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

Annotations already cover the safe-read profile, and the description adds substantial behavior beyond them: data is omitted unless includeData/path is set, an index that is building fails with INDEX_BUILDING, and it quantifies request cost including the extra guard-index read on first data access per session. That is exactly the operational context an agent cannot get from the annotations.

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?

Purpose is front-loaded and every sentence carries technical weight with no filler. It is dense and unformatted as a single paragraph for 14 parameters, which slightly hurts scannability, but nothing is wasted.

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?

With an output schema present, return values need not be re-explained, and the description fills the tricky gaps: includeData/path interaction, filter operator syntax, order values, and the INDEX_BUILDING failure. Remaining minor gaps (e.g. how readonly/activated filtering interacts, pagination termination) are largely covered by the schema.

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?

Schema coverage is 86%, so the baseline is 3, but the description adds real meaning: string indexes match partially, number indexes take lt:/lte:/gt:/gte:, date indexes take before:/after:, and order accepts specific fields or a sorting index pathName. This operator-per-index-type mapping goes beyond the schema's single example.

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?

Opens with a specific verb+resource+scope: 'A page of a list's items', making clear it is a paginated, list-scoped read. The behavior is distinguishable from siblings like search_items or get_item because it is explicitly bound to a single list and its filtering/sorting indexes.

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 points at get_list for discovering filtering indexes and hints that calling get_list avoids an extra request, which is useful routing context. However, it never states when to use list_items versus search_items or get_item, and gives no explicit exclusions, so usage is only implied.

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