.

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 'Describe valid filters, groupings, atoms, metrics, detail fields, and citation fields for power.generation.' This specifies a concrete action (describe) and distinct resource (power.generation metadata), differentiating it from query_power_generation_v1 and other describe tools.

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 implies this tool is used to obtain metadata before constructing queries, but it does not explicitly state when to use it vs. alternatives like query_power_generation_v1 or other describe tools. No exclusions or alternative guidance is provided.

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