Summarise a document selection

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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior, so the safety profile is covered. The description adds useful semantics about aggregated counting and the one-call efficiency, but does not discuss edge behavior such as missing IDs, duplicate IDs, or how the open-world hint affects result completeness.

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 concise sentences fully convey the operation and use case with no redundant wording. The core behavior is front-loaded and the explanatory analogy is efficient.

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?

Despite lacking an output schema, the description adequately conveys what the result represents: counts of documents per tag, correspondent, type, and storage path. Given the single-parameter surface and rich annotations, this is nearly complete, though exact response structure is left unspecified.

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 provides only the type and constraints for the single `documents` parameter, with no description. The tool description adds that these are document IDs and that they form a selection, which is meaningful but minimal; it does not explain duplicate handling, limits, or invalid-ID behavior.

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: given a set of document IDs, return counts per tag, correspondent, document type, and storage path. The use-case phrasing "what is in this pile?" makes the tool's role immediately clear and distinguishes it from individual document-fetching tools.

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 clearly indicates when to use this tool: when aggregate summaries of a document selection are needed, and contrasts it with fetching every document. It does not name sibling alternatives explicitly, nor note when to avoid it, so it falls just short of full explicit routing guidance.

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