get_index_stats

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

With no annotations, the description carries the full burden and does so well: it states read-only, no side effects, and clarifies that the tool does not load the embedding model or initialize BM25. It also describes the returned metrics, giving the agent a clear behavioral picture.

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 well structured and front-loaded, with purpose, safety, returns, and usage separated clearly. It is slightly verbose in listing return fields even though an output schema exists, but the extra context remains useful rather than wasteful.

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 zero-parameter schema, lack of annotations, and presence of an output schema, the description supplies everything needed: purpose, safety profile, non-effects, usage context, and sibling alternatives. No important agent-facing context is missing.

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 parameter semantics are inherently minimal. A baseline of 4 is appropriate because there are no parameters to misinterpret and the schema is empty.

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 states a specific verb and resource: get statistics and health metrics for the knowledge base index. It clearly distinguishes the tool from siblings by naming list_categories for per-category counts and evaluate_retrieval for search quality measurement.

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?

It explicitly says to use this for system health checks, embedding runtime status, index population, and cache efficiency. It also provides clear alternatives: list_categories for per-category document counts and evaluate_retrieval for actual search quality.

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