list_categories

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

The description states the tool is read-only with no side effects and reflects the live index state. Since no annotations are provided, this fully covers behavioral traits such as safety and data freshness.

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 three short sentences, each adding value: purpose, behavior, and usage guidance. It is efficiently front-loaded with the core 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 the tool is parameterless and has an output schema, the description covers everything needed: what it does, what it returns (category names, counts, total), and when to use it. No gaps.

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 zero parameters and schema description coverage is 100% (trivially). There are no parameters to explain, so the description adds no parameter semantics, but this is acceptable for a parameterless tool. Baseline 4 for 0 params.

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 lists all document categories with their document counts, using a specific verb ('List') and resource ('document categories'). It is distinct from siblings like 'list_documents' which lists documents, not categories.

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 explicitly advises using this tool before filtering search_knowledge or list_documents by category, and suggests get_index_stats as an alternative for broader system health metrics. This provides clear when-to-use and when-not-to-use guidance.

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