zcell_list_regions

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's 'Read-only' line adds no new safety information. It does add that the tool 'returns each region and whether it is configured,' which gives some output context beyond the annotations. However, it does not disclose pagination, authentication requirements, or any other behavioral traits.

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 three short sentences with no fluff: it states the action, read-only nature, and output content. The main purpose is front-loaded, and every sentence 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?

This is a simple list tool with good annotations and a well-documented query parameter. However, the 'skip_sku_check' parameter is completely unexplained, and with no output schema the return shape is only partially described. It is adequate for a simple read-only list, but not fully complete.

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 description itself does not explain any parameters. The schema provides a thorough description for the 'query' parameter (JMESPath filtering, snake_case warning, examples), but 'skip_sku_check' has no description in the schema and no mention in the tool description. With schema description coverage at 50%, the tool description fails to compensate for the undocumented parameter.

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 uses a specific verb and resource: 'List the Zscaler Cellular regions available/configured for the customer.' It also clarifies the output ('Returns each region and whether it is configured'), which helps distinguish it from sibling tools like zcell_list_region_operational_status. However, the phrasing 'available/configured' is slightly ambiguous and no explicit sibling differentiation is provided.

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 implies this tool is for retrieving a customer's Zscaler Cellular regions and their configuration state, but it does not state when to use it versus alternatives, nor does it mention any exclusions. The read-only note provides some context, but there is no explicit 'use this over X when...' guidance.

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