get_categories

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

With no annotations, the description carries the full burden. It discloses the output content (counts and metric IDs) and the specific categories, but does not explicitly state side effects or safety, though 'List' implies a read-only operation. The added detail about categories and counts provides some transparency beyond a mere 'List categories'.

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 concise sentences: the first states the action and output, the second adds value by listing categories and use case. No redundant filler, and the structure front-loads the functional purpose.

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 zero parameters and no output schema, the description adequately explains the return content (categories, counts, metric IDs) and enumerates the categories. It could specify the exact response structure (e.g., list vs object), but for a simple discovery tool it is largely complete.

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 baseline is 4. The description correctly implies no parameters are needed, and the empty schema confirms this. There is no parameter information to add beyond what the schema already shows.

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 'List all metric categories with counts and metric IDs in each', using a specific verb and resource. It distinguishes itself from siblings like list_metrics by focusing on categories rather than individual metrics, and enumerates the exact categories covered.

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 phrase 'Useful for discovering what data is available' gives clear context on when to use this tool. It does not explicitly name alternatives or exclusions, but the intention is evident, meeting the bar for clear context without explicit exclusions.

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