list_libraries

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

With no annotations, the description carries the full burden. It accurately conveys a read-only listing operation and mentions the output cardinality (count of entries per library). It does not disclose any side effects, but 'list' implies no mutation. It could explicitly say it is non-destructive, but the nature of a list operation makes that self-evident, and no permissions or rate limits are relevant for a simple read. The transparency is adequate.

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?

A single, front-loaded sentence that states exactly what the tool does and what it returns. No filler or repetition—every word earns its place.

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?

The tool is simple: no parameters, a clear purpose, and an output schema (provided as structured data). The description fully covers the operation and necessary context. There is nothing an agent needs to know that isn't already explained.

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 is empty. Per rubric, 0 params gives a baseline of 4. The description adds no parameter details because none exist; it is fully consistent with the schema.

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 action ('List') and a precise resource ('configured JabRef libraries') plus the output detail (number of parsed entries). It clearly distinguishes itself from siblings like list_entries (lists entries), get_entry (fetches one), search (queries), get_pdf (retrieves files), and add_entry (mutates). No ambiguity.

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 explains what the tool does but does not explicitly state when to use it over alternatives or when not to use it. Although the sibling tool names make the differentiation obvious, there is no direct guidance such as 'Use this to see all libraries; for entries within a library use list_entries.' A clear context but no exclusions or explicit routing.

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