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

With no annotations provided, the description carries the behavioral disclosure burden. It discloses that the tool returns a complete inventory grouped by category and project with document and passage counts, and its list-oriented nature with no parameters implies a safe, read-only operation.

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?

Two sentences with zero filler. The core output scope and grouping are front-loaded first, and the usage guidance is placed second, making the description efficient and easy to parse.

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?

For a zero-parameter tool, the description covers what is returned, how it is organized, and when to use it. An output schema exists, so the description correctly does not repeat return-field details.

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, and the baseline for parameter semantics is 4. The description adds no parameter details because none are needed; there is nothing for an agent to configure or misinterpret.

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 clear verb and resource: 'Inventory of everything indexed, grouped by category and project, with document and passage counts.' This distinguishes it from siblings like search_docs and get_document by framing it as a discovery tool to use before searching.

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?

Explicitly says 'Use it to discover which ByJG libraries have documentation before searching,' clearly indicating when to invoke it. It implies searching is the alternative but does not explicitly name the sibling tools; however, sibling names are available in context, making the guidance effective.

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